Routine immunization in older adults beyond COVID-19: a qualitative analysis of experiences, perceived barriers and facilitators, and recommendations for improvement

Abstract

Background

Vaccination remains one of the most cost-effective public health strategies. However, declining immunization rates among older adults pose a growing concern. This qualitative study aimed to unveil the experiences, emotional responses, barriers and facilitators, and recommendations for improvement of the National Immunization Program among older Chileans and international migrants residing in three major urban centers in Chile during and after the COVID-19 pandemic.

Methods

A qualitative multiple case study design was employed. Using snowball sampling, a purposive sample of 30 participants aged 65+ (15 Chileans and 15 international migrants) were recruited. Semi-structured interviews were conducted online between 01 January 2023 and 30 April 2024 following a pre-defined guide, and lasting 60–90 min. Interviews were audio-recorded, transcribed verbatim, and analyzed thematically. Ethical approval was obtained before the study was conducted.

Results

Most participants viewed Chile’s vaccination program for older adults as effective. The influenza and COVID-19 vaccines were the most commonly recognized, while awareness of the pneumococcal vaccine was lower among participants. Experiences and emotional responses were varied. Limited vaccine knowledge was observed among those vaccinated in long-term care facilities or whose vaccinations were managed by family members. Six key barriers were identified: (1) insufficient dissemination of information (2), fear of adverse effects (3), perceived incompatibility with chronic conditions (4), mobility and health-related limitations (5), socioeconomic vulnerability, and (6) migration-specific challenges. Also, four facilitators were noted: (1) proximity of vaccination centers (2), respectful treatment by healthcare personnel (3), strong public campaigns, and (4) improved outreach to migrant communities. Multiple recommendations for improvement of the National Immunization Program emerged.

Conclusion

This study revealed that while the national vaccination program is viewed positively, its full potential may be limited by access and information barriers as described by study participants. Participants’ recommendations underscore the need to enhance access to accurate, timely vaccine information, strengthen culturally sensitive service delivery, and promote tailored training for healthcare providers on older people rights and needs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-026-07364-3.

Background

Vaccination is considered among the most efficient and cost-effective strategies in public health. It significantly contributes to the reduction of disease-related mortality and morbidity across all stages of life, as well as to the containment of infectious disease outbreaks [1]. Despite the expansion of universal vaccination coverage in many countries, persistent disparities in vaccination coverage highlight the critical need to examine the modifiable determinants and underlying mechanisms that contribute to vaccine inequities [2, 3]. Globally, estimates suggest that immunization efforts between 2010 and 2015 prevented more than five million deaths annually [4]. Although global coverage for several vaccines nearly doubled between 1980 and 2023, these gains plateaued during the 2010s and were sharply reversed by the COVID-19 pandemic, leaving current coverage levels still below those observed prior to 2020 [5].

In Chile, the National Immunization Program (“Programa Nacional de Inmunizaciones”, PNI thereafter), was established in 1978 and has been an essential component of the country’s public health strategy, offering universal and free access to vaccines for all residents, regardless of any health insurance, migration background, or socioeconomic status [6]. The Ministry of Health promotes a vaccination scheme for older adults that includes annual influenza immunization, free COVID-19 vaccination and boosters, and access to additional respiratory vaccines such as those against respiratory syncytial virus (RSV), all prioritized for individuals aged 60 years and older as part of the national immunization campaigns [7]. The pandemic reinforced the relevance of vaccination in the general population and especially among older people, which were compliant with the COVID-19 vaccine [8]. However, post-pandemic evidence from Chile reveals heterogeneous vaccination status, with declining uptake of the most recent booster doses and geographical disparities in coverage [9].

Chile is a high-income country with mixed public and private health systems located in the Western side of South America facing great socioeconomic and health inequalities [10–12]. Notably, one of the PNI’s key strengths lies in its high national coverage rates, supported by a robust logistical infrastructure and integration [13]. The program is also characterized by strong institutional support and an immunization schedule [6]. Despite these strengths, the PNI faces several challenges like persistent inequities in access among some subgroups, including some older people with limited mobility and access to health care, information about the PNI and with low digital literacy in health [14–16].

Chile was among the first countries in Latin America to prioritize older populations in its national COVID-19 vaccination strategy, achieving coverage rates exceeding 90% for primary series and booster doses among adults aged 60 and above [17]. However, coverage for other vaccines recommended for older adults, such as influenza and pneumococcal vaccines, remains inconsistent. Annual influenza campaigns have reached substantial portions of the older population, yet disparities persist due to regional differences, access barriers, and vaccine hesitancy [17]. Moreover, according to recent estimates, Chile maintains relatively high national immunization coverage across several antigens, but subnational data reveal gaps in reaching vulnerable older adults, particularly in rural and socioeconomically disadvantaged areas [13]. The global Immunization Agenda 2030, an international strategy aimed at strengthening immunization across the life course through equitable access, resilient vaccine systems, and integrated primary health care, highlights the importance of life-course vaccination, and Chile’s experience illustrates both the achievements and the persistent challenges in operationalizing these principles [18, 19].

Beyond structural issues such as public policy limitations, coordination challenges, prioritization of target populations, and the operational capacity of healthcare systems [20], additional barriers have emerged; most notably, a lack of trust in vaccines among some groups [21]. Vaccine hesitancy is influenced by a complex interplay of factors, including the spread of misinformation, concerns about potential side effects, and ideological resistance to immunization [21, 22]. These issues tend to be more pronounced in communities experiencing social exclusion, economic instability, or discrimination [22]. On the other hand, increased vaccine uptake requires a comprehensive approach that relies on fundamental system strengthening, including robust disease surveillance and data collection systems, advancements in vaccine development, effective communication campaigns, and sustained political and socioeconomic support, among other evidence-informed public health strategies [23, 24]. Achieving equitable immunization outcomes requires sustained attention to health equity, strong governmental commitment, affordable vaccine pricing, reliable supply chains, and targeted outreach to underserved populations [25, 26]. In this context, while most immunization efforts prioritize children, vaccination among older people merits special attention.

Vaccination coverage among older adults remains a critical component of global public health, given their high burden of comorbidity, significant disease-related mortality, and substantial impact on healthcare costs and resource utilization [27]. Globally, coverage for vaccines recommended in older age -such as influenza, pneumococcal, and COVID-19- varies significantly across regions and income levels [13]. High-income countries generally report higher uptake, while low- and middle-income countries face persistent challenges related to access, infrastructure, and public trust [17]. In Latin America, the COVID-19 pandemic prompted increased attention to immunization among older populations, leading to improvements in coverage in several countries. However, inequalities remain, particularly in rural areas, and in vulnerable groups like migrants and ethnic minorities [28]. According to WHO/UNICEF estimates, while some Latin American countries have achieved relatively high COVID-19 vaccine coverage among older adults, routine immunization for other age-related diseases such as influenza and pneumococcal disease remains inconsistent [17]. Strengthening immunization systems to include older adults is essential for achieving the goals of the Immunization Agenda 2030, which emphasizes equitable access to vaccines across the life course [18]. Evidence also highlights the importance of integrating older adult vaccination into broader health system strengthening efforts, including surveillance, financing, and community engagement [29].

In Chile, the proportion of individuals aged 65 and older reached 15.2% in 2023 and is projected to increase significantly by 2050, reflecting a rapid demographic shift toward ageing [12]. The proportion of adults aged 60 years and older increased from 9.5% in 1992 to 18.1% in 2022, a trend driven by sustained declines in fertility and mortality alongside rising life expectancy [30]. Additionally, Chile has seen a steady rise in the number of older migrants, with adults aged 60 years and over now representing 6,2% of the migrant population in 2023 -an increasingly significant share that reflects the gradual aging of both migrant and native populations over recent decades [31]. The total migrant population in Chile represents around 10% of the population residing in the country, far above the global average estimates [32–34]. While they initially exhibit better health outcomes than locals both globally and in Chile known as the “healthy migrant effect”- this advantage diminishes over time due to social determinants such as unemployment, lack of health insurance, and limited access to culturally appropriate care [35–37]. Subsequently, investigating the perceptions, experiences, barriers, and recommendations for improvement of vaccination programs among older adult locals and migrants represent a critical gap in the public health and health services arena, particularly in Latin American countries such as Chile.

Beyond existing local evidence of lower vaccination coverage among older people in Chile, these figures lack the crucial context provided by an in-depth study of this population´s perceptions and experiences. This knowledge gap -which encompasses barriers and facilitators to accessing vaccination among locals and international migrants- is potentially shared with other emerging high-income countries in Latin America (LATAM) and globally. Our novel qualitative evidence is poised to inform national research and practice in national policy in Chile, thereby providing a foundational analysis for comparable challenges faced by health systems throughout LATAM and the international landscape.

Methodology

Purpose

To unveil the general experience, emotional responses, perceived barriers and facilitators, and suggestions for improvement of the routine vaccination provided by the Chile’s PNI among older adults, including the COVID-19 vaccine, among both locals and international migrants.

Design and setting

A multiple case study design was employed to explore the phenomenon under investigation [38], following the Consolidated Criteria for Reporting Qualitative Research (COREQ Checklist) standards [39], available in Supplementary file 1. This qualitative approach involves the detailed examination of several bounded systems -referred to as cases- through data collection. Case study methodology is characterized by the use of diverse data sources to construct rich, contextualized understandings of each case, thereby facilitating deeper insights into complex social phenomena [38]. The study was conducted in three major Chilean cities: Antofagasta, located in the arid northern region and known for its significant migrant population; Santiago, the capital and largest urban center situated in the central zone with a Mediterranean climate; and Osorno, in the southern part of the country, characterized by a marine west coast climate. Supplementary file 2 outlines the contextual features of each site [40]. This analysis forms part of a broader research initiative aimed at examining vaccine hesitancy in relation to various immunization campaigns implemented nationally, including the COVID-19 response and the National Immunization Program.

The study included both Chilean-born and international migrant older adults, reflecting the rapidly expanding migrant population in Chile. Evidence from nationally representative surveys shows that international migrants now comprise a growing proportion of the Chilean population and display sociodemographic and health profiles that differ markedly from those of locals, including older adults. Main countries of origin are Venezuela, Peru, Colombia, Haiti and Ecuador [35]. Moreover, migrants are significantly more likely to lack health insurance than Chileans of comparable age, indicating persistent structural inequities in access to health protection [41]. Given these demographic and systemic differences, the inclusion of both groups was essential for the study.

Sample size and sampling

The sample was constructed using both theoretical and practical considerations, aligned with the priority groups identified by Chile’s National Immunization Program. Similar to previous international qualitative research identified in this topic [42–44], the initial target sample size was set at 30 participants. Recruitment was carried out using a snowball sampling method, leveraging networks of community leaders in each study location. We identified community leaders, i.e., members of borough councils, leaders of migrant organizations (n = 9, 3 per city, 5 locals and 4 migrants who reside in different boroughs in each city and had diverse educational level, 8 out of 9 were women) as sample seeds and from them we continued recruitment through snowballing technique. A total of 43 locals and Spanish-speaking migrants aged 65 and older were invited to participate, with approximately 70% agreeing to take part. Those who declined cited lack of time or interest. Once the target sample size was reached -comprising 15 Chilean and 15 migrant participants- recruitment was concluded.

Measurements and procedures

Semi-structured interviews were conducted online by both male and female researchers using a predefined guide, with fieldwork taking place between 01 January 2023 and 30 April 2024, and with each interview lasting between 60 and 90 min. Table 1 presents the sample characteristics, and the interview guide is provided in Supplementary file 3. Internet connection and basic digital literacy was required to participate in the study. In the case of older people with hearing mild impairment and any other limitation, they were invited to be accompanied by a relative or carer to support them during informed consent and interview. No interviews were repeated. All interviews were recorded and transcribed word-for-word into a Microsoft Word^® (Microsoft Corporation, CA, USA) document by trained assistant researchers, including field notes taken during the interview for later analysis. To ensure quality control, random audits were performed on over a third of the transcriptions by a second research team member. Selected quotes were translated to English for publication purposes and independently double-checked by a team member fluent in academic English.

Table 1.

Characterisation of study participants, older people in Chile, locals and migrants (n = 30)

Older people	N	%
City
Antofagasta	10	33%
Santiago	10	33%
Osorno	10	33%
Sex
Male	9	30%
Female	21	70%
Age
65–74	23	77%
75–84	5	17%
85–94	2	7%
Nationality
Chilean	15	50%
Migrant	15	50%
Type of Health Insurance
Public	24	80%
Private	5	17%
Unaffiliated/Doesn´t know	1	3%

Analysis

A codebook thematic analysis was conducted using the predefined categories from the interview guide as an initial coding framework, while simultaneously allowing for inductive identification of new themes that emerged from participants’ accounts. Analysis was conducted manually first by two coders and then confirmed and refined using Atlas.ti. A coding tree was created based on the main dimensions that emerged from the interview guide and followed the structure: (i) General perception (vaccines, vaccination scheme, scheme for older people); (ii) Barriers and facilitators (personal experiences, information received, vaccine administration, barriers, facilitators); (iii) Emotions (primary emotions, apprehensions, fears, coping strategies and resources, sources of information); (iv) Recommendations and suggestions (overall assessment, factors affecting the experience, recommendations); (v) Experience and perceptions among migrants (perception of the vaccination scheme, perception of Chile, barriers -financial, administrative, personal from health teams, facilitators, harmonization of vaccine cards for migrants). This codebook thematic analysis followed a recurrence cases approach [45], which refers to the observation that certain codes, ideas, or patterns recur across multiple interviews, focus groups, or narratives, often forming the basis of thematic analysis.

To strengthen the study’s trustworthiness -credibility and reliability-, several rigor strategies were employed: (i) Triangulation across the two independent coders and participants was used to validate findings and enhance analytical depth [46, 47], as well as additional cross-case comparison between participants to identify patterns of similarities, variation or contradiction [48], and (ii) Reflexive practices were integrated throughout the research process, with the team engaging in ongoing discussions and reflections on preliminary results to enrich thematic development and interpretation. That is, throughout data collection and analysis, we engaged in ongoing reflexivity by explicitly documenting our positionalities as public health researchers with prior engagement in immunization programs, acknowledging how our pro-equity commitments and professional roles (i.e., clinician, qualitative analyst) could shape questioning, rapport, coding, and interpretation; we held team debriefs, and kept an audit trail to enhance transparency, rigor, and trustworthiness [49–52].

Data saturation was assessed retrospectively to explore the need for increasing the sample size, yet it was achieved at 30 interviews for the dimensions of barriers and facilitators to immunization, which was the main focus of the study.

Ethics and funding

This research was independently conducted by the Intercultural Global Health Center (CeSGI) at the Faculties of Medicine and Psychology, Universidad del Desarrollo, with funding from the MSD Grant Global Health Equity Catalyst Fund. Ethical approval was granted by the Scientific Ethics Committee of the Faculty of Medicine, Clínica Alemana, Universidad del Desarrollo.

Results

Characterization of participants

The study included 30 older adults distributed between Chilean nationals (n = 15) and migrants (n = 15), from three regions: Antofagasta (n = 10), Metropolitan Region (n = 10), and Los Lagos (n = 10). The average age was 73 years for national participants and 68 years for migrants. Regarding sex distribution, the national group consisted of 11 women and 4 men, while the migrant group included 10 women and 5 men.

General perceptions about the national immunization plan

Among the interviewed group of older adults, representing diverse regions and nationalities (Table 1), there was a widespread perception of strong adherence to vaccination. Vaccines were generally viewed as beneficial and protective against disease. Many participants justified their trust and compliance with vaccination based on personal life experiences, recalling childhood periods when infectious diseases had severe impacts on the population.

“I think it’s beneficial, that is, in terms of protecting the inhabitants of our country, it’s beneficial as Chileans. I think it helps people, at least, attack the disease or the bug in a more powerful way, but I think it’s always beneficial” (Chilean Woman, 65 years old).

“I come from a family where not getting vaccinated wasn’t an option; it was a must. (…) And later, it was the same with my children; I had all of them vaccinated at every stage. I never, ever questioned it. And I think that shows what civilization is about; we would all be different without vaccines. Because I know, I mean, for example, I had uncles who died of tuberculosis. So I have that background, of people who would die without vaccination. So… that’s how I see vaccines; they protect us, that’s how I understand it.” (Migrant Woman, 69 years old).

“I have a positive view, because I’ve witnessed a lot of illness. When I was a child or even a young person, there was none of what we have now; there were no remedies, not even for tuberculosis or typhus. I lived through several epidemics; scabies, which was terrible. Scabies, measles… I can’t quite remember what the other one was called, the big one… The Spanish flu. Several people in this neighborhood died from it.” (Chilean Man, 94 years old).

However, some participants expressed hesitancy toward vaccines, primarily due to concerns about potential adverse events and reactions. Older study participants emphasized the cumulative effect of receiving multiple vaccines or doses within the same season or even on the same day. Several participants described instances where they were administered two different injections simultaneously -such as pneumococcal, influenza, and/or COVID-19- or were advised to receive multiple COVID-19 doses during a single visit. The overlap of other vaccines with the COVID-19 vaccine generated distrust, largely due to the uncertainties surrounding the latter as a relatively new vaccine. As a result, many study participants reported choosing to receive only some of the recommended doses, often fewer than those advised by public health authorities. Additionally, there was a recurring perception that individuals with underlying health conditions might experience severe adverse events from vaccination. Although this concern was expressed by both Chilean and migrant participants, it was more frequently reported among the latter.

“As I said, there are people who have paid a lot of attention to COVID, but adding pneumonia to the mix is ​​​​a bit too much. It’s actually optional. But personally, I wouldn’t get another vaccine. It’s not that it’s a barrier, it’s just that it’s enough. Because, if you think about it, a vaccine is like the virus that you put in your life system, you know? I have faith that everything is for the good, but it’s too much” (Migrant Man, 65 years old).

Among the interviewed, personal adherence to vaccination was perceived to be high. Additionally, in interviews conducted across all three regions included in the study, participants noted a perceived rise in vaccine rejection among individuals affiliated with evangelical religious groups, as reported by study participants.

“I, as I started saying, believe that vaccines are a protection for health. No, I don’t take the time to question the process, that is, the administration of the vaccine. I say that if there are experts, doctors who have studied and who do this for the benefit of public health, I believe that’s why I go and get vaccinated. No, I don’t question whether it’s something that could harm me.” (Chilean Woman, 69 years old).

“Oh, the evangelicals didn’t get vaccinated, but many of them died. (…) They told me not to get vaccinated, that it was bad. I sometimes used to attend with Christian people, but I don’t go anymore because lately they receive a lot of money. So they would ask for money in an envelope and all that, and they were the ones who didn’t want people to get vaccinated.”(Chilean Woman, 73 years old).

Perceptions of the vaccination plan and schedule in older people

Most study participants considered that Chile has a very effective vaccination program for individuals aged 65 and older. Some participants, however, reported having no opinion on the vaccination plan for older adults, either because they were unfamiliar with it or because they simply received vaccines when instructed to do so, without seeking further information or being able to assess its adequacy. When participants were asked about available older adult vaccines, the influenza vaccine and COVID-19 vaccine were the most frequently mentioned, and to a lesser extent, the pneumococcal vaccine. Study participants attributed the high recognition of the former two to extensive public campaigns and media coverage (particularly on television and radio), a level of dissemination notably absent for the pneumococcal vaccine, which some study participants reported having never heard of.

“I’ve had the influenza…. And Covid too. But the pneumonia you’re telling me about, I didn’t know about that one, I’m missing that one.” (Migrant Woman, 65 years old).

In addition, the influenza vaccine was the most frequently mentioned among the older study participants during the interviews, describing it as a “well-known” vaccine that has been widely promoted through public campaigns. While most participants were familiar with the vaccine and had received it at least once, some expressed a preference not to be vaccinated due to adverse signs, symptoms or events experienced in the past or the belief that the illness it prevents is not particularly severe.

“The influenza vaccine is well-known, in general it’s much better known, it’s been very… it’s been reported everywhere, there’s much more advertising for the flu than for the others. (…) It was on television, there was information everywhere that people had to get vaccinated and that they were available, even privately in pharmacies they would place it (…)” (Chilean Woman, 65 years old).

“My husband insisted: ‘Come on, get the vaccine, get the vaccine! Until I went, got vaccinated, and the girl who gave it to me said: ‘Well, in about a week you might feel like you’ve got the flu.’ And a week later, I caught a cold. And I never used to catch colds! The week after I got the vaccine, I got a cold and I was, I don’t know, sick with a cold the whole winter. ‘Don’t ever take me to your famous flu vaccine again,’ I told him, and I didn’t get vaccinated again. Years went by without me getting vaccinated” (Chilean Woman, 77 years old).

Concerning the COVID-19 vaccination, participants presented highly variable perspectives and often expressed conflicting views, resulting in the broadest spectrum of reactions. On one hand, they noted that the vaccination provided a sense of security by preventing a potentially fatal illness. Conversely, a subgroup that reported receiving the recommended doses partially or fully, cited adverse events like arm pain, abscesses, and fatigue, as well as fear of occurrence of such effects. Several participants described that a pattern of incomplete vaccination was common within their peer groups. Furthermore, concerns regarding the rapid development of the COVID-19 vaccine fuelled uncertainty about potential unknow long-term adverse reactions.

“I’m not afraid of getting vaccinated. What did worry me was the COVID vaccines because I realized they were invented very quickly. So, I think, and I believe it’s not just me. Many people think those vaccines weren’t well tested. So, obviously, under the pressure of what was happening and everything…” (Chilean Man, 70 years old).

The influenza and COVID-19 vaccines were widely recognized among the older adult participants interviewed; however, awareness of the pneumococcal vaccine was markedly lower. While individuals who adhered to the full vaccination schedule were familiar with this vaccine, others -even those who had previously received or were aware of it- could not recall its name or the illness it prevents. Several study participants reported first learning about the pneumococcal vaccine only when attending appointments for influenza or COVID-19 vaccination, indicating a lack of prior information. Additionally, across all older adult profiles, and particularly among migrant participants, study participants stated being unaware of the pneumococcal vaccine; some even reported learning of its existence only during the interview itself. Participants perceived a failure in vaccine dissemination, driven by both poorly targeted public campaigns and insufficient information delivery by healthcare personnel during vaccination visits.

“For example, I think there’s also a lack of information. I had no idea there was the latest one about pneumococcal vaccine. I’m only hearing about it now. Perhaps there’s more information missing about that vaccine. It catches my attention because I get together with a lot of friends, but I don’t remember hearing about it. The only thing I remember hearing about most is the influenza vaccine. But I don’t remember hearing about the pneumococcal vaccine. I didn’t have much information about that one; I didn’t receive any information. It wasn’t that widespread, right? Even if I had known, I would have gotten vaccinated, but I really didn’t know much about it (…)” (Chilean Woman, 65 years old).

“Sometimes you hear that someone had pneumonitis—I mean, I’ve seen people, even a friend who was very ill last year. She had a really hard time, and they asked her if she had gotten the vaccine, but no, she said she hadn’t, never, that she didn’t know about it. So, I think that experience, or bad experiences people have had, lead them to get vaccinated. But I think there are many people who don’t know about it or don’t really believe in that vaccine [pneumococcal]. The influenza vaccine is more ingrained in people’s minds, and maybe the COVID one too, but the pneumonia one doesn’t seem to be very present here.” (Chilean Woman, 66 years old).

Emotional responses, sources of information and support for vaccination adherence

When asked about emotions associated with vaccination, study participants primarily referred to feelings of satisfaction, confidence and protection against dangerous diseases. Nevertheless, alongside these positive emotions, a subgroup of participants expressed fear or apprehension concerning potential adverse events and the frequency and number of administered doses.

“I feel protected, the experiences I’ve had with vaccines have been good. I’ve felt more protected in terms of my health. Like I said, I hardly ever catch a cold, and if I do—like when I went to the south and had a cold—I don’t feel weak, and I feel protected” (Chilean Woman, 70 years old).

A lower level of knowledge about vaccines among study participants vaccinated in long-term care facilities was perceived. The same was identified in cases where a family member was responsible for managing the vaccination schedule. In contrast, most study participants possessed some general vaccination information and tended to adhere to public health recommendations facilitated by public health campaigns and official guidance from the health sector, especially during and following COVID-19.

“I mean, I’m always aware of the vaccination campaigns to stay up to date with my vaccines, because I worry because of my age. There’s influenza, which is super important, and pneumonia, which I knew about from my mom because I’ve taken her to get it, but now I found out it’s a lifelong vaccine” (Chilean Woman, 66 years old).

Study participants who reported being informed about vaccines also cited several key dissemination channels: the internet, social media platforms, and pharmacies. In the case of social media, it was relevant when older people consulted their younger relatives, whose recommendations were often based on content found in informal media groups, rather than on health authorities’ official information. Formal health sector channels were also reported, with study participants receiving information during routine health check-ups at the health clinics. Also, participants affiliated with private healthcare providers highlighted email communications as an important means of informing them about vaccination periods.

“On the radio or on television. That, and sometimes I read a little more, too. I Google information there. Now that we have so many ways to search the internet for more precise information, when I have a question or concern or curiosity, let’s say, to know a little more. And also, there are many ways to search for information now” (Chilean Man, 74 years old).

“At the clinic, they gave me all the information through a brochure. They explained the vaccine they were giving, what type of vaccines they were, and what number they were given, because they were sort of numbered. They gave me all the options at the clinics” (Chilean Woman, 65 years old).

Perceptions regarding the overall vaccination process showed variation, related to factors such as age, living arrangements, independence, and awareness of the PNI. In this context, there was a group of older study participants who reported being self-sufficient and able to attend vaccination appointments independently; some were even responsible for managing the vaccination schedule of others. However, in cases where a family member accompanied them to receive the vaccine, it was typically them who assumed responsibility for staying informed and keeping up with the vaccination schedule. For individuals residing in long-term care facilities, vaccines were administered on-site. Also, known cases were described of older study participants living alone, lacking support networks, and being unable to access vaccination centers. Most of the migrant study participants described receiving very good care, and in several cases expressed surprise at having been treated no differently than the national population.

“It has been very effective as far as I have seen, the nurses, the doctors, the students, everything has been very, very effective. When I have gone to get vaccinated, I have seen the lines there are and they always let people like me, who use a wheelchair, go first, and that is something very nice, very good that they have because there is preference for those of us who have trouble with our legs. And I have really appreciated that here -truly, in Chile because I have seen many good things, the way everyone treats you, even those who do the cleaning in the hospitals. I can testify that they are kind, good people, very caring, very different from what I was used to seeing” (Migrant Man, 81 years old).

Barriers and facilitators to accessing the national vaccination program for older adults

Based on study participants’ experiences and perceptions, six main barriers to accessing the national vaccination program for older adults were identified: (i) Limited dissemination and low awareness of the pneumococcal vaccine; (ii) Fear of adverse events and effects about receiving multiple vaccines and multiple shots within short timeframes; (iii) Health conditions, understood by participants as having one or more chronic illnesses perceived to be incompatible with vaccine administration; (iv) Mobility or health-related issues that hinder commute to vaccination centers; (v) Barriers associated with social vulnerability, such as poverty and financial inability to attend vaccination sites; and (vi) Specific barriers affecting the migrant population, particularly the perception that access to health services and vaccination is not possible without a provisional Chilean´s national ID, experiences of discrimination and mistreatment, and the belief that the public health system is overwhelmed due to the presence of migrants.

“I’m left wondering whether they might cause an adverse reaction in a person for whom it isn’t appropriate — someone who has hypertension, or an underlying condition that makes things complicated.” (Chilean Woman, 69 years old).

“Vaccination is free, but there are people who can’t get there. Maybe because they live so far away, they have no way to communicate or to travel. Many times, they live so far away that no cars or anything else can get through, and they don’t have any other means of transportation. For example, right here in Santiago, there are areas where I know they have no way to get out” (Migrant Woman, 70 years old).

“It can also be an obstacle if you’re not registered or don’t have your papers, so you can’t get vaccinated. (…) Well, it wasn’t easy for me to register early at a health center, and they don’t even give you a provisional ID number, and it becomes a bit complicated to get vaccinated.” (Migrant Woman, 65 years old).

From our analysis, we identified four main facilitators that were perceived to trigger vaccination uptake among older adults in Chile according to study participants. While the first three facilitators were shared across both Chilean and migrant participants, the fourth was specific to the migrant group: (i) the availability of vaccination centers within short distances across the territory; (ii) the provision of quality care and respectful treatment, particularly for older individuals; (iii) the presence of robust vaccination campaigns led by the national health authority; and (iv) for the migrant population specifically, a set of recommended actions to improve information dissemination and strengthen the strategy, including: informing about the availability of free vaccines regardless of migration status; ensuring respectful treatment; providing healthcare and vaccination services without requiring a provisional national ID; and guaranteeing dignified, high-quality care free from discrimination and stigma, with no differential treatment and control compared to the national population.

“The care is wonderful. The two women treated me well yesterday. Time, location, and space factors. I don’t know what kind of factor I could… I find the entire system favorable. You know where the vaccination center is, and all access is easy. It’s convenient and practical” (Migrant Woman, 67 years old).

“I’ve always, always been satisfied with the team, with the people. I find that they’re very well-disposed and do their job well. I’ve never had a traumatic or negative experience, or that the person who gave it to me was difficult. On the contrary, they always give you instructions on how to take care of yourself afterward, to drink plenty of fluids, put some ice on it” (Chilean Woman, 69 years old).

" I haven’t had any problems. Whenever I’ve been called in, I’ve been vaccinated, so everything has been, I can say, everything has been correct. There’s been very good care, and I think yes, everything is very good. I believe it’s the same for everyone, both Chileans and any foreigners, not just Peruvians, for anyone. As I said before, I’ve helped many people get there, and I haven’t heard that there’s been any case where, because they’re foreigners, they haven’t been treated well. No, everything has been normal for everyone.” (Migrant Man, 72 years old).

Recommendations for increasing vaccination uptake among older people

Drawing from the study findings, the research team identified four main recommendations: (i) Strengthen the quality and accessibility of official, evidence-based information. In particular, enhance education from an early age regarding the benefits of vaccination, provide more comprehensive and in-depth information about vaccination, beyond simply announcing immunization periods, and address negative myths surrounding them; (ii) Increase dissemination and awareness of the pneumococcal vaccine and reinforce vaccine-related information through media and commercial spaces frequented by older adults; (ii) Implement follow-up and educational initiatives targeting older adults who have not yet been vaccinated; (iii) Expand home-based vaccination services for individuals unable to attend health centers; (iv) For the migrant population specifically, improve information strategies including language translation, with a focus on those who have recently arrived in the country; and enhance the treatment of migrants, who may experience discrimination or mistreatment.

“We should strengthen awareness, advertising, and information campaigns a little more. And not just say that these vaccines are available, on a certain date, and for these people, but also explain again why it’s good to get vaccinated, let’s say, in each case, whether it’s for older adults, because we can get the flu and maybe end up with pneumonia, and that leads to death. Or for young children, explain clearly why they also need to get vaccinated with the different vaccines they receive at different times. Not just perhaps advertise it, but also explain again why, why the body needs these supports. What would happen if we don’t give these vaccines to children? Or what would happen if we adults don’t get them? Explain, explain why it’s good to do so” (Chilean Man, 74 years old).

“Go to the people who can’t get there, have the municipality take the person with their vehicles so they can get vaccinated” (Chilean Woman, 80 years old).

" I would say that there’s a lack of awareness or sensitivity among health personnel regarding the way foreigners are treated… it’s a much bigger problem than just the health system itself, but one would expect that at least in healthcare there would be good, respectful treatment.” (Migrant Woman, 65 years old).

Discussion

Main findings and their interpretation

Chile’s PNI plays a pivotal role in the country’s public health system. Its effectiveness is largely attributed to high national coverage rates, underpinned by a well-established logistical system and strong institutional integration. Nevertheless, during and after the COVID-19 pandemic, certain knowledge gaps remain -particularly concerning the experiences and perceptions of older adults, both local and migrant, in accessing vaccination services. This demographic often requires tailored communication, education, and support strategies. The present study sought to explore these experiences for locals and migrant older populations, with a specific focus on identifying perceived barriers and facilitators to vaccination in three major urban centers in Chile.

The findings indicate the presence of a well-established vaccination ethos in Chile, with older adults generally adhering to the national immunization schedule. Nonetheless, several perceived barriers and facilitators to vaccine access were identified, stemming from both the healthcare system (supply side) and the older population (demand side), as well as from the dynamics of their interaction within healthcare settings. Notably, experiences of mistreatment or perceived discrimination were particularly salient among some older migrant study participants, whereas Chilean participants more frequently cited concerns about adverse effects and the overlap of multiple vaccines as barriers to uptake. It is important to note that neither Chilean nor migrant participants constituted a homogeneous group; within-group diversity in experiences and perceptions was evident. These barriers underscore the urgent need for improved communication strategies, targeted information campaigns, and strengthened community-based approaches tailored to the needs of older adults. Special attention should be given to subgroups such as migrants, individuals living alone, residents of long-term care facilities, and those dependent on younger relatives. Developing effective educational strategies to promote vaccination uptake among older people requires a nuanced understanding of the specific perceptions, needs, and obstacles faced by these populations, especially in light of the rapid aging of the population in Chile and other emerging and industrialized nations.

We identified notable commonalities in participants’ general perceptions of Chile’s vaccination program for older adults, including shared recognition of its contribution to population health and preventive care. However, substantial differences emerged regarding attitudes toward specific vaccines and between Chilean-born adults and international migrants. The observed similarities may, in part, reflect the fact that all participants resided in large urban centers, where vaccination services, infrastructure, and governance structures are relatively accessible and well developed [53, 54]. Conversely, heterogeneity between individuals and groups is likely greater than what our study could capture, as perceptions of immunization are shaped by a complex interplay of personal life histories, cultural belief systems, and prior interactions with health providers, as well as exposure to information and misinformation circulating through traditional and social media [55–57].

Comparison with previous studies

Our findings align with international research showing that low adherence to vaccination schedules among older adults remains a significant public health concern globally. Vaccine hesitancy -driven by misinformation, fear of adverse effects, concerns about safety, and barriers to accessing vaccination services- continues to be a major obstacle to immunization in this population [58–60]. These concerns are often intensified by limited access to reliable health information, particularly among underserved older people groups such as migrants and rural communities [61]. Structural challenges such as fragmented healthcare systems, inconsistent communication from providers, and logistical difficulties further hinder vaccine uptake [62]. Socioeconomic and health status barriers, including poverty, multimorbidity and transportation limitations, also contribute to missed vaccination opportunities [59]. Addressing these multifaceted challenges requires integrated strategies that combine culturally sensitive education, improved provider-patient communication, and systemic reforms to ensure equitable access to vaccines for older adults [59, 63].

In Latin America, older adults face a range of barriers that hinder equitable access to vaccination, many of which are shaped by structural, social, and behavioral determinants. Studies have shown that fragmented healthcare systems, limited integration of services, and geographic disparities contribute to under-vaccination in this population [64]. Additionally, vaccine hesitancy, often driven by misinformation, low health literacy, and fear of adverse effects, is exacerbated by inconsistent communication from healthcare providers and a lack of culturally appropriate outreach strategies [65–67]. Among migrant and socioeconomically disadvantaged older adults, administrative obstacles such as the requirement for national identification documents, as well as logistical challenges like transportation and long wait times, further restrict access to immunization services [68]. The World Health Organization emphasizes the importance of understanding behavioral and social drivers of vaccine uptake, recommending tailored interventions that address both demand- and supply-side barriers [69]. These findings underscore the need for region-specific strategies that incorporate community engagement, improved provider-patient communication, and systemic reforms to ensure equitable vaccine access for older adults across Latin America.

In our study we were able to identify at least six unique barriers to accessing vaccination schemes according to older people, encompassing low awareness of the pneumococcal vaccine, fears of adverse events and concerns about receiving multiple vaccines in short intervals, perceptions of chronic illnesses as incompatible with immunization, mobility and health-related limitations affecting travel to vaccination sites, socioeconomic vulnerabilities that restrict the ability to attend services, and migrant-specific obstacles, including lack of a provisional national ID, experiences of discrimination, and beliefs that an overburdened public health system limits their entitlement to care. Research on barriers to vaccination among older migrants in LATAM reveals significant structural, legal, and sociocultural challenges that vary across countries [60]. In Mexico, undocumented older migrants often face exclusion from public health programs due to their legal status and lack of documentation, which limits access to vaccines even during public health emergencies like COVID-19 [70]. In Brazil, despite the existence of a universal health system (SUS), older migrants encounter language barriers, discrimination, and bureaucratic obstacles that hinder timely vaccination, particularly in rural and underserved regions [71]. In Colombia, the mass arrival of Venezuelan migrants has overwhelmed health services, and older adults frequently lack access to immunization due to fragmented registration systems and limited outreach strategies [72]. These barriers are compounded by misinformation, fear of side effects, and mistrust in institutions, which are prevalent among migrant communities across the LATAM region [70]. Moreover, traditional immunization schedules in LATAM often prioritize children and pregnant women, leaving older migrants outside the scope of routine campaigns [70]. The literature emphasizes the need for culturally sensitive communication, community engagement, and inclusive health policies to improve vaccine uptake among this vulnerable population. Tailored interventions, such as mobile vaccination units and multilingual health education, have shown promise but remain underutilized [71].

An emerging public health concern identified in this analysis is the reliance of older adults on younger family members for vaccine-related decision-making, particularly when the older individuals lack sufficient information or confidence in their own judgment. This dynamic becomes problematic when younger relatives themselves are influenced by misinformation circulating on social media platforms. Studies show that older adults are especially vulnerable to health misinformation due to cognitive decline and increased emotional sensitivity, which can impair their ability to critically assess online content [73]. Moreover, younger individuals often serve as informal health advisors within families, and their exposure to misleading or sensationalist content on platforms like Facebook, TikTok, or WhatsApp can inadvertently shape the health decisions of older relatives [74]. The “better safe than sorry” principle observed among older adults—where they prefer to trust potentially false information to avoid perceived health risks -further amplifies the impact of misinformation [73]. Public health campaigns, such as the U.S. “We Can Do This” initiative, have demonstrated that multi-channel media strategies can improve vaccine uptake, but they also highlight the need for targeted interventions that address intergenerational information flows and digital literacy [75]. To mitigate this issue, public health systems must implement consistent, culturally sensitive, and evidence-based communication strategies that not only reach older adults directly but also equip younger family members with accurate information and critical thinking tools.

Strengths and limitations

This study presents both strengths and limitations. As a qualitative inquiry, it offers rich insights into the multifaceted and context-dependent factors that shape older adults’ experiences with vaccination. By employing in-depth interviews and thematic analysis, the research captures personal narratives, cultural frameworks, and emotional dimensions that are often overlooked in quantitative approaches, thereby contributing to a deeper understanding of risk perception and trust in healthcare systems [76, 77]. Nonetheless, the study’s relatively small sample size limits its generalizability and may not fully reflect the diversity of experiences among older individuals across different socioeconomic, ethnic, and geographic backgrounds in the three urban settings examined [78]. Additionally, the use of snowball sampling through community leaders’ networks may introduce selection bias, potentially skewing the findings toward more socially connected participants [76, 79]. Despite these methodological constraints, this research represents one of the first qualitative efforts in Chile to explore vaccination attitudes and barriers among older adults, offering valuable groundwork for future hypothesis generation and culturally responsive interventions [80]. Importantly, the study addresses a critical gap in the literature by amplifying the voices of older adults, including marginalized groups such as migrants, who often encounter compounded challenges in accessing and accepting vaccines. Future investigations should consider longitudinal designs, participatory research frameworks, and culturally tailored strategies to enhance the relevance and impact of public health policy and practice.

Implications for policy and practice

This study adds to the growing body of public health research and policy by addressing a critical gap in Chilean scholarship: the limited qualitative exploration of vaccine hesitancy among older adults. While global evidence increasingly recognizes the complexity of immunization decision-making in later life [77], Chilean research has yet to fully examine how intersecting factors -such as migration status, multimorbidity, financial hardship, and regional inequalities- shape vaccine-related perceptions and behaviors in older populations [77]. These gaps indicate the need for locally grounded, interdisciplinary research that actively involves older adults and their support networks as co-creators of knowledge and policy responses. The implications for policy are significant. First, the lack of culturally and contextually relevant data calls for the integration of participatory approaches in health policy design, ensuring that interventions reflect the lived realities of diverse older populations [81, 82]. Second, policies should reinforce the role of primary care providers and official health authority social media channels as trusted sources of vaccine information. This effort must be supported by training in culturally sensitive communication and shared decision-making to counter misinformation and build institutional trust [83, 84].

Conclusions

This study suggests that older study participants in urban Chile generally trusted the national immunization program, yet important gaps persist in awareness -particularly of pneumococcal vaccination- and in access among those with limited mobility, socioeconomic vulnerability, or migrant status. Key barriers included insufficient information, personal concerns about adverse effects, and structural and cultural obstacles, while accessible vaccination sites, supportive healthcare interactions, and visible public campaigns facilitated uptake. Improving timely, culturally responsive communication and strengthening provider training on the needs and rights of diverse older populations are essential to advancing equitable immunization coverage. These findings are relevant to other LATAM countries as many jurisdictions, despite their differences in income and socio-political context, share a historical culture of value for vaccination programs, complex migration trends and health systems challenged by structural limitations and diverse needs, perceptions and experiences of the population they serve.

Authors' contributions

BC, AO, PM, AB, MS, and AC made substantial contributions to the conception, design of the work; the acquisition, analysis, and interpretation of data; have drafted the work or substantively revised it; have approved the submitted version (and any substantially modified version that involves the author’s contribution to the study); and have agreed both to be personally accountable for the author’s own contributions and to ensure that questions related to the accuracy or integrity of any part of the work, even ones in which the author was not personally involved, are appropriately investigated, resolved, and the resolution documented in the literature. EMH have drafted the work and substantively revised it; have approved the submitted version (and any substantially modified version that involves the author’s contribution to the study); and have agreed both to be personally accountable for the author’s own contributions and to ensure that questions related to the accuracy or integrity of any part of the work, even ones in which the author was not personally involved, are appropriately investigated, resolved, and the resolution documented in the literature.

Funding

MSD Equity grant, which has applied to and granted by an external reviewing committee.

Data availability

Semi-structured interview guide is available. Full transcripts of interviews can be provided upon request (all anonymized).

Declarations

Ethics approval and consent to participate

The study was conducted in accordance with the appropriate guidelines and regulations for research involving human beings, including the Declaration of Helsinki. It received approval from the Scientific Ethics Committee at Universidad del Desarrollo before its execution. All participants read and signed an online informed consent.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.