Identifying the Zero-dose and Under-immunized Children in Bangladesh: Approaches and Experiences

"There was some social stigma in regard to vaccination, when a child get fever after taking the vaccine, the person then spread this message to other people surrounding them telling that the child got sick from receiving vaccination. This discourages other women..."

In Bangladesh, where the Expanded Programme on Immunization (EPI) resulted in an increase in full vaccination coverage from less than 2% in 1985 to 83.9% in 2019, communities remain where as many as 15% of children are un- or under-vaccinated. Gavi, under its Gavi 5.0 strategy and the global Immunization Agenda 2030, has focused on immunisation equity or reaching zero-dose (ZD) children (those who did not receive the first dose of diphtheria-tetanus-pertussis containing vaccine, or DTP1) and under-immunised (UI) children (those who did not receive the third dose of DTP-containing vaccine, or DTP3). This paper presents methods used to identify ZD and UI children in Bangladesh. It also describes demand- and supply side-barriers that lead to children being ZD and UI in the country.

As outlined here, Gavi set up Country Learning Hubs (CLHs) in Bangladesh, Mali, Nigeria, and Uganda, with the aim of using evidence to understand the factors influencing implementation and performance of approaches to identify and reach ZD and UI children. The Bangladesh CLH is tasked with developing the evidence base for tools and approaches that can be used to reach these children and their communities. This paper describes the results of the preliminary activities of the Bangladesh CLH as part of a rapid assessment.

Between December 2022 and May 2023, researchers from icddr,b collected and analysed both primary and secondary data to identify potential missed communities and barriers to immunisation. They identified missed communities using a 3-step process: (i) identification of high prevalence of ZD upazilas (i.e., sub-districts), (ii) identification of potential pockets of ZD within the selected upazilas, and (iii) a lot quality assurance sampling (LQAS) survey of caregivers of children aged 4.5-23 months to confirm whether or not the pockets were high prevalence. They conducted qualitative mapping to describe the characteristics of the missed communities, quantitative analysis of secondary data to identify factors related to ZD and UI, and interviews with service providers and mothers of children to identify barriers to immunisation. 

The data analysis confirms existence of ZD and UI children in areas that were categorised into haor (wetlands), hilly, char (sandy/silty land surrounded by water), coastal, plain land, and urban slums. Based on the LQAS survey, prime reasons for not having one's child vaccinated included the child being sick, vaccination not being permitted by the husband, financial limitations, and busy schedule of parents. When asked about their ability to identify and reach ZD or UI children, most upazila-level managers, service providers, and supervisors mentioned they had experienced difficulties in finding or monitoring ZD and UI children.

The respondents in qualitative interviews reported both demand and supply side factors that lead to ZD and UI. The prime demand-side factors were:
 

• Migration due to environmental damage or cultural reasons - For example, high rates of migration in slum settlements make it difficult to vaccinate, and, because many mothers work as labourers, it is difficult for them to reach clinics during operating hours.
• Fear of minor side effects - A few mothers and service providers mentioned that misconceptions about contraindications or concerns about side effects of vaccination sometimes hinder immunisation uptake. The crying that results after vaccination led some older family members to discourage women from bringing their children to the clinic.
• Misconceptions and hesitancy - Some religious leaders have actively spread misconceptions and even prevented EPI staff from disseminating messages using a loudspeaker. At the same time, some participants felt that EPI providers from outside the local ethnic community were not trusted. Participants said that the misconceptions kept some families from vaccinating their children.

The supply-side factors that participants noted include:
 

• Shortage of human resources (HR) and work overload - Perhaps the most important challenge was the large and severe limitations in HR for health, especially the shortage of health assistants (HAs) at field level.
• Limited opportunity to provide interpersonal communication (IPC) - Across the study sites, supervisors, providers and mothers discussed limited use of IPC to inform communities in advance of outreach services. Providers noted difficulties in visiting remote sites two days in a row, while some facilities managers said that even though HAs are recruited locally, they generally stay outside the area, making it difficult for them to visit the sites the day before a vaccination session.
• Distance to EPI centres and unavailability of transport - In hard-to-reach (HTR) areas, interviewees mentioned that households are scattered, and EPI clinics are located far from the community's centre (e.g., upazila headquarters). In urban areas, children may live close to an EPI clinic, but the number of children is large and not clearly defined, which creates challenges for the limited workforce. 
• Inaccurate denominator in EPI - Almost all the national-, district-, and upazila-level participants said they use a bottom-up approach to determining the estimated number of children eligible for vaccination (i.e., the denominator) for their micro plans, although participants described different calculations. This process was more difficult in areas affected by migration. 
   

The results of the determinant analysis suggest that, while wealth does not exert much influence over a child being ZD or UI, the mother's educational status, access to media, and practice or ability to make antenatal care visits were most strongly associated with children's vaccination status. The greater the status that a mother had in regards to these factors, the less likely was it for her child to be ZD or UI. Mothers who reported that their last child was unwanted were more likely to have a ZD child.

The researchers assert that the findings demonstrate the utility of combining existing survey and administrative data for identifying missed communities, but they also highlight the importance of field validation to confirm the results. Notably, they argue that the methods and approaches used in this study are both effective and easily replicable to identify ZD and UI children. The drivers of ZD and UI, along with the barriers to immunisation provide potential areas for intervention by policymakers and can highlight potential interventions to be tested in future implementation research.

Full list of authors, with institutional affiliations: Zerin Jannat, icddr,b; Hemel Das, icddr,b; Md. Wazed Ali, icddr,b; Nurul Alam, icddr,b; Mahbub E. Elahi Khan Chowdhury, icddr,b; Bidhan Krishna Sarker, icddr,b; Md. Mahbubur Rahman, icddr,b; Shehrin Shaila Mahmood, icddr,b; Md. Musfikur Rahman, icddr,b; Christopher Morgan, Jhpiego, The Johns Hopkins Affiliate; Elizabeth Oliveras, Jhpiego, The Johns Hopkins Affiliate; Gustavo Caetano Correa, Gavi, The Vaccine Alliance; Heidi W. Reynolds, Gavi, The Vaccine Alliance Tasnuva Wahed, icddr,b; Md. Jasim Uddin, icddr,b