Background: To address a high incidence of serogroup B invasive meningococcal disease (IMD-B) in the Saguenay-Lac-Saint-Jean region, Quebec, Canada, a mass vaccination campaign targeting nearly 60,000 individuals ≤20 years old was launched in May 2014. Because of the limited clinical experience with the four-component meningococcal B vaccine (4CMenB), active surveillance for adverse events following immunization (AEFI) was conducted. This paper reports 4CMenB AEFI surveillance findings.
Methods: Active surveillance assessed AEFIs with acute onset within 7-days post-immunization, AEFI-associated absenteeism and medical consultations, impact of antipyretic prophylaxis and coadministration of other vaccines.
Results: By July 17, 2015, 83% and 77% of the 59,098 individuals targeted by the campaign had received a first and a second dose of 4CMenB. The incidence of fever on days1-2 was highest in children <2 years old but only 0.6% reported a temperature ≥40◦C. Among children <10 years old, ≥2doses of acetaminophen prophylaxis significantly reduced fever incidence on days1-2 after dose1&2. Absenteeism or a medical consultation during the 7 days following vaccination was reported by 6.2% of vaccinees post-dose1 and 9.2% post-dose2 and was most often reported in association with fever/malaise (4.2%) or injection site reactions (3.6%).
Conclusion: Large-scale population-based surveillance identified a 7-day reactogenicity profile consistent with earlier clinical trials with the 4CMenB vaccine but indicating frequent AEFI-associated absenteeism and medical consultations affecting the societal cost of this vaccine. We conclude acceptable vaccine safety and risk-benefit profile overall on the short term, particularly as an intervention to address a high regional incidence of IMD-B.
Keywords: 4CMenB; Meningococcal vaccine; Reactogenicity; Vaccine safety.
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