A model that works: Leveraging community health care workers (CHWs) to reach zero-dose and under-vaccinated children through the care group model approach; assessing continuity after initial contact

Emanuel Mwendo; Sia Marandu; Lilian Babyebonela; Bahati Sambayuka; Johnson Kisanga; Leah Mtui; Danford Barnaba; Linda Chatilla; Joseline Ishengoma; Elizabeth Nyema; Florian Tinuga; Georgina Joachim; Esther Mtumbuka

doi:10.15406/mojph.2025.14.00506

MOJ

eISSN: 2379-6383

Public Health

Research Article Volume 14 Issue 3

A model that works: Leveraging community health care workers (CHWs) to reach zero-dose and under-vaccinated children through the care group model approach; assessing continuity after initial contact

Emanuel Mwendo, Sia Marandu, Lilian Babyebonela, Bahati Sambayuka, Johnson Kisanga, Leah Mtui, Danford Barnaba, Linda Chatilla, Joseline Ishengoma, Elizabeth Nyema, Florian Tinuga, Georgina Joachim, Esther Mtumbuka

Received: December 02, 2025 | Published: December 16, 2025

Citation: Mwendo E, Marandu S, Babyebonela L, et al. A model that works: Leveraging community health care workers (CHWs) to reach zero-dose and under- vaccinated children through the care group model approach; assessing continuity after initial contact. MOJ Public Health. 2025;14(3):294-299. DOI: 10.15406/mojph.2025.14.00506

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Abstract

Background: Tanzania has made notable progress in expanding immunization coverage; however, a considerable number of children remain zero-dose or under-vaccinated. Operationally, Gavi defines zero-dose children as infants who have not received the first dose of a diphtheria, tetanus, and pertussis–containing vaccine (DTP1) by the end of their first year of life, while under-vaccinated children are those who have not received the third dose of a DTP-containing vaccine (DTP3) within the same period (Gavi, 2021–2025 Equity Goal). To address these persistent gaps, the Care Group Model (CGM) was implemented in the Mbeya Region in 2024 and 2025, leveraging community health workers to conduct household visits, identify missed children, and link them to immunization services. Methods: Ten health facilities were purposively selected based on having the highest number of zero-dose children and those who had received DTP1 but had not returned for DTP2. A retrospective review of CGM registers and facility immunization registers was conducted to determine whether children identified and vaccinated during CGM follow-up returned for subsequent doses. Data was analyzed using STATA version 16, calculating proportions and odds ratios to assess continuity of care and the likelihood of returning for the next scheduled dose. Results: In Mbeya DC, 96.9% (31/32) of zero-dose children and 91.4% (53/58) of those missing the second Pentavalent dose completed subsequent vaccinations. In Mbarali DC, 89.7% (52/58) of zero-dose children and 95.6% (109/114) of those missing the second Pentavalent dose completed subsequent doses. Across districts, continuity of care exceeded 90%. Children were reached through both fixed-site and outreach services, demonstrating operational flexibility and equitable access. Conclusion: The CGM demonstrated strong effectiveness in ensuring continuity of care for zero-dose and under-vaccinated children. Its success likely stemmed from communitybased identification, trusted engagement by Community Health Care Workers (CHWs), and integration with facility and outreach services. Expansion of this approach could accelerate progress toward universal immunization coverage in Tanzania and similar settings.

Keywords: immunization coverage, zero-dose children, under-immunized children, community health workers, continuity of care, Tanzania