Abstract
Objectives
The 23-valent pneumococcal polysaccharide vaccine (PPSV23) is included in the routine immunisation programme for adults aged 65 years and those aged 60–64 years with serious chronic medical conditions (CMCs). To improve the vaccination coverage rates, a catch-up subsidy programme was implemented by the Japanese government from October 2014 to March 2024, which resulted in no improvement in the coverage rates. For further facilitation of pneumococcal vaccination, research is warranted to understand public attitudes toward pneumococcal vaccination by assessing coverage rates and reasons for vaccination among not only the subsidy-eligible population but also in individuals aged 19–64 years with CMCs who self-pay for pneumococcal vaccination.
Design
Nationwide, cross-sectional survey.
Setting
A web-based questionnaire study using a validated consumer panel in Japan.
Participants
Japanese adults aged 19–64 years with CMCs and those aged ≥65 years registered in the consumer panel as of March 2023.
Primary and secondary outcome measures
Vaccine coverage rates, reasons for receiving or not receiving the vaccination, willingness of unvaccinated individuals to receive the vaccine in the future under the current vaccination programme and factors associated with pneumococcal vaccination coverage rates.
Results
Vaccination coverage rates were 12.4% in those aged 19–49 years, 3.2% in those aged 50–59 years and 4.0% in those aged 60–64 years with CMCs and 55.1% in those aged ≥65 years (61.6% and 52.9% in those with and without CMCs, respectively). The majority (89.1%) of unvaccinated participants aged 19–64 years with CMCs had a positive or neutral attitude towards receiving future pneumococcal vaccinations. Among vaccinated individuals, 79.0% of those aged 19–64 years with CMCs and 56.0% of those aged ≥65 years reported that they had received a doctor’s recommendation. Doctors’ recommendation was the most common reason for receiving the vaccine among participants aged 19–64 years with CMCs (35.1%), whereas notification from the municipality was the most important reason among those aged ≥65 years (46.1%).
Conclusions
Data from this study suggest that recommendations from doctors are crucial for increasing coverage rates of pneumococcal vaccines, particularly among adults aged 19–64 years with CMCs. The majority of unvaccinated participants in this group had a positive or neutral attitude towards future vaccination, highlighting the importance of strong recommendations by doctors.
Trial registration number
jRCT1030220606.
Keywords: Vaccination, Chronic Disease, Surveys and Questionnaires, Immunization Programs
STRENGTHS AND LIMITATIONS OF THIS STUDY.
Our study assessed pneumococcal vaccination rates both among individuals eligible for the subsidy programmes and among those who self-paid for vaccines outside of the vaccination programme, providing a more comprehensive understanding of vaccination coverage in Japan and capturing a broader spectrum of vaccination behaviours.
Although the study participants were drawn from a validated consumer panel and may not fully represent the general population in Japan, the distribution of individuals across the eight Japanese regions was similar to that in the overall Japanese population, enhancing the generalisability of our findings to a national context.
While our study’s self-reported data may have limitations in accuracy regarding the presence of chronic medical conditions, vaccination status and type of pneumococcal vaccines administered, engaging directly with the target population allowed us to capture their genuine insights behind their vaccination decisions, offering a richer understanding of the factors influencing vaccination uptake beyond statistical associations.
Introduction
Streptococcus pneumoniae is a gram-positive bacterium that colonises the mucosal surfaces in the upper respiratory tract, forming a reservoir that enables transmission.1 When S. pneumoniae invades sterile sites, it can cause pneumococcal disease, which can lead to serious invasive infections such as bacteraemic pneumonia, meningitis and bacteraemia.1,3 Invasive pneumococcal disease (IPD) is a leading cause of morbidity and mortality among children and adults in Japan.4 5 According to the National Epidemiological Surveillance of Infectious Diseases, the number of IPD cases has increased every year, with 2.53 cases per 100 000 in the general population in 2017.3 Infection occurs most commonly in risk groups, including young children aged <5 years (9.47 cases/100,000 population) and the elderly aged ≥65 years (5.38 cases/100,000 population).3 Between 2018 and 2021, children aged <5 years accounted for 15.4%–20.0% of the total cases, whereas adults aged ≥65 years accounted for 57.2%–60.6% of the total cases in Japan.6 Three pneumococcal vaccines are currently available in Japan: the 23-valent pneumococcal polysaccharide vaccine (PPSV23), the 15-valent pneumococcal conjugate vaccine (PCV) and the 20-valent PCV.6 7 In addition, the 21-valent PCV (PCV21), designed to target serotypes affecting adults, is currently under review for regulatory approval in Japan.8 While pneumococcal disease can be prevented with pneumococcal vaccination in most cases, these vaccines only protect against disease caused by the serotypes of S. pneumoniae included in each formulation.
Pneumococcal vaccination of the elderly using PPSV23, as part of the National Immunization Program (NIP), was initiated in 2014 in Japan.3 7 Additionally, vaccination for individuals aged 60–65 years who have heart, kidney or respiratory disorders or immunity-related disorders caused by HIV is also offered as part of the immunisation programme.3 However, the reported pneumococcal vaccination coverage rate among individuals eligible for the NIP has been low, with the rate being <40% despite the implementation of the NIP since 2014.9,11
Some factors affecting the pneumococcal vaccination coverage rate among the elderly have been found to be the availability of local government subsidies and lack of individual notifications by the local government. When individuals have to pay for their own vaccinations, vaccination coverage rates remain low; moreover, access to suitable information about eligibility is essential to increase vaccination rates.12 Furthermore, a recent study (the LIFE study) assessed the vaccination coverage rates of pneumococcal vaccination in the population aged ≥65 years using vaccination records between April 2014 and March 2020 in two municipalities in Japan. The LIFE study showed that women, those in higher income ranges, those with ≥1 hospital visit per month and those participating in specific health check-ups (a medical examination recommended once a year for people aged 40–74 years) were more likely to be vaccinated.11
The transitional catch-up subsidy programme was introduced to increase the NIP vaccination coverage rate for the pneumococcal vaccine among the elderly. The first round of this programme ran from 2014 to 2019, followed by a second round implemented in 2019 for an additional 5 years, aiming to provide vaccination opportunities for those who had not previously received any vaccination.13 However, this transitional programme has ended, and as of April 2024, individuals aged >65 years are no longer eligible for routine vaccinations.14
Individuals of all ages who have chronic medical conditions (CMCs) are at an increased risk of developing pneumococcal diseases, such as IPD. Additionally, individuals with multiple comorbidities are at an even greater risk than those with a single comorbidity.7 15 16 Nevertheless, PPSV23 vaccination coverage rates among adults aged 50–60 years with CMCs are notably low,9 and there is a lack of vaccination registration in Japan.
Besides policies on recommendations regarding who should receive the vaccine and whether there are subsidies for receiving it, factors such as vaccine hesitancy, lack of knowledge about the vaccine and the risk and seriousness of IPD may affect the vaccine coverage rates in at-risk populations.17 Therefore, research investigating the most up-to-date coverage rates of the pneumococcal vaccine and factors that may affect the coverage rates is warranted to inform future policies and education campaigns regarding pneumococcal vaccination to overcome barriers to vaccination.18
To determine the pneumococcal vaccination coverage rate in populations at risk in Japan, we performed a nationwide, web-based, cross-sectional survey (jRCT1030220606) among Japanese individuals aged 19–64 years with CMCs and those aged ≥65 years with and without CMCs who received their vaccination either as part of the NIP or self-paid. Furthermore, to determine the main reasons for and barriers to vaccination, we asked participants what their real-life attitudes were towards vaccinations by obtaining self-reported reasons in these groups for receiving or not receiving the vaccination and the willingness of unvaccinated adults with CMCs to receive future pneumococcal vaccinations under the current NIP as measured in March 2023.
Methods
Sample and data
This questionnaire survey was conducted between 6 March 2023 and 15 March 2023. The questionnaire was developed in Japanese by the authors and distributed to 559 807 individuals registered in a consumer panel owned by Macromill Carenet, Inc. (Tokyo, Japan), which includes approximately 5 million anonymously registered Japanese citizens. A translated version of the questionnaire is provided in online supplemental data 1. A flowchart of the study survey is presented in online supplemental figure S1. Eligibility for participation was assessed using screening questions to include the first 5100 individuals aged 19–64 years with CMCs and 2000 individuals aged ≥65 years who met the inclusion criteria described below. Recruitment for each group was terminated when responses from the required number of participants set for that group were obtained.
Adults aged 19–64 years with CMCs or those aged ≥65 years who were willing and able to answer an internet-based survey were included in this study. All survey participants self-reported the presence of underlying conditions listed below: chronic heart disease (eg, congestive heart failure, arrhythmia, heart attack), chronic lung disease (eg, chronic obstructive pulmonary disease, emphysema, asthma), diabetes mellitus, chronic liver disease (eg, hepatitis, cirrhosis), chronic kidney disease (eg, nephritis, kidney failure), cerebrospinal fluid leakage, cochlear implant, autoimmune disease (eg, rheumatoid arthritis, collagen vascular diseases), HIV infection (AIDS), cancer, organ or stem cell transplantation and anatomical or functional asplenia. Participants who had at least one of the aforementioned underlying conditions were considered as having CMCs. No exclusion criteria were defined.
All survey participants provided online informed consent to participate in this study. This study involves human participants and was approved by the ethics review committee of the Fuji Keikai Kitamachi Clinic on 18 January 2023 (approval number: MSD09322).
Measures of variables
The primary outcome was pneumococcal vaccination coverage rates in the Japanese population aged 19–64 years with CMCs and the population aged ≥65 years with and without CMCs. Secondary outcomes included the reasons for receiving or not receiving the vaccination and the willingness of unvaccinated individuals to receive the vaccine in the future under the current vaccination programme as measured in March 2023. Furthermore, we determined the factors associated with pneumococcal vaccination coverage rates and compared the pneumococcal vaccination coverage rates between various age groups, between various CMCs and between those aged ≥65 years with and without CMCs.
Data analysis procedure
The sample size (5100 adults aged 19–64 years with CMCs and 2000 adults aged ≥65 years) was set to achieve a half-width of the 95% CI for the coverage rate of 0.8%–1.3% and 1.3%–2.1%, respectively, assuming a vaccination coverage rate of 10.0%–40.0%.
The survey responses were summarised using descriptive statistics. A multivariable logistic regression analysis was performed to analyse the factors that may affect the pneumococcal vaccination coverage rate. The respondents were separately included in two multivariable analyses: one for adults aged 19–64 years with CMCs and the other for the elderly aged ≥65 years. Prior to model analysis, correlations between any two covariates were investigated. To avoid multicollinearity, only one of the two variables was included in the candidate covariates for a model when the correlation was >0.8. We originally planned the model analysis to include only those participants who were aware of the pneumococcal vaccine. However, to minimise the collider bias, a model analysis including all participants was performed as a post hoc analysis. In this study, the latter regression results are reported. A total of 25 covariates were included in the regression model, and variables with the largest p values >0.5 were excluded in order in each step until a sufficient number of covariates was selected for the final model. Eventually, 24 covariates were selected for participants aged 19–64 years with CMCs, and 14 covariates were selected for participants aged ≥65 years. In the subgroup analyses for each group, the ORs of specific categories compared with those of the reference category in each subgroup variable were estimated with the corresponding 95% CI based on each multivariable logistic regression model.
All statistical analyses were performed using SAS V.9.4 or higher (SAS Institute Inc., Cary, North Carolina, USA) and R V.4.3.0 (The R Foundation, Vienna, Austria).
Patient and public involvement
Patients or the public were not involved in the design, conduct, reporting or dissemination plans of our research.
Results
Survey respondents
Survey responses were obtained from 5100 individuals with CMCs aged 19–64 years (1700 each in the age groups 19–49 years, 50–59 years and 60–64 years; men, 3062 individuals (60.0%)) and 2000 individuals aged ≥65 years (men, 1000 individuals (50.0%); 513 with CMCs and 1487 without CMCs; table 1). The mean (SD) ages were 39.5 (7.5), 54.7 (2.9) and 62.0 (1.4) years for those aged 19–49 years, 50–59 years and 60–64 years with CMCs, respectively. The mean (SD) age was 74.6 (6.1) years for those aged ≥65 years, with 75.7 (6.1) and 74.2 (6.0) years for those with and without CMCs, respectively. Only a subset of individuals did not receive the influenza vaccine (28.5% of those aged 19–64 years with CMCs and 25.8% of those aged ≥65 years), and the majority received COVID-19 vaccination (90.5% of those aged 19–64 years with CMCs and 93.7% of those aged ≥65 years; online supplemental table s1 and figure S2). A visual overview of the study design and key findings, summarising the study hypothesis and major outcomes, is also present in online supplemental appendix 1.
Table 1. Demographic data of the study participants.
| Parameter | Category | Age 19–64 years with CMCs | Age ≥65 years | |||||
|---|---|---|---|---|---|---|---|---|
| Total | Age 19–49 years | Age 50–59 years | Age 60–64 years | Total | Age 19–49 years | Age 50–59 years | ||
| N (%) | n (%) | n (%) | n (%) | N (%) | n (%) | n (%) | ||
| All participants | 5100 (100) | 1700 (100) | 1700 (100) | 1700 (100) | 2000 (100) | 513 (100) | 1487 (100) | |
| Sex | Male | 3062 (60.0) | 660 (38.8) | 1079 (63.5) | 1323 (77.8) | 1000 (50.0) | 323 (63.0) | 677 (45.5) |
| Female | 2038 (40.0) | 1040 (61.2) | 621 (36.5) | 377 (22.2) | 1000 (50.0) | 190 (37.0) | 810 (54.5) | |
| Age (years) | 19–49 | 1700 (33.3) | 1700 (100.0) | – | – | – | – | – |
| 50–59 | 1700 (33.3) | – | 1700 (100.0) | – | – | – | – | |
| 60–64 | 1700 (33.3) | – | – | 1700 (100.0) | – | – | – | |
| 65–69 | – | – | – | – | 500 (25.0) | 97 (18.9) | 403 (27.1) | |
| 70–74 | – | – | – | – | 500 (25.0) | 122 (23.8) | 378 (25.4) | |
| 75–79 | – | – | – | – | 535 (26.8) | 140 (27.3) | 395 (26.6) | |
| ≥80 | – | – | – | – | 465 (23.3) | 154 (30.0) | 311 (20.9) | |
| Living area | Hokkaido | 307 (6.0) | 116 (6.8) | 103 (6.1) | 88 (5.2) | 97 (4.9) | 27 (5.3) | 70 (4.7) |
| Tohoku | 301 (5.9) | 124 (7.3) | 100 (5.9) | 77 (4.5) | 73 (3.7) | 22 (4.3) | 51 (3.4) | |
| Kanto | 1864 (36.5) | 584 (34.4) | 628 (36.9) | 652 (38.4) | 858 (42.9) | 200 (39.0) | 658 (44.3) | |
| Chubu | 861 (16.9) | 300 (17.6) | 274 (16.1) | 287 (16.9) | 273 (13.7) | 74 (14.4) | 199 (13.4) | |
| Kinki | 912 (17.9) | 269 (15.8) | 327 (19.2) | 316 (18.6) | 456 (22.8) | 128 (25.0) | 328 (22.1) | |
| Chugoku | 267 (5.2) | 108 (6.4) | 80 (4.7) | 79 (4.6) | 86 (4.3) | 23 (4.5) | 63 (4.2) | |
| Shikoku | 135 (2.6) | 39 (2.3) | 49 (2.9) | 47 (2.8) | 33 (1.7) | 8 (1.6) | 25 (1.7) | |
| Kyushu | 453 (8.9) | 160 (9.4) | 139 (8.2) | 154 (9.1) | 124 (6.2) | 31 (6.0) | 93 (6.3) | |
CMC, chronic medical condition.
Pneumococcal vaccination coverage rates
Among individuals aged 19–64 years with CMCs, the pneumococcal vaccination coverage rate was low across all age groups (12.4% for those aged 19–49 years, 3.2% for those aged 50-59 years and 4.0% for those aged 60–64 years; figure 1). The vaccination coverage rate was 55.1% in individuals aged ≥65 years and higher among those with CMCs than among those without CMCs (61.6% vs 52.9%; figure 1).
Figure 1. Pneumococcal vaccine coverage rates among included age groups. CMC, chronic medical condition.
Among those aged 19–64 years with CMCs, the vaccination coverage rate was <20% in those with diabetes (5.6%), chronic lung disease (13.0%), chronic heart disease (7.1%), chronic liver disease (12.2%), chronic kidney disease (15.1%), autoimmune diseases (7.6%) and cancer (6.0%; figure 2A). On the other hand, among individuals aged ≥65 years with CMCs, the vaccination coverage rates (60.9%–100%) for each CMC category were higher than those detected in the group aged 19–64 years (figure 2B). The group aged 19–49 years with CMCs had a higher proportion of autoimmune diseases and chronic lung diseases than those with CMCs aged 50–59 years or 60–64 years (online supplemental figure S3).
Figure 2. Pneumococcal vaccination coverage rates by comorbidities. (A) Individuals aged 19–64 years with CMCs. (B) Individuals aged ≥65 years with CMCs. Multiple choices were allowed for CMCs. *As the number of eligible individuals was limited, caution is advised when interpreting the data. No cases of AIDS, cochlear implant, CSF leakage or spleen removal/no spleen were included in the age ≥65 years group. CMC, chronic medical condition; CSF, cerebrospinal fluid; SCT, stem cell transplant.
The majority of individuals aged 19–64 years with CMCs and those aged ≥65 years who received a pneumococcal vaccine were vaccinated with the PPSV23 vaccine, and only a small proportion of individuals received the PCV13 vaccine (online supplemental figure S4).
Doctors’ recommendation for pneumococcal vaccination and reasons for receiving or not receiving pneumococcal vaccination
Most individuals who received the pneumococcal vaccine reported that their doctors recommended receiving the pneumococcal vaccine (79.0% and 56.0% for those aged 19–64 years with CMCs and those aged ≥65 years, respectively; figure 3). In contrast, among individuals who had not received the pneumococcal vaccine, only 4.3% and 8.4% of those aged 19–64 years with CMCs and those aged ≥65 years, respectively, had received a doctor’s recommendation for pneumococcal vaccination (figure 3).
Figure 3. Doctors’ recommendation for pneumococcal vaccination. (A) Individuals aged 19–64 years with CMCs. (B) Individuals aged ≥65 years. CMC, chronic medical condition.
The most common reason for receiving the pneumococcal vaccine was doctors’ recommendation (35.1%) in individuals aged 19–64 years with CMCs and notifications from the municipality (46.1%) in individuals aged ≥65 years (online supplemental table S2). The most common reason for not receiving the pneumococcal vaccine was a misunderstanding of the eligible age for pneumococcal vaccinations (39.8%) in individuals aged 19–64 years with CMCs and feeling healthy and not needing vaccination (26.5%) in those aged ≥65 years (online supplemental table S2).
Willingness of unvaccinated individuals aged 19–64 years with CMCs or aged ≥65 years with or without CMCs to receive future pneumococcal vaccinations
Among the 1893 unvaccinated respondents aged 19–64 years with CMCs, 824 (43.5%) had a positive attitude and 864 (45.6%) had a neutral attitude towards future pneumococcal vaccinations (online supplemental figure S5A). The proportion of unvaccinated respondents with a positive attitude towards future pneumococcal vaccinations increased with age (39.0% for those aged 19–49 years, 40.8% for those aged 50–59 years and 50.2% for those aged 60–64 years; online supplemental figure S5A). In the group aged ≥65 years, 43.2% of the unvaccinated respondents had a positive attitude toward future pneumococcal vaccinations under the current vaccination programme as measured in March 2023, with similar proportions for those with CMCs (43.6%) and those without CMCs (43.0%; online supplemental figure S5B).
Factors that may affect the pneumococcal vaccination coverage rate
Among individuals aged 19–64 years with CMCs, female sex (OR=0.62, 95% CI (0.176 to 0.246), p=0.005) and advanced age (50–59 years: OR=0.33, 95% CI (0.100 to 0.144); 60–64 years: OR=0.36, 95% CI (0.116 to 0.172), p<0.001 for both) were identified as factors potentially leading to lower pneumococcal vaccination rates. Smoking (‘every day’: OR=2.43, 95% CI (0.669 to 0.925), p<0.001; ‘sometimes’: OR=4.78, 95% CI (1.809 to 2.908), p<0.001), alcohol consumption (‘every day’: OR=2.01, 95% CI (0.631 to 0.921), p<0.001; ‘sometimes’: OR=1.43, 95% CI (0.410 to 0.575), p=0.041), lower body mass index (<18.5 kg/m2: OR=1.79, 95% CI (0.640 to 0.997), p=0.010), self-evaluated health status (‘very good’: OR=3.00, 95% CI (1.297 to 2.287), p<0.001 and ‘good’: OR=1.50, 95% CI (0.459 to 0.663), p=0.031) and exercise habits (‘every day’: OR=3.04, 95% CI (0.975 to 1.434), p<0.001; ‘sometimes’: OR=2.13, 95% CI (0.619 to 0.872), p<0.001) were identified as factors potentially leading to increased pneumococcal vaccination rate (online supplemental figure S6A). Furthermore, the presence of influenza vaccination history and comorbidities, except for cerebrospinal fluid leakage, were identified as factors potentially leading to increased pneumococcal vaccination rates. The highest OR was observed for organ transplant/haematopoietic stem cell transplant (OR=22.74, 95% CI (15.079 to 44.769)), spleen removal/asplenia (OR=18.34, 95% CI (14.267 to 64.183)) and AIDS (OR=5.97, 95% CI (3.912 to 11.356); online supplemental figure S6A).
Among individuals aged ≥65 years, female sex (OR=1.27, 95% CI (0.248 to 0.308), p=0.031) and advanced age (70–74 years: OR=1.29, 95% CI (0.311 to 0.411), p=0.074; 75–79 years: OR=1.39, 95% CI (0.336 to 0.443), p=0.020) were identified as factors potentially leading to increased pneumococcal vaccination rates (online supplemental figure S6B). Furthermore, exercise habits (‘every day’: OR=1.99, 95% CI (0.478 to 0.629), p<0.001; ‘sometimes’: OR=1.57, 95% CI (0.328 to 0.415), p<0.001) and history of influenza vaccination (‘this year and every year’: OR=4.97, 95% CI (1.121 to 1.448), p<0.001; ‘this year and some years but not all’: OR=2.63, 95% CI (0.831 to 1.213), p<0.001; ‘not this year but sometimes’: OR=2.35, 95% CI (0.631 to 0.862), p<0.001) were identified as factors potentially leading to increased pneumococcal vaccination rates (online supplemental figure S6B). No clear trend was observed for smoking status in this group; compared with nonsmokers, those who smoked every day were less likely (OR=0.67, 95% CI (0.212 to 0.309), p=0.040) and those who smoked sometimes were more likely (OR=1.47, 95% CI (0.874 to 2.156), p=0.404) to be vaccinated for pneumococcal disease (online supplemental figure S6B).
Knowledge about pneumococcal vaccines and risks of pneumococcal infections and source of information about the pneumococcal vaccine
In total, 43.6% of individuals aged 19–64 years with CMCs and 77.0% of those aged ≥65 years were aware of the adult pneumococcal vaccination programme (online supplemental figure S7). Nevertheless, the majority of those who knew about the vaccination programme did not know about the types of vaccines available (63.1% of individuals aged 19–64 years with CMCs and 63.1% of those aged ≥65 years; online supplemental figure S7).
The main sources of information regarding the pneumococcal vaccine varied based on age and vaccination status. Among the unvaccinated adults, the most common source of information was mass media for both the groups aged 19–64 years (54.0%) and ≥65 years (43.6%). Among those vaccinated and aged 19–64 years with CMCs, doctors or nurses (67.3%) were the most common sources of information. Among those vaccinated and aged ≥65 years, notifications from the local government (55.9%) were the most common sources of information (online supplemental figure S8).
The majority of respondents who were aware of the existence of the pneumococcal vaccine recognised pneumonia as a serious illness (87.6% of individuals aged 19–64 years with CMCs and 91.8% of individuals aged ≥65 years); however, the number of individuals who recognised their own risk of pneumococcal infection was limited (46.7% of individuals aged 19–64 years with CMCs and 31.5% of individuals aged ≥65 years; online supplemental figure S9). Compared with individuals who received the pneumococcal vaccine in the group aged 19–64 years, those who did not receive the vaccine were less likely to assume that they were at risk (42.4% vs 70.9%) and less likely to consider the vaccine to be safe (41.2% vs 67.3%). Compared with individuals who received the pneumococcal vaccine in the group aged ≥65 years, those who did not receive the vaccine were less likely to consider the vaccine to be safe (34.9% vs 71.4%), important for adults (46.3% vs 84.9%), a good method for protecting their health (55.9% vs 88.3%) and important for a person with chronic diseases (59.1% vs 80.5%; online supplemental figure S9).
Discussion
In this study, we conducted a nationwide survey to assess the pneumococcal vaccination coverage rate in the Japanese population aged 19–64 years with CMCs and the population aged ≥65 years with and without CMCs. The vaccination coverage rate of the pneumococcal vaccines was 55.1% and 6.5% in the population aged ≥65 years and those aged 19–64 years with CMCs, respectively.
The vaccination coverage rate of 55.1% in the elderly population detected in this study was higher than that reported in the LIFE study (33.6%) for the same age group.11 This difference may be attributed to variability in the study population and the methodology used to collect data. In our study, we assessed a population in multiple areas across Japan and collected self-reported data from individuals who were aware of the pneumococcal vaccine, rather than relying on vaccination records. In addition, this study did not solely rely on vaccination rates for a single year; rather, it closely approximated the cumulative vaccination rate. It examined the vaccination status from the introduction of the NIP in 2014 through 2023 to confirm the presence or absence of pneumococcal vaccination over time.
The vaccination coverage rate of the pneumococcal vaccine in individuals aged ≥65 years with CMCs increased slightly after a previous patient survey performed in 2018 (from 54.9% in 2018 to 61.6% in 2023), suggesting that the programme was successful for this group.9 However, as previously mentioned, this study closely approximated the cumulative vaccination rates. With an additional 5 years of data compared with the previous study’s 2018 data, it is reasonable to expect an increase in the number of vaccinated individuals aged ≥65 years with CMCs. Nevertheless, the overall coverage rate for individuals aged ≥65 years (55.1%) was still lower than that reported in the USA (67.5%), suggesting the need for improvements in the vaccination programme.19
We detected a remarkably low (6.5%) pneumococcal vaccination coverage rate in individuals with CMCs aged 19–64 years, despite their increased vulnerability to pneumococcal diseases. The coverage rate among individuals aged 50–59 years and 60–64 years showed a slight increase but remained low after our previous patient survey conducted in 2018 (from 1.3% and 2.9% in 2018 to 3.2% and 4.0% in 2023, respectively).9 However, it should be noted that the 2018 pneumococcal vaccine coverage rate established for those aged 50–64 years included PPSV23 rates only,9 whereas our study included all available pneumococcal vaccines at the time of the survey (PPSV23 and PCV13). We found that individuals aged 19–49 years with CMCs had a higher vaccination coverage rate (12.4%) than those aged 50–59 years (3.2%) and 60–64 years (4.0%). This may be due to the higher proportion of individuals with diseases associated with high vaccination rates, such as individuals with chronic lung disease, autoimmune diseases, organ transplant or stem cell transplant and AIDS (HIV infection), in this group than in other age groups.
We also assessed the reasons why unvaccinated participants did not receive the vaccine and their views on receiving potential future vaccination. Our data suggested that a lack of understanding of the risks associated with pneumococcal infections may be contributing factors to the low coverage rate. A recent study in Japan among patients with rheumatoid arthritis suggested that vaccine hesitancy might be due to concerns about the safety of the vaccine.20 We also found that participants who were unvaccinated were more likely to not consider the vaccine to be safe. However, the proportion of unvaccinated respondents with a positive attitude towards future pneumococcal vaccinations increased with age among those aged 19–64 years with CMCs.
Additionally, we assessed the main reasons for receiving the vaccine among our study populations. Most vaccinated individuals aged 19–64 years with CMCs received a recommendation for the pneumococcal vaccine from their doctors. This aligns with the findings from other studies that individuals who had more frequent hospital visits or participated in specific health check-ups tended to have higher coverage rates.11 21 Furthermore, a history of influenza vaccination and exercise habits were positively associated with having received the pneumococcal vaccine. This aligns with previous research in which pneumococcal vaccination was associated with exercise habits and receiving influenza vaccinations.9 22 23
Greater awareness of the associated risks and recommendations from doctors can have a positive impact on coverage rates.23,26 Given that doctors serve as the primary source of information for the pneumococcal vaccine, they will play a crucial role in informing and recommending the vaccine to individuals aged 19–64 years with CMCs, even if it requires out-of-pocket expenses. Financial support for individuals aged 19–64 years with CMCs may be crucial as financial barriers are likely to deter patients from getting vaccinated and may also influence doctors’ willingness to recommend vaccination. Providing subsidies or financial assistance could help increase vaccine uptake and encourage more proactive recommendations from doctors. This dual approach has the potential to improve vaccination rates, reduce health risks, promote healthcare equity and enhance public health outcomes.
Although our study did not specifically analyse the influence of family or internet-based information, previous research in Japan has shown that family members can play an important role in vaccination decisions, particularly for influenza.27 Given this cultural context and the absence of notifications from local governments, future public health strategies aiming to improve pneumococcal vaccination uptake among individuals aged 19–64 years with CMCs may benefit from approaches that involve family support and use internet-based communication channels.
Our data showed that notifications and subsidies from the local government for the pneumococcal vaccine were the major reasons for vaccination among adults aged ≥65 years. These individuals also relied on the local government as their main source of information about the pneumococcal vaccine. A previous study has also shown that receiving notifications about the vaccine greatly contributes to achieving higher vaccine coverage rates.12 Furthermore, previous studies have noted the financial cost of the vaccine as a barrier,12 23 and the LIFE study indicated that higher-income individuals were more likely to be vaccinated, suggesting that subsidies may play an important role in improving vaccination rates.11 It is important to note that once the transitional catch-up programme is completed and only individuals aged 65 years are eligible for pneumococcal vaccination subsidy from April 2024 onwards, a significant decrease in vaccination coverage is expected in Japan.14 Therefore, it is crucial for local governments to actively inform those aged 65 years about the pneumococcal vaccine, ensuring that they take advantage of the opportunity to receive vaccination as part of the subsidy programme.
To enhance pneumococcal vaccination uptake among adults in Japan, strategies should focus on motivating doctors, as doctors’ recommendations strongly influence patients’ decisions. Simplifying vaccination schedules and introducing vaccines with greater impact can also facilitate doctors’ recommendations by reducing complexity and improving perceived vaccine effectiveness. Research in the US suggests that pneumococcal vaccine formulations tailored to the serotypes causing disease predominantly in adults, rather than using the same vaccines designed for children, should be prioritised to optimise protection and programme effectiveness.26 The recent approval and Advisory Committee on Immunization Practices recommendation of PCV21 for adults represents an advancement in adult pneumococcal disease prevention, offering broader serotype coverage and improved cost-effectiveness compared with previous vaccines.28 Incorporating PCV21, which requires only a single dose and targets serotypes most relevant to adult IPD, into adult immunisation programmes may have a strong potential to increase doctors’ motivation to recommend vaccination, especially for adults with CMCs or other risk factors. This, in turn, could lead to higher vaccine uptake and a meaningful reduction in the pneumococcal disease burden in this vulnerable population.
Study limitations
A strength of this study is that it included not only vaccines obtained through subsidy programmes but also self-paid vaccines outside of the vaccination programme, thereby providing a more comprehensive understanding of vaccination coverage in Japan. Additionally, by directly engaging with the target population, we captured their genuine insights into the reasons behind their vaccination decisions. However, our study has several limitations. First, this study did not assess the impact of COVID-19 on pneumococcal vaccination. Second, the type of pneumococcal vaccines available and covered by the subsidy programmes in Japan has changed after the conduct of this study. Another limitation of this study was the representativeness of the participants and potential selection bias, which are commonly observed in any web-based surveys. Of note, the distribution of individuals in our study population among the eight Japanese regions was generally similar to that in the overall Japanese population. Furthermore, the self-reporting of CMCs may have resulted in an underestimation of the percentage of each CMC or the number of CMCs. The vaccination status and type of pneumococcal vaccines (PPSV23 or PCV13) were also self-reported and may, therefore, be inaccurate if participants remembered their status incorrectly without the vaccination report data. Finally, our study focused on participants who were aware of the pneumococcal vaccine. This focus may have led to an underestimation of vaccination rates, as it excluded individuals who received the vaccine without knowing its specific designation. Conversely, it may have also resulted in an overestimation of vaccination rates, as those who were aware of the vaccine were likely to have received it, whereas those unaware were likely to have not received it, thus being excluded from the analysis. Nonetheless, this approach enabled us to obtain valuable insights from an informed group regarding their perceptions and decision-making processes concerning pneumococcal vaccination.
Conclusion
In conclusion, this study revealed low pneumococcal vaccination coverage rates among adults aged 19–64 years with CMCs and the population aged ≥65 years with and without CMCs. This was a survey study that reflected the participants’ real voices and included their views on vaccination, reasons for getting vaccinated and willingness to receive future vaccination. Our data suggest that the main reasons for the low coverage rate were a lack of knowledge about the vaccine and the perceived risk of pneumococcal disease among those eligible for the vaccine. Doctors’ recommendations were also found to have a significant influence on vaccination rates.
The study emphasises the importance of addressing vaccination barriers, such as lack of awareness, misconceptions and insufficient information, in order to improve pneumococcal vaccination coverage, especially among high-risk populations. To support this, doctors should educate and recommend the pneumococcal vaccine to eligible individuals, including those aged 65 years eligible for the NIP, those aged ≥66 years and those aged 19–64 years with CMCs, who may need to pay for vaccination out-of-pocket. By providing information about the vaccine, doctors can help patients make informed decisions about their health and potentially increase vaccination rates and reduce the burden of pneumococcal diseases in Japan.
Supplementary material
Acknowledgements
The authors thank Shuichiro Sakamoto and Yukari Ohta of MSD K.K., Tokyo, Japan, for their substantial contributions to the study. The web-based survey was operated by Shinobu Araya of Macromill Carenet Inc., Tokyo, Japan, and statistical support was provided by Ayako Shoji of Healthcare Consulting Inc., Tokyo, Japan. The authors also thank Maartje Wouters, PhD, of Cactus Life Sciences (part of Cactus Communications) for providing medical writing support, which was funded by MSD K.K., Tokyo, Japan, in accordance with the Good Publication Practice (GPP) guidelines (http://www.ismpp.org/gpp3).
Footnotes
Funding: This work was funded by MSD K.K., Tokyo, Japan (award/grant number: NA). The funder of the study was involved in the development of the study design, data collection, data analysis, data interpretation, the writing of the report and the decision to submit for publication.
Prepublication history and additional supplemental material for this paper are available online. To view these files, please visit the journal online (https://doi.org/10.1136/bmjopen-2024-098133).
Provenance and peer review: Not commissioned; externally peer reviewed.
Patient consent for publication: Consent obtained directly from patient(s).
Ethics approval: This study involves human participants and was approved by the ethics review committee of the Fuji Keikai Kitamachi Clinic on 18 January 2023 (approval number: MSD09322). Participants gave informed consent to participate in the study before taking part.
Data availability free text: The participants of this study did not give written consent for their data to be shared publicly; hence, due to the sensitive nature of the research, supporting data are not available.
Patient and public involvement: Patients and/or the public were not involved in the design, conduct, reporting or dissemination plans of this research.
Author note: KK is the Deputy Director of the NTT East Izu Hospital, located in Shizuoka prefecture, Japan. He obtained his MD and PhD degrees from Nagasaki University. As a practicing clinician in the Department of Internal Medicine, he specialises in infectious diseases and respiratory disorders. His clinical research is primarily dedicated to adult vaccinations, with a specific focus on the pneumococcal vaccines.
Data availability statement
No data are available.
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