Introduction: the establishment of effective community-based surveillance is an essential objective of all disease surveillance systems. Several studies and reports have found that the situation is far from optimal in several developing countries such as Cameroon.

Methods: we conducted a cross-sectional descriptive study to assess the contribution of community health workers to surveillance of vaccine-preventable diseases in Obala health district. The performance of community health workers was measured using: the number of cases referred to the health center, the percentage of accomplished referrals, the percentage of cases referred by community health workers confirmed by the staff of health centers. A questionnaire containing forty-seven questions (open-ended and closed-ended) was used for interviews with community health workers. The data were analyzed using SPSS 21 and Excel 2007. Counts and percentages are reported.

Results: the study showed that the age ranged of community health workers was from 24 to 61 years with an average of 37.9 years ± 6.7 years. The most represented age group was between 40 and 50 with a percentage of 38.6%. The male sex was more represented than the female sex (61.4% vs 38.6%) or a sex ratio male man of 1.7. Forty-five percent of community health workers were selected at a village meeting, 93.1% of community health workers were involved in the surveillance of vaccine-preventable diseases and 87% experienced at least one preventable disease. Only 45.8% of them had the case definitions of the four diseases. Analysis of community health workers attendance at organized health committee meetings showed that 79% of community health workers attended at least one health committee meeting in 2015 and only 49% were monitored in 2015. Community health workers reported 42 suspected cases of measles, 37 of which actually went to the nearest Health Center, a baseline rate of 88%.

Conclusion: community health workers play a key role in the control of vaccine-preventable diseases in the Obala health district. Community-based surveillance is the foundation of surveillance activities. It is a mechanism based on simple case definitions of priority diseases and unexpected events or unusual conditions. Our study also reaffirms the importance of mastering case definitions and home visits and early detection of vaccine-preventable diseases.