Twenty Years of Progress and the Way Forward: Immunization Registry Information System in Korea

Abstract

The National Immunization Program in The Republic of Korea offers mandatory and free vaccinations to children under 12, regulated by the Infectious Disease Prevention and Control Act. Tracking vaccination coverage is crucial for population protection and public health strategies. Since 2002, the Immunization Registry Information System (IRIS) has been used nationwide to capture vaccination data. This study reviewed documents related to IRIS’s establishment and development. The Republic of Korea legally supports IRIS's construction and data collection, integrating vaccination data with the Ministry of the Interior and Safety's resident registration to minimize errors. This collaboration also facilitates cost reimbursement and digital registration, promoting wider vaccination coverage. IRIS manages expense claims once vaccination details are logged, and authorized medical institutions can access these records in real-time. Since 2015, the Korea Disease Control and Prevention Agency has been compiling annual data on national vaccination coverage. IRIS also sends automated reminders in 12 languages, reports adverse effects, and issues vaccination certificates. However, IRIS lacks integration between vaccine and disease registries, unlike countries such as England, Denmark, and the Netherlands. Improving integration capabilities could enhance IRIS's support for public health through an integrated information system.

INTRODUCTION

Vaccination is the most cost-effective method for the prevention of infectious diseases, reducing both the incidence and mortality rates of infections.1,2,3,4,5 By obstructing the transmission of target infectious diseases, vaccination safeguards both individuals and communities from illness. A high vaccination coverage is essential for managing Vaccine-Preventable Diseases, and to attain the effects of herd immunity, a vaccination coverage of 80–95% or higher must be maintained.6,7 The Republic of Korea's National Immunization Program (NIP) is a structured initiative grounded in the Infectious Disease Prevention and Control Act (IDPCA). It mandates routine vaccinations for targeted infectious diseases, focusing on children aged 12 and under.8,9 The program includes 18 types of vaccines and adherence to a specific vaccination schedule is required.10 Vaccinations are administered at public health centers or designated medical institutions, and the costs are supported by the central and local governments.8,11

Successfully managing vaccination programs, which involves ensuring many people get vaccinated smoothly, requires a well-organized and accurate approach. A vaccination register system is crucial for this, as it helps healthcare providers keep track of vaccinations for different groups of people and make sure they get their shots on time.12,13 This real-time tracking ensures comprehensive coverage, optimizes the effectiveness of vaccines through timely administration, and fosters transparent and accurate reporting.14,15 Moreover, the register system aids in supply chain management, avoiding shortages and wastages, and enhances public trust and compliance through transparent and accessible vaccination records.12,16

To achieve the imperative goals of comprehensive vaccination coverage and seamless program implementation, the Republic of Korea initiated the Immunization Registry Information System (IRIS) in 2002.17 In this article, we aim to review the principal characteristics of the IRIS in the Republic of Korea, reflecting on its development history and conducting a comparative analysis with similar systems in other countries. Additionally, we will propose potential pathways and strategic recommendations for its future advancement.

METHODS

The research employed a retrospective design, focusing on a comprehensive review of documents and records associated with the initial establishment and preparatory stages of the IRIS. Specifically, the study drew from data starting from the year 2000, a period marking the initial stages of the IRIS’s development. The primary sources for data collection included foundational documents, developmental records, early-stage communications, and other pertinent documents that outlined the initial undertakings and considerations surrounding the system. Additionally, the vaccination coverage rates for various years were derived directly from the IRIS.

Given the study’s qualitative nature, the approach to data analysis was thematically oriented. Records and documents were coded systematically to identify and categorize key milestones and decisions integral to the inception of IRIS. The review of the document followed a protocol based on Hanney et al.,18 which was tailored to suit the objectives of the research. This thematic coding facilitated a deeper understanding, enabling the construction of a detailed narrative about the system's origins, objectives, and the initial challenges it encountered.

RESULTS

Overview of IRIS

The Republic of Korea has built the IRIS on a strong legal framework. It gathers vaccination data nationwide in real-time to track coverage. This system connects with different data sources to improve efficiency and accuracy. It also has features like sending reminders, reporting side effects, and issuing vaccination certificates.

The legal foundation for IRIS in the Republic of Korea ensures that personal data collection is lawful, addressing privacy concerns. The collected information is well protected by law. The IDPCA mandates the establishment and operation of a vaccination registration system. This system helps efficiently process, record, and manage data needed for vaccination tasks. Unlike other countries where vaccination computer registration might be implemented only in specific states or regions,19,20,21 the Republic of Korea’s system allows for national data that facilitates easy tracking of vaccination coverage and personal identification, thereby ensuring nationally represented data reliability. Prior to the implementation of the IRIS, vaccination records were individually managed by each health center or medical institution, leading to challenges in obtaining accurate vaccination information due to scattered information and management negligence.17 With the implementation of IRIS, vaccination records previously managed separately by each medical institution have now been digitized and standardized. This consolidation allows for a comprehensive view of individual vaccination histories, greatly aiding in assessing vaccination timeliness and coverage. Additionally, upon registering vaccinations, private medical institutions participating in the NIP become eligible for government reimbursement of vaccination expenses.22

The system promotes timely vaccination by providing advance notice of vaccination timing and offers automated Reminder and Recall services to notify individuals of missing vaccination information, thereby guiding and encouraging adherence to the recommended vaccination schedule.10 In the IRIS, information such as the name of the vaccination recipient, resident registration number (nationally accredited personal identification number), types and names of vaccines, vaccine lot numbers, and vaccination dates are provided.23 Based on this information, the system supports text message services to the guardians of vaccination recipients regarding their child's next vaccination or any missing vaccinations. Additionally, it offers a reporting framework that allows for the reporting of any adverse effects following vaccination.24 Moreover, the system also provides a feature to issue a vaccination certificate, which can be essential for instances such as overseas travel or study abroad when documentation of vaccination records is required.25,26

The IRIS has been developed incrementally to incorporate these features. Initially applied exclusively to public health centers, the IRIS was then progressively expanded to encompass private clinics from 2004.27 As time passed, the Korean government realized the importance of improving the system even more. They upgraded it to include a database connection with the Korea Disease Control and Prevention Agency (KDCA), which includes the infectious disease reporting system. This upgrade centralized crucial health data. Moreover, they added new features like a reminder recall service, offering both healthcare providers and patients important tools for staying on track with vaccinations. Starting from 2009,28 the vaccine register system was further expanded to have more linkages with different government organizations such as the Ministry of Education and the Ministry of the Interior and Safety. This cross-organizational integration facilitates a comprehensive understanding of the population's health and educational status, thereby creating an optimized and more informed approach to immunization.23 This progressive development is illustrated as a milestone in Fig. 1.

Fig. 1. History of IRIS expansion.

IRIS = Immunization Registry Information System.

Real-time vaccination coverage

Vaccination records stored in the computer systems of public health centers or designated medical institutions can be accessed in real-time by any medical facility, provided that personal information is confirmed. This makes it easier to confirm and manage upcoming vaccination schedules. Within the IRIS system, these computerized vaccination records allow for various conditions such as location, gender, birth year, and vaccination age to be selected for verifying vaccination status. Furthermore, the data stored in the vaccination registration system serves as the basis for the annual announcement of national children's vaccination coverage status, which helps monitor vaccination coverage at national, provincial, and municipal levels. This data is crucial for preventing infectious diseases that can be prevented through vaccination and evaluating the NIP.

The first national vaccination coverage surveys conducted in 2011 and 2013 involved telephone interviews with 7,000 three-year-old children. Starting in 2015, the KDCA began using their computerized vaccination registration system, IRIS, to compile annual statistics on national vaccination coverage. In contrast to the phone-based surveys of 2011 and 2013, the "National Vaccination Coverage" for 2015 and 2016 was calculated for all 3-year-olds through IRIS. This usage of IRIS has been progressively broadened: it covered ages 1–3 in 2017, and then both ages 1–3 and 6 in 2018.29 By the year 2022, The Republic of Korea’s vaccination coverage for children, particularly those aged 1 year old, was observed to be 96.1%, as illustrated in Fig. 2.

Fig. 2. National vaccination coverage for children aged 1 to 3 years in Korea. One-year-old: BCG 1, HepB 3, DTaP 3, IPV 3, Hib 3, PCV 3; 2-year-old: BCG 1, HepB 3, DTaP 4, IPV 3, Hib 4, PCV 4, MMR 1, VAR 1; 3-year-old: BCG 1, HepB 3, DTaP 4, IPV 3, Hib 4, PCV 4, MMR 1, VAR 1, HepA 2, IJEV 3 or LJEV 2. The number of vaccines may vary when calculating the vaccination rate by year because the inclusion timing in the National Immunization Program differs for each vaccine.

BCG = intradermal Bacille Calmette-Gúerin vaccine, HepB = hepatitis B vaccine, DTaP = diphtheria and tetanus toxoids and acellular pertussis vaccine adsorbed, IPV = inactivated poliovirus vaccine, Hib = haemophilus influenzae type b vaccine, PCV = pneumococcal conjugate vaccine, MMR = measles, mumps, and rubella vaccine, VAR = varicella vaccine, HepA = hepatitis A vaccine, IJEV = inactivated Japanese encephalitis vaccine, LJEV = live Japanese encephalitis vaccine.

Vaccination cost reimbursement

As shown in Fig. 3, the vaccination cost reimbursement scheme is systematically structured to collect real-time registration data and provide incentives to private medical institutions. In the Republic of Korea, public health centers or designated medical institutions administer mandatory vaccinations free of charge to children under the age of 12. Following vaccination, health centers register the vaccination in the IRIS, while medical institutions document the vaccination using the Electronic Medical System or directly in IRIS. To prevent duplicate or incorrect vaccinations, it is recommended to computer-register the vaccination on the same day it is administered. When designated medical institutions register vaccination records in the computer system after administering a vaccination, the IRIS automatically applies for vaccination costs, considering the recipient’s age, intervals between previous vaccinations, etc. Public health centers overseeing the recipient's address verify compliance with vaccination execution standards and pay the costs to the medical institution through IRIS. If any unjustified claims for costs occur due to non-compliance with the execution standards at a medical institution, the health center may refuse to pay.

Fig. 3. Vaccination cost reimbursement scheme.

PHIS = public healthcare information system, KDCA = Korea Disease Control and Prevention Agency, EMR = electronic medical record.

The Republic of Korea is leveraging this medical institution cost reimbursement system to encourage both an increase in vaccination coverage and more active computer registration.22 In the Republic of Korea, both medical institutions and the guardians of those receiving vaccinations have the ability to check computer-recorded vaccination details via the government-operated "Vaccination Assistant" website. When there is a need for vaccination certificates, they can be sourced from public health centers or medical institutions. Additionally, guardians can independently issue these certificates in either Korean or English through the “Vaccination Assistant” website (https://nip.kdca.go.kr).

Minimization of human error by data linkage

The personal information of vaccination recipients is linked with the resident registration population of the Ministry of the Interior and Safety in the Republic of Korea, allowing for the verification of an individual’s residency status and death information within the system at the time of computer registration of vaccination records. In the event of a recipient’s death, the registration of vaccination records is restricted to dates following the death, thus ensuring data reliability.29

Furthermore, when vaccination institutions create new personal information for vaccination recipients and register their vaccination history, they can also verify residency status, address changes, and any errors in the resident registration number. If the resident registration number is found to be incorrect, the institution contacts the relevant guardian to reconfirm and correct the information through an established procedure.29,30 The verification of these changes in personal information is done by matching the registered vaccination records with resident registration data from the Ministry of the Interior and Safety the next morning.30 Fig. 4 describes the flow of vaccination information within The Republic of Korea’s public health infrastructure. The Ministry of Food and Drug and the Health Insurance Review and Assessment Service (HIRA) provide vaccine information. This information is utilized by the KDCA and public health centers and medical institutions for vaccination registration and public communication. The Ministry of Education accesses vaccination data for students through its Education Information System, while the Ministry of Health and Welfare leverages health and social security systems to manage health data. This not only reduces human errors but also elevates the accuracy and quality of the vaccination registry data.

Fig. 4. Immunization Registry Information System data flow chart.

Programmed reminder and recall messages

Guardians of children eligible for mandatory vaccinations are guided through mobile text messages about the scheduled vaccination time according to the standard vaccination schedule, thus facilitating timely vaccinations.29 “Remind” messages are sent to those who have agreed to receive advance notifications. Since 2010, IRIS has been used as a tool to send reminder text messages. After 2016, support was extended for the recall service and expanded to cover 12 foreign languages, including Nepali, Lao, Russian, Mongolian, Vietnamese, English, Uzbek, Japanese, Chinese, Cambodian, Thai, and Filipino. This allows guardians, who are foreigners not proficient in Korean, to receive advance notifications in their desired language.31,32

“Recall” provides information on delayed vaccinations to guardians if a vaccination is delayed by one month or more compared to the standard vaccination schedule, ensuring that no vaccinations are missed. The Reminder/Recall service is automatically sent at the designated notification time from the IRIS, and this function serves as an essential means to enhance the vaccination coverage.33 Due to the implementation of a robust reminder and recall system, NIP coverage was sustained at an elevated level throughout the coronavirus disease 2019 pandemic, thereby reinforcing the resilience of the NIP.29,34

DISCUSSION

The IRIS in the Republic of Korea emerges as a pioneering exemplar in the domain of vaccination information management. Founded upon a sturdy legal framework of nationwide applicability, it offers manifold benefits, particularly when juxtaposed with analogous systems in other countries. A notable forte of IRIS resides in its robust legal basis, which guarantees the lawful acquisition of personal data and instills a palpable sense of confidence regarding data confidentiality. This facet assumes paramount significance given the prevalent privacy apprehensions encountered by numerous nations in the realm of data collection.35 Such challenges can compromise the effectiveness of their immunization registry systems. The ability of IRIS to provide an integrated, nationwide perspective, unlike systems confined to specific regions, assures a comprehensive understanding of vaccination coverage, crucial for crafting informed health initiatives.20,21 Another noteworthy advantage lies in the utilization of personal identifiers, enabling seamless real-time electronic data transmission. This capability allows IRIS to dynamically update information for various events such as births, relocations, or child mortality, affording it a discernible edge over traditional systems. This real-time feature addresses persistent challenges like unregistered populations.12,23 It ensures health officials have the most recent demographic data, refining vaccine coverage and the precision of interventions.

The implementation of national-scale real-time coverage parallels approaches adopted in other nations. Countries like Denmark, the Netherlands, Australia, and Norway have pioneered similar real-time coverage systems.14,15,36,37 Systems comparable to IRIS, operational in these nations, are pivotal in directing vaccination policies and ensuring broad immunization coverage. This underlines the universal significance of real-time data accessibility.

Moreover, the multifaceted features of IRIS, encompassing real-time accessibility, proactive notifications regarding impending vaccinations, automated reminders, multilingual recall services, and other functionalities, cater to a broad demographic, effectively meeting the diverse requirements of the Republic of Korea’s population. Its seamless integration with resident registration data from the Ministry of Interior and Safety notably mitigates human errors, thereby enhancing the system’s overall reliability.23

However, one of the areas where IRIS falls short is its interconnectivity between vaccine registers and disease registers. Currently, IRIS does not have a robust integration with the disease register. Due to the management of immunization data and disease information by different entities—vaccination by the KDCA, and health insurance claim data correlated with the disease registry by HIRA and National Health Insurance Service—and restrictions under personal information protection laws, data linkage was previously limited. By contrast, nations like England, Denmark, and the Netherlands can evaluate vaccine effectiveness through a tight-knit linkage between vaccine and disease registers.14,19,36 The Danish vaccination register integrates data from multiple sources, including prescription databases and the national health insurance system. Additionally, it gathers relevant data from various administrative registers, providing comprehensive information about vaccinators, vaccines, and the vaccines used.14 The England’s Child Health Information Systems (CHISs) cover the population up to 18 years old, based on birth health registration. These computerized clinical record systems support child health prevention programs, including vaccinations. Through CHISs, disease and vaccine data are automatically linked and used for evaluating vaccine effectiveness.19 In the Netherlands, Præventis, the national immunization registry for children under 19, is integrated with the Interdisciplinary Processing of Clinical Information, a population-based medical record database, enabling monitoring of vaccination effectiveness and safety.36 Assessing vaccine efficacy is crucial for shaping public health strategies, and the current gap in IRIS could result in missed opportunities for timely interventions and adjustments of vaccination programs based on real-world outcomes. Establishing data linkage with the disease registry would bolster surveillance of vaccine adverse reactions, significantly enhancing safety monitoring efforts. This linkage would enable proactive and simultaneous monitoring of safety issues. Furthermore, it’s imperative to provide feedback on reported cases to individuals, such as physicians, to enhance their understanding of vaccine safety.

IRIS holds significant potential for further development. One promising avenue involves integrating child health screening data with the vaccine registry. This integration would provide a comprehensive overview of a child’s health, allowing healthcare professionals to tailor vaccination schedules to individual needs. For instance, children identified with specific vulnerabilities during health screenings may require customized vaccination timelines or additional doses to ensure enhanced protection.12 Given the higher non-registration rate of vaccination among non-NIP targeted individuals such as adults, enhancing registration for them is necessary.38 Expanding the current system, which is mainly for the NIP's beneficiaries, to include these individuals and vaccinations outside the program will allow for better management of vaccinations and enable monitoring of nationwide vaccination rates in real-time.

In conclusion, IRIS stands as a benchmark in vaccination information management, underpinned by its robust legal framework and real-time capabilities. Its achievements reflect global best practices in the field. However, the ongoing quest for enhancement highlights areas for further refinement, particularly in bolstering integration with disease registries. As IRIS progresses along its evolutionary trajectory, integrating it with disease data holds transformative potential, offering a more personalized and effective approach to immunization. This ensures that Korea's health priorities are met with steadfast precision and foresight.