Policy and practice of checking vaccination status at school in 2018, a global overview.

BACKGROUND: Checking vaccination status at school is widely recommended as a strategy to strengthen routine childhood vaccination coverage. Documentation of approaches, challenges, strengths, and impact of this strategy in a variety of contexts is key to enhancing adoption and implementation. However, there is limited information about the prevalence of policies and the implementation of checking vaccination status at school globally.
METHODS: A one-time supplementary survey was circulated with the annual World Health Organization (WHO) and United Nations International Children's Emergency Fund (UNICEF) Joint Reporting Form in 2019 to all WHO member states and non-member state reporting entities. Additional publicly available country-level data, including primary school enrollment, home-based record (HBR) ownership, and World Bank income classification were linked to the supplementary survey responses, which were descriptively analyzed.
RESULTS: We received survey responses from 130 of the 194 (67%) WHO member states and 15 non-member state reporting entities. Almost half (46%) of the respondents reported having a law requiring proof of vaccination to enter at least one level of education, and 60% of the respondents reported having a law that requires checking vaccination status at school in 2018. Three-quarters of the respondents (77%) reported the practice of routinely checking vaccination status at school. Both laws and the practice of checking were more common in the WHO Region of the Americas and the WHO European Region, and in high- and upper-middle-income countries. Individual HBR was the document most frequently checked. Catch-up vaccination occurred most frequently at health centers. Evaluation of checking vaccination status at school to determine what has worked and its effect was infrequently reported.
CONCLUSION: Despite widespread implementation of checking vaccination status at school in 2018, documentation of the experiences in planning and implementing this strategy, and its effects remains sparse, particularly in low- and middle-income countries.

Background

A widely recommended strategy at global, regional, and national levels to improve routine vaccination coverage is the use of school settings to check students’ vaccination status[1], [2], [3], [4]. These vaccination checks may occur when children enroll in school, begin schooling, or sometime during the school year, either in childcare, preschool, primary school, intermediate school, or secondary school settings (henceforth collectively ‘checking vaccination status at school’). Checking vaccination status at school can be an important touchpoint to identify children who have not yet received all doses of vaccines recommended on the national immunization schedule. It provides the opportunity to receive (catch-up) missed vaccine doses; thereby, increasing coverage and enhancing population immunity to vaccine-preventable diseases (VPD). It also has the potential to improve the completeness of immunization data, promote home-based record (HBR) retention, and strengthen cooperation between health and education sectors[5]. Global strategic plans for the elimination of measles and rubella, and maternal and neonatal tetanus highlight the role schools can play in checking students’ vaccination status, which has the potential to help achieve and sustain the elimination of these VPDs[6], [7].

A comprehensive school-based approach to deliver immunization services and augment vaccination coverage in school-age children is aligned with the Immunization Agenda 2030 (IA2030) strategic priority to develop vaccination platforms across the life-course[8]. School vaccination checks can be a way of operationalizing a law or policy mandating vaccination for school entry, where these exist. Alternatively, a requirement to check vaccination status at school may exist without a requirement to be vaccinated to attend school; such approaches provide an opportunity for catch-up vaccination and to understand individual vaccination status in the event of a VPD outbreak.

Most available evidence about the effectiveness of checking vaccination status in schools currently comes from high-income countries (HIC) and middle-income countries (MIC). Evidence from various provinces in China illustrates that checking vaccination status at entry to kindergarten and primary school, followed by catch-up vaccines in immunization clinics led to identification and vaccination of school-aged children missing doses of childhood vaccines. Receipt of missed doses varied by vaccine type and child’s age; population immunity in all provinces increased among the cohorts of children whose vaccination status was checked[5], [10], [11], [12]. In the Republic of Korea, an expanded national immunization program and coordination between schools and health centers, using a national immunization registry and electronic communications, such as text message reminders, led to an increase in vaccination coverage among school-aged children[13], [14]. Collaboration between the health and education sectors, high net school enrollment, and the availability of accurate sources of vaccination history, such as a national registry or more commonly, home-based records (HBR) have been reported as key influencers for introducing an effective strategy of checking vaccination at school[9]. An HBR is “a health document used to record the history of health services received by an individual. It is kept in the household, in either paper or electronic format, by the individual or their caregiver and is intended to be integrated into the health information system and complement records maintained by health facilities[15].”

Prior to 2018, the prevalence of checking vaccination status at school among WHO member states was unknown. In addition, little has been documented about the types of policies and approaches to implementation, monitoring, and evaluation of this strategy. The World Health Organization (WHO) and United Nations International Children’s Emergency Fund (UNICEF) Joint Reporting Form (JRF), an annual standardized self-report questionnaire that collects information about national immunization programs from all WHO member states, had not previously included any questions about checking vaccination status at school. In 2019, the JRF was revised to include several questions about vaccination requirements for school entry and the practice of school vaccination checks. Among 192 WHO member states that provided this data for 2018, eighty-two (43%) reported having a policy requiring vaccination to enter school, and 135 (70%) reported a practice of checking vaccination status for at least one level of education[16]. To gain a more detailed understanding about the policy and practice of checking vaccination status at school, a one-time supplementary survey was circulated along with the JRF in 2019 to all WHO member states and non-member state reporting entities (henceforth, reporting entities) per WHO region discretion. In this manuscript, we report the results of this survey to provide a global overview of the country-level policy and practice of checking vaccination status at school in 2018.

Methods

Data sources and variable definitions

The primary data source was responses to the JRF supplementary survey circulated in 2019, requesting country data as of 2018. Methodology for JRF supplementary surveys has been previously described[17]. The following publicly available country-level data were linked to the JRF supplementary survey responses dataset: World Bank income classification in 2018; whether the country was eligible for support from Gavi, the Vaccine Alliance (Gavi) in 2018; net enrollment rate of children in primary education; and HBR ownership[18], [19], [20], [21], [22], [23].

For the 2018 fiscal year, countries were classified as low, lower-middle, upper-middle or high income based on World Bank classifications[18]. Using the International Standard of Classification of Education (ISCED), childcare was defined as daycare, creche, or another setting where an infant or child is cared for away-from-home prior to attending formal education. Pre-primary, also called kindergarten, refers to the level of education preceding the first formal year of schooling, usually beginning at age three through five years old. Primary school is education at the first level (primary or elementary), usually beginning at age five through seven years old. Intermediate, or middle school, usually begins at age 11 through 13 years old with a typical duration of three years. Secondary, or high school, usually begins at age 14–15 years old with a duration of four years[24]. Net enrollment rate of children in primary education was obtained from UNESCO Institute of Statistics (the most recent year available, up to 2018; defined by UNESCO as the total number of students enrolled in the theoretical age group for primary education, as a percentage of the total population in that age group)[20]. HBR ownership for children of different age groups (12–59 months) was obtained from Multiple Indicator Cluster Surveys (MICS) or Demographic and Health Surveys (DHS) (the most recent year available, up to 2018)[21], [22], [23]. While no variable in MICS captures the period that an HBR is retained by the child’s caregiver, the MICS variable “currently owning an HBR (at the time of the survey)” was chosen for primary analysis, given it was the most readily accessible and complete. High HBR ownership and high net primary school enrollment rates were defined as ≥80 percent.

Data management and analysis

We clarified the inconsistencies within individual survey responses with countries and corrected them to the extent possible given the feedback provided. JRF supplementary survey responses were prepared for analysis using SAS software Version 9.4 (SAS Institute Inc., Cary, NC, USA), which was also used for the descriptive analyses, which focused on determining the number and proportion of WHO member states that reported the policies and practices of checking vaccination status in school. The results were stratified by World Bank income level, WHO region, net proportion of children enrolled in primary school, and HBR ownership.

Two authors thematically coded the responses to each open-ended survey question, independently and inductively[25]. They compared and discussed coding results to reach a consensus on key themes emerging from these data, which were reported with the relevant quantitative data.

Results

Responses to the JRF supplementary survey about the policies and practice of checking vaccination status at school were submitted by 130 of the 194 (67%) of WHO member states (Fig. 1). Additional survey responses were received from 15 reporting entities. Surveys with at least one completed question were included in the analysis; however, not all questions were answered by all respondents so denominators for each question differed. Respondents from the WHO Region of the Americas (AMR), WHO European Region (EUR), and WHO African Region (AFR) collectively comprised 71% (104/145) of all the respondents with at least five (range 5–25) respondents from each of the remaining three WHO regions. Half (49%) of the respondents were from middle-income countries (Table 1).

Fig. 1

Total number of WHO member states who responded to questions on the WHO-UNICEF Joint Reporting Form about school immunization delivery in 2018, and the total number of respondents to the JRF supplementary survey about the policy and practice of checking vaccination status at school in 2018.

Table 1

Characteristics of respondents to the WHO-UNICEF Joint Reporting Form supplementary survey about practice of checking vaccination status at school in 2018 (N = 145, including 130 WHO member states and 15 reporting entities)

	Respondents reporting the practice of checking vaccination status at school (n = 111)	Respondents not reporting the practice of checking vaccination status at school (n = 34)
World Health Organization region n (%)
African Region (AFR) (n = 31, 21%)	15 (48)	16 (52)
Region of the Americas (AMR) (n = 37, 26%)	34 (92)	3 (8)
Eastern Mediterranean Region (EMR) (n = 5, 3%)	5 (1 0 0)	0
European Region (EUR) (n = 36, 25%)	31 (86)	5 (14)
South-East Asia Region (SEAR) (n = 11, 8%)	7 (64)	4 (36)
Western Pacific Region (WPR) (n = 25, 17%)	19 (76)	6 (24)
World Bank income category n (%)
High-income country (HIC) (n = 54, 37%)	49 (91)	5 (9)
Upper-middle-income country (UMIC) (n = 44, 30%)	38 (86)	6 (14)
Lower-middle-income country (LMIC) (n = 28, 19%)	15 (54)	13 (46)
Low-income country (LIC) (n = 19, 13%)	9 (47)	10 (53)
Net proportion of primary school enrollment n (%)
Enrollment ≥ 80% (n = 126, 87%)	97 (77)	29 (23)
Enrollment < 80% (n = 10, 7%)	5 (50)	5 (50)
No data on enrollment (n = 9, 6%)	9 (1 0 0)	0
% of children aged 12–23 months whose caregivers currently owned a home-based record of vaccination (HBR) n(%)
Currently own an HBR ≥ 80% (n = 26, 18%)	22 (85)	4 (15)
Currently own an HBR < 80% (n = 36, 25%)	16 (44)	20 (56)
No data on current HBR ownership (n = 83a, 57%)	72 (90)	8 (10)
a Three countries did not respond

Policy requiring proof of vaccination to enter school

Sixty-six (66/145, 46%) survey respondents reported currently having a law or policy requiring proof of vaccination to enter at least one level of education (i.e., primary school, secondary school). These respondents were largely in the AMR (27/66, 41%) and EUR (14/66, 21%) regions, and from high-income (29/66, 44%) and upper-middle-income (23/66, 35%) countries, and to a lesser extent in the WPR (10/66, 15%), AFR (8/66, 12%), EMR (4/66, 6%) and SEAR (3/66, 5%) regions, and lower-middle-income (9/66, 14%) and low-income (5/66, 8%) countries. Additionally, five respondents reported having this law or policy in the past but not currently. Respondents that reported immunization requirements for school entry, required on average vaccination against 10 VPDs to enter school; this was comparable across the WHO regions, but the range differed widely (Table 2). The lowest number of VPDs for which vaccination was reported to be required for school entry ranged from two in EUR to 10 in the WHO South-East Asia Region (SEAR), and the highest number ranged from 10 in SEAR to 15 in the WHO Western Pacific Region (WPR). Proof of vaccination to enter school was required most commonly for polio, diphtheria, tetanus, pertussis, and measles in the 66 countries with immunization requirements for school entry (Fig. 2).

Table 2

Mean and range of vaccine-preventable diseases for which vaccination is required to enter school among respondents reporting ever having a policy requiring vaccination to attend school (n = 66), by WHO region in 2018

WHO Region	Average number (range) of vaccine-preventable diseases for which vaccination is required to attend school, per country
AFR	11 (4–13)
AMR	11 (5–15)
EMR	10 (8–11)
EUR	10 (2–12)
SEAR	101
WPR	11 (9–13)
Globally	10 (2–15)
1All respondents in the region reported vaccinations were required against 10 VPDs.

Fig. 2

Vaccine-preventable diseases for which proof of vaccination is required for school-entry among 66 respondents in 2018.

Policy of checking vaccination status at school

Eighty-six (86/145, 59%) respondents reported currently having a law or policy about checking the vaccination status of children at school. These respondents were largely from the WHO Regions of AMR and EUR (30 and 22 countries, respectively), and high-income and upper-middle-income countries (40 and 26, respectively). Sixty-two respondents reported having a formal written document that outlined the policy or practice of checking vaccination status at school. Five respondents reported having this law or policy in the past but not currently.

Of the 63 respondents that had either a policy requiring proof of vaccination to enter school or a policy about checking vaccination status at school, half reported having established these policies between 2010 and 2018 (15 countries) or between 2000 and 2009 (15 countries). Five respondents reported establishing such laws or policies in the 1990s, eleven in the 1980s, and five in the 1970s, while laws or policies in four respondent countries predate the 1970s.

The majority (97%) of the 86 respondents who reported a law or policy about checking vaccination status at school reported that at least one of these was issued at the national level. Twenty-four respondents (24/86, 28%) reported at least one law or policy was issued at the sub-national level, and 20 respondents (20/86, 23%) reported these being issued at the local level. Respondents reported that a law or policy checking vaccination status at school was issued by the Ministry of Health (63/86, 73%), the Ministry of Education (48/86, 56%), or jointly by the Ministries of Health and Education (34/86, 40%). Seventeen respondents (17/86, 20%) noted that a law or policy about checking vaccination status at school was issued by the “government” (i.e., no specific ministry).

Forty-five respondents (45/145, 31%) reported never having had a law or policy about checking the vaccination status of children at school. Among these, 15 (15/45, 33%) respondents reported having considered introducing it at some time, including five (5/15, 33%) in AFR, four (4/15, 27%) in EUR and WPR, and one (1/15, 7%) in AMR and SEAR. One respondent noted that checking vaccination status at school was no longer a priority as the country had achieved measles elimination, while another respondent shared that a law had been drafted by their national immunization program but was rejected several times by the government.

The practice of checking vaccination status at school

One hundred eleven (111/145, 77%) respondents stated that a child’s vaccination status was routinely checked at one or more levels of the education system (Table 1), mostly in AMR and EUR (34 and 31 countries, respectively). Respondents who reported the practice of checking vaccination status at school were predominantly from either middle-income (53/145, 37%) or high-income (49/145, 34%) countries.

The proportions of respondents practicing immunization checks at school differed across the WHO regions and by country income level (Table 1). The WHO regions with the highest proportion of countries reporting this practice were WHO Eastern Mediterranean Region (EMR), AMR, and EUR; it was less commonly reported in AFR. HIC and upper-middle-income countries (UMIC) implemented this strategy more commonly than lower-middle-income (LMIC) and low-income countries (LIC), as did countries with net school enrollment ≥80% versus those with net school enrollment <80 percent. The practice was also more common in countries with higher documented availability of HBRs (≥80% versus <80%). Thirty-four (23%) respondents, representing all WHO regions, reported that there was no practice in place in their country for checking vaccination status at school. The policy and practice of checking vaccination status remain unknown for 11 (8%) WHO member states and reporting entities.

Implementation

Most respondents reported checking vaccination status at school was done at primary school (101/145, 70%), pre-primary school (89/145, 61%), or childcare (80/145, 55%), while under half reported checking at the intermediate- (64/145, 44%) or secondary- (61/145, 42%) levels of school (Fig. 3). Seventy percent (101/145) of respondents reported checking at two or more levels of education, with 44 (44/145, 30%) respondents checking at all five levels. Fourteen countries (14/145, 10%) reported checking at four levels, most commonly pre-primary through secondary schools, 24 (24/145, 17%) at three levels, most commonly daycare, pre-primary and primary schools, and 19 (19/145, 13%) at two levels, most commonly daycare and pre-primary schools. These trends were seen across the WHO regions and income categories, although the practice of checking vaccination status at the intermediate or secondary levels were most commonly reported in EURO and AMR regions as well as HIC.

Fig. 3

Level of the education system at which checking vaccination status of children at school was implemented among respondents (n = 86a) who reported ever having such a law or policy, by WHO region and World Bank income level in 2018. a More than one response was provided by single respondents, AFR = African Region, AMR = Region of the Americas, EMR = Eastern Mediterranean Region, EUR = European Region. SEAR = South-East Asian Region, WPR = Western Pacific Region, HIC = High-income country, UMIC = Upper-middle-income country, LMIC = Lower-middle-income country, LIC = Low-income country.

Eighty-three respondents (83/145, 57%) reported having both a policy of checking vaccination status at school and reported routinely implementing this practice. Both policy and practice were most commonly reported by countries in AMR (30/83, 36%) and EUR (21/83, 25%) regions, followed by WPR (12/83, 14%), AFR (9/83, 11%), SEAR (6/83, 7%) and EMR (5/83, 6%) (Fig. 4). Over three-quarters of these respondents were HIC (39/83, 47%) and UMIC (26/83, 31%). Twenty respondents reported that checking vaccination status at school was practiced without an accompanying law or policy requiring proof of vaccination prior to school entry, including six from WPR, five from EUR, and four from both AFR and AMR. These 20 respondents were mostly from UMIC (nine) and HIC (eight). Twenty-five respondents reported that vaccination status is not checked at any level of the education system, with no law or policy in place, including 12 countries in AFR and five in WPR regions; these were mostly LMIC and LIC.

Fig. 4

Relation of the policy and practice of checking vaccination status at school in 2018, by WHO region and World Bank income level (N = 145 respondents).

Individual HBR was the predominant form of immunization document checked across the WHO regions and World Bank income category, followed by certificates of vaccination issued by local health centers. Thirty-four respondents, predominantly in HIC (23 countries) and UMIC (nine countries), reported the use of electronic immunization records to check children’s vaccination status at school. The personnel conducting the checking varied by WHO region and World Bank Income category. Most commonly, school health staff and nurses checked children’s vaccination records in EMR, EUR, WPR, and HIC. It was reported that in AFR, mostly the schoolteachers, administrative staff, and local health workers checked the vaccination status of the children at school. In MIC and LIC, checking was predominantly done by the school health nurses, schoolteachers, and local health workers.

Ninety-two (92/145, 63%) respondents reported that children who missed doses were referred to the health center to receive them, either by schools or health centers notifying the caregiver that the child had been identified as missing recommended vaccine doses (Fig. 5). Twenty-two (22/145, 15%) respondents reported that missed vaccine doses were provided at school on the same day of checking, predominantly in HIC (nine) and UMIC (nine). Sixty-eight (68/143, 48%) respondents both checked and provided doses of missed vaccines at school (three respondents did not provide an answer). One of these 68 respondents added that once a child had been referred for catch-up vaccination at a health center, this information was subsequently relayed back to the school, and school staff regularly followed up with caregivers to ensure the missed vaccine doses were received.

Fig. 5

Method by which catch-up vaccination is implemented for children identified as missing vaccine doses during school vaccination checks, by WHO Region and World Bank income level, 2018 (n = 68 respondentsa), a More than one response was provided by single respondents, AFR = African Region, AMR = Region of the Americas, EMR = Eastern Mediterranean Region, EUR = European Region. SEAR = South-East Asian Region, WPR = Western Pacific Region, HIC = High-income country, UMIC = Upper-middle-income country, LMIC = Lower-middle-income country, LIC = Low-income country.

The majority (136/145, 87%) of respondents to the JRF supplementary survey had net primary school enrollment data available from UNESCO Institute of Statistics. Most respondents (126/136, 93%) with available school enrollment data had high (≥80%) net primary school enrollment.

Data on HBR ownership was available for 62 countries. Across both WHO region and World Bank Income categories among these 62 countries, the 12–23-month-old age group had the highest proportion of HBR ownership at the time of the survey compared to other age groups above 23-months of age, ranging from a median of 90% in EUR to 63% in SEAR. Availability of data on ownership of HBR, the observed proportion of surveyed children, and owning an HBR declined with the increasing age of children for which these data were collected. Countries that reported checking vaccination status at school had higher HBR ownership compared to countries that did not (Table 3). Among the 111 respondents who reported checking vaccination status at school was implemented in 2018, 95% had high HBR ownership. Among the 34 respondents who did not report the practice of checking vaccination status at school in 2018, 85% had high HBR ownership.

Table 3

Extent of home-based records (HBR) ownership in children 12–59 months, nationally by reported practice of checking vaccination status in 2018

Country reported implementing checking vaccination status at school in 2018	n (%) HBRs seen at the time of the survey median, range
	12–23 months n = 62	24–35 months n = 58	36–47 months n = 19	48–59 months n = 19
Yes	n = 38 (61%)81.0, 52.3–97.6	n = 35 (60%)77.0, 30.9–98.2	n = 9 (47%)71.0, 44.4–86.0	n = 9 (47%)66.6, 39.2–85.0
No	n = 24 (39%)73.2, 10.0–94.0	n = 23 (40%)62.6, 18.8–89.2	n = 10 (53%)52.6, 28.1–86.5	n = 10 (53%)43.25, 22.8–83.3

Sixty-two (62/145, 43%) respondents had data available for both net primary school enrollment and HBR ownership among children aged 12–23-months, largely from AFR 28/62 (45%), AMR 14/62 (23%), and SEAR 9/62 (15%). Twenty-four (24/62, 39%) had both high net primary school enrollment and high HBR ownership in children aged 12–23 months. Twenty-one of the 24 respondents also reported the practice of checking vaccination status at school (Fig. 6). The majority of these 21 respondents were HIC (9) and UMIC (9), and mostly in AMR (11) and EUR (6).

Fig. 6

Net primary school enrollment and home-based record (HBR) ownership for children aged 12–23 months with data available for both net primary school enrollment rate and HBR ownership among 38 respondents reporting checking vaccination status in school and 24 respondents reporting not checking vaccination status in school in 2018.

Monitoring and evaluation

Of 111 respondents to the question about whether the childcare or school keep a record (e.g., school health record or copy of HBR) of the child’s vaccination status, seventy-two (65%) reported this practice, including 30 HIC, 23 UMIC, 13 LMIC, and six LIC. The majority were in AMR (22/72, 31%), EUR (18/72, 25%), and AFR (15/72, 21%) regions. Twelve respondents reported that a copy of the child’s HBR is kept at childcare or school, five kept vaccination status as part of the school medical records, and three kept vaccination records in school immunization registers. Eight respondents stated that the type of record of a child’s vaccination status kept varied by school.

Of 115 respondents to the question about whether the results of checking vaccination status at school were routinely reported or monitored, over half (60/115, 52%) reported yes, while under half (54/115, 47%) did not routinely do so (one respondent did not know the answer to this question). The types of reporting and monitoring activities described predominantly focused on measuring vaccination coverage and the identification of school-age children requiring catch-up vaccination. One respondent shared that school vaccination surveys were implemented annually in kindergarten and middle schools, and quarterly for licensed childcare facilities. Four respondents discussed the use of an electronic immunization register to monitor immunization data about school-age children.

Of 117 respondents to the question about whether the strategy of checking vaccination status of children at school was ever evaluated, 38 (32%) reported yes, and consisted mainly of countries in the AMR (14/38, 37%) and EUR (12/38, 32%) regions. Reported evaluation activities mostly related to assessing vaccination coverage of school-age children. One respondent noted that the shift to an electronic immunization register provided the opportunity to check the vaccination status of school-age children, which was previously not felt to be as feasible.

Support needs

Thirty respondents (30/145, 21%) reported that they would like some level of support to develop or enhance the policy or practice of checking vaccination status at school, including seven from each region of AFR, AMR, and WPR. Specific types of support included the development of policy (10 respondents) or guidelines (five respondents), learning more about other countries’ experiences (10 respondents), and having global guidance on the topic (four respondents). Thirteen respondents (43%) requested support for monitoring and evaluation of checking vaccination status at school (four from WPR, three from AFR, and two each from AMR, EMR, and EUR). Respondents also noted that having a law (eight respondents) or policy (four respondents) about checking vaccination status in school, guidelines for implementation (four respondents), or an electronic immunization register (seven respondents) would help start or improve checking vaccination status at school. Fourteen respondents noted that specific evidence on the effect of this strategy, particularly on immunization coverage and VPD incidence would be useful, predominantly for advocacy with key decision-makers.

Discussion

Checking vaccination status at school is widely recommended as a way to improve routine childhood immunization coverage and has been implemented in some countries since the 1970s. Three-quarters (77%) of the JRF supplementary survey respondents reported that they implemented checking vaccination status at school, mostly at pre-primary and primary school. Implementation was most often accompanied by a law or policy, issued by either the Ministry of Health, the Ministry of Education, or both. What was checked, by whom and when, and how missed vaccine doses were delivered varied considerably across the countries. Very few survey respondents reported the monitoring or evaluation of existing practices of checking vaccination status at school. Twenty-five countries (17%) reported neither a policy nor practice of checking vaccination status at school, predominately LICs, with lower HBR and school enrollment than those that reported checking.

While global vaccination coverage increased substantially in the first decade of the 21st century, there have been only modest gains since 2010[26]. The disruption of routine immunization by the coronavirus disease 2019 (COVID-19) pandemic and widescale, rapid vaccination against COVID-19 have increased attention toward attaining health security, the need for public health systems, and the optimization of these systems, including those for immunization[27], [28], [29], [30], [31]. Checking vaccination status in schools has the potential to strengthen the immunization system and enhance vaccination coverage in several ways, as described during the global consultation on implementing vaccination checks at school, hosted by WHO in November 2019[9]. This strategy allows for the identification of zero-dose or incompletely vaccinated children, including those from difficult-to-reach populations who may not routinely access or utilize primary health care services. It also enhances the need for complete and accurate data in immunization information systems, promotes HBR ownership, and builds cooperation between health and education sectors. Checking vaccination status at school may also benefit the education system by reducing VPD outbreaks in the school community and creating a healthy environment to optimize learning.

Results from the JRF supplementary survey indicate that many responding countries were already leveraging existing health and education sectors to routinely check the vaccination status of the students in 2018. In countries where nominal electronic immunization registers exist, these were used as the predominant information source for checking children’s vaccination status at school, highlighting their importance. Once school-based vaccination checking was able to identify students as eligible for catch-up vaccination, missed vaccine doses were delivered mainly at primary health centers (via referral), some of which followed up to ensure vaccinations were received. The policy and practice of checking the vaccination status at school were disproportionately more prevalent in high- to upper-middle-income countries, where robust health and education systems, well-financed routine immunization programs, high school enrollment, and human resource availability and capacity may facilitate this strategy. Before starting to check vaccination status at school, countries should assess the capacity of their education and health systems for supporting the necessary activities, including the provision of missed doses of vaccine to eligible children. Whenever resources for both immunization and education are already limited, and cannot be obtained from global partners, careful consideration is needed to avoid possibly diverting resources from other vital public health and education initiatives.

HBRs are a key component of any health system and essential to facilitate the implementation of any strategy to check vaccination history—from the health center to the school and workplace. Checking vaccination status should be coupled with approaches to reduce barriers to accessing missed vaccine doses, such as offering missed vaccine doses at the time of screening or referral to a health facility with routine follow-up. This would have implications for response to outbreaks of VPDs in the school setting because heightened awareness of students’ vaccination status can help reduce exposure, particularly of unvaccinated children who are more at risk of contracting VPDs. Vaccination checks at the earliest possible level of the childcare or formal education system will decrease the window of susceptibility for zero dose or incompletely vaccinated children, while increasing population immunity (particularly for measles) in younger age cohorts who are often more susceptible to severe illness and death from VPDs. Once a school vaccination checking platform is functioning, additional public health interventions can be integrated if they can be accommodated by health and education systems.

The practice of checking children’s vaccination status at school was often reported to be accompanied by a policy requiring vaccination prior to school entry, which may be met with reticence in some settings. Data on the impact of mandating childhood vaccines for school entry is both limited and specific to high-income countries, including the United States of America, where state-based school immunization laws with complex processes of granting exemptions, have contributed to reduced incidence of VPDs and increased immunization coverage in school-age children[32], [33]. Examples from several countries demonstrate the possible negative effects of requiring vaccination to access education, such as appearing to restrict the child’s right to education or remove eligibility for essential welfare payments, which can disproportionately impact the most vulnerable populations[34]. Linking childhood vaccination to monetary incentives or access to education has the potential to stoke anti-vaccine sentiment, possibly affecting acceptance of other recommended vaccines throughout the life-course[35]. The decision to establish vaccine mandates should be preceded by careful planning to ensure an adequate and safe vaccine supply for all groups which the mandate covers as well as be part of a multi-pronged approach to improving vaccine uptake. If governments decide to proceed with mandates, certain approaches such as monitoring vaccine safety, compensation scheme for pre-determined rare adverse events and avoidance of vaccine-specific mandates should be considered[36]. An alternative approach to mandating vaccination for school entry is creating a system where vaccination status is checked and missed doses provided at the same time and location, and record of a child’s vaccination status is kept by the school. Such an approach as the potential to reduce barriers to access and utilization of immunization services, enhance education staff involvement in, and awareness of, vaccination, and allow for swift identification of unvaccinated children at school in the event of a VPD outbreak.

The JRF supplementary survey identified specific areas where further evidence and support are needed to introduce checking vaccination status at school or enhance existing approaches, along with specific challenges faced in this strategy. Survey respondents reported interest in support to develop policies or operational guidelines for checking vaccination status at school, conducting monitoring and evaluation to understand optimal implementation approaches, outcomes, and impact. Providing the necessary evidence to advocate for the introduction of checking vaccination status at school or to augment existing implementation should be done with the understanding that no one approach will be effective in all settings. However, common factors have been identified as essential in planning and implementing school vaccination checks and can be advocated by National Immunization Technical Advisory Groups or similar bodies. These factors include: strong collaboration between Ministries of Health and Education, along with other relevant ministries and organizations; laws and policies, particularly around catch-up vaccination, that are supportive rather than prohibitive; attention to the feasibility of such policy and practice, such as the level of school enrollment, the capacity of human resources, availability of HBR or other immunization records, and vaccine supply; clear guidance on roles and responsibilities for implementation; and engagement with stakeholders to understand the attitudes and knowledge towards vaccination and checking practices[9].

The JRF supplementary survey is subject to several limitations including that of the JRF methodology, such as self-report and the lack of validation, which have been previously described[37]. Focusing on results of a one-time survey allowed for an in-depth exploration of the policy and practice of checking vaccination status in schools. However, given that not all countries completed this supplementary survey, the true prevalence and extent of implementation of this practice globally remains unknown. The JRF supplementary survey response rate varied by WHO regions; thus, some WHO regions were less represented than others. Little is known about the policy and practice of checking vaccination status at school among non-respondents. As it has been suggested in survey methodology literature, they may systematically differ from respondents (non-response bias)[38]. Lack of sub-national level information about the policy and practice of checking vaccination status at school limits the contexts from which strengths and challenges of the approach can be drawn. Data on HBR ownership were missing for many countries because DHS and MICS are primarily performed in low- and lower-middle-income countries, leading to an under-representation of higher-income countries in these data. HBR data were most complete for children aged 12–23 months and less so for older age groups, limiting the ability to observe more than trends regarding HBR availability and checking vaccination status at school. Results from the population-based survey platforms, such as DHS and MICS have also documented lower rates of HBRs seen compared to vaccination coverage surveys commissioned by national expanded programs on immunization (EPI) when conducted in the same year, possibly indicating an under-representation of HBR ownership in the data that was used in these analyses[39].

While the JRF supplementary survey provides useful information on the prevalence of checking vaccination status at school, documentation of the approaches taken, what has worked or has been unsuccessful, and the effects of this strategy remains sparse, particularly in low- and middle-income countries. A broader array of experiences in planning, implementing, monitoring, and evaluating checking vaccination status at school should be documented and published, particularly those from sub-national areas. This will help to enhance the evidence base about the possible array of context-specific approaches, along with the lessons learned and effects observed. Monitoring and evaluation of this widely recommended strategy on VPDs should be included for both existing and new strategies to check vaccination status at school, particularly in low- and middle-income countries. Additionally, resources should be dedicated to using evidence to optimize implementation approaches, demonstrate effects, and disseminate findings amongst the global community. While work remains to be done in the introduction, implementation, monitoring, and evaluation of checking vaccination status at school, this strategy has the potential to help optimize population immunity to VPDs among school-aged children as part of a life-course approach to vaccination.

Disclaimer

The findings and conclusions in this manuscript are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. Some of the co-authors are staff members of the World Health Organization (WHO). The authors alone are responsible for the views expressed in this publication, and they do not necessarily represent the decisions, policy, or views of the WHO.

Funding

This work was not supported by funding from agencies in the public, commercial, or not-for-profit sectors.

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this manuscript.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.