Incidence and types of adverse events during mass vaccination campaign with the meningococcal a conjugate vaccine (MENAFRIVAC™) in Cameroon.

PURPOSE

A new vaccine against meningitis A was introduced in Africa meningitis belt in 2010. This study was planned to describe the incidence and types of adverse events following immunization (AEFIs) with a new conjugate vaccine against meningitis A (MenAfrivac™) in a Cameroonian vaccination campaign.

METHODS

The campaign was conducted in Adamawa and North West regions in December 2012 and the AEFIs enhanced surveillance from December 2012 to January 2013. Incidence rates (IR) of overall and serious AEFIs were estimated as well as AEFI incidence rates by type, age group and region. AEFI symptoms were aggregated in System Organ Class (SOC).

RESULTS

Of 2 093 381 persons vaccinated, 1352 AEFIs were reported. Of these, 228 (16.9%) were excluded because of not meeting inclusion criteria and 1124 (83.1%) included (IR: 53.7/100 000 doses administered/8 weeks). Of the 82 serious AEFIs reported, 52 (63.2%) met the case definition. 23 (28.1%) were investigated, of which 4 (17.4%) were probably vaccine product-related reactions (IR: 0.2/100 000 doses administered/8 weeks). Fever was the most common reported AEFI with 626 cases (IR: 31.4/100 000 doses administered/8 weeks). The proportion of people with the SOC "Gastrointestinal disorders" was significantly lower in ages 5-15 and 16-29 years than 1-4 years [aRR = 0.63(0.42-0.93) and 0.54(0.36-0.81) respectively].

CONCLUSION

Incidence and types of AEFI reported during MenAfriVac vaccination campaign organized in Cameroon in 2012 did not suggest concern regarding the vaccine safety. Differences in frequency of AEFIs types per age group could guide the monitoring of AEFIs frequency in future campaigns. Efforts are needed to improve the investigation rate of serious AEFIs. Copyright © 2016 John Wiley & Sons, Ltd.