Evaluation report
Reducing zero-dose children and improving routine immunization following COVID-19 through community health workers in Cameroon.
Martha Ndiko Ngoe, Pamela Besong Oben, Daniel Nebongo Nebongo, Perpetua Bihnwi Tayoh Yelluma, Wilson Fosack Nsanda et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001A study in Cameroon evaluated training community health workers (CHWs) and health care workers (HCWs) to find unvaccinated children and link them to immunization services after COVID-19 disrupted vaccination programs. Over five months, the intervention in two health districts increased doses administered substantially, with Penta-1 doses rising from 285 to 3,172 and Penta-3 doses from 321 to 2,893. The program cost USD 7,240 and reached 299 zero-dose children through 945 home visits. The approach worked well in a conflict-affected setting with displaced populations where traditional coverage measures were difficult to track.
Key points
- Penta-1 doses increased from 285 pre-intervention to 3,172 post-intervention
- Penta-3 doses increased from 321 to 2,893
- HPV vaccination reached 2,134 adolescents (1,747 girls; 387 boys)
- CHWs identified 299 zero-dose children through 945 household visits
- Operational cost was USD 7,240 with estimated vaccine value of USD 31,101
Limitations
The study measured doses administered rather than vaccination coverage due to mobile IDP populations, making it unclear whether improvements represent truly increased coverage or temporary increases in activity. External factors such as conflict intensity and sporadic outreach activities were not consistently documented, so their contribution to outcomes cannot be ruled out.
Abstract
Routine immunization in Cameroon was severely disrupted by the COVID-19 pandemic, compounding longstanding challenges stemming from sociopolitical instability in the South-West Region. Kumba, hosting large populations of internally displaced persons (IDPs), reported increasing numbers of zero-dose and under-immunized children. This study assessed the effect of training Community Health Workers (CHWs) and Health Care Workers (HCWs) to identify, refer, and link zero-dose and under-vaccinated children to services in Kumba North and South Health Districts. Six low-performing health areas were selected based on routine immunization data. From October 2022 to February 2023, CHWs conducted household visits, identified unvaccinated children, and provided referrals, while HCWs received training on reducing missed opportunities for vaccination (MOV). Monthly supervision and data review supported implementation. Due to large, mobile IDP populations, outcome measures focused on doses administered, not coverage. Costs were estimated using operational expenditures and UNICEF vaccine procurement prices. Penta-1 doses increased from 285 pre-intervention to 3,172, while Penta-3 doses increased from 321 to 2,893. HPV vaccination reached 2,134 adolescents (1,747 girls; 387 boys). CHWs conducted 945 home visits and identified 299 zero-dose children. Operational cost was USD 7,240, and the estimated value of vaccines administered was USD 31,101. Although external factors such as fluctuating conflict intensity or sporadic outreach may have contributed, these were not consistently implemented in the intervention areas. CHW engagement combined with HCW MOV-reduction training substantially increased doses administered in a conflict-affected setting. This low-cost, scalable model can strengthen routine immunization and reduce zero-dose inequities in humanitarian contexts.
Findings the Hub has extracted
Each claim below is labelled by its type of design and links back to this report.
- Intervention
- Training community health workers to identify, refer, and link zero-dose and under-vaccinated children to immunization services, combined with training health care workers to reduce missed vaccination opportunities
- Population
- Children in six low-performing health areas in Kumba North and South Health Districts, Cameroon, including internally displaced persons
Key finding
Penta-1 doses increased from 285 to 3,172 (11-fold increase)