Assessing vaccination coverage and antibody levels for measles, pertussis, and tetanus in Boende, DR Congo: Implications for maternal and child health.

INTRODUCTION

Despite vaccines' global success, vaccine-preventable diseases/infections remain a major cause of child mortality. The DRC, and particularly Tshuapa province, faces persistent challenges in improving coverage. Most vaccination coverage studies in the region rely on vaccination cards and caregiver recall, which can be prone to inaccuracies.

METHODS

We conducted a 30 × 7 cluster survey with a serology component in Boende Health Zone, Tshuapa. Tshuapa. Antibodies against measles, pertussis, and tetanus were measured using ELISA on dried blood spots from postpartum women and children aged 12-23 months. Two measles cut-offs (150 and 275 IU/L) were applied due to lack of standardization.

RESULTS

The study enrolled 205 children and 208 women. Among women, 73 % had tetanus antibody levels above the protective threshold, 0 % had antibodies against pertussis above the predetermined cut-off, and measles seropositivity was 55 % at the more stringent cut-off (275 IU/L) and 81 % at a more relaxed one (150 IU/L). In children, 18 % had tetanus antibodies above the protective threshold and 5 % had antibodies above the pertussis cut-off point. and 18 % and 30 % for measles (strict and relaxed, respectively). In five clusters, no children had antibodies above the cut-off points for any of the three pathogens.

CONCLUSION

These findings highlight the potential need to include pertussis vaccination in the national maternal immunization program and advocate for integrating serology into vaccination coverage surveys to provide more accurate assessments. The disparity between reported vaccination rates and serological data could be due to one or a combination of recall bias, desirability bias, test variability, antibody waning, and possible concerns about vaccine potency and record accuracy in remote areas in the Boende Health Zone. This stresses the urgent need to improve vaccination coverage and surveillance efforts in Boende Health Zone and the broader Tshuapa province.