Long-term protection against invasive meningococcal B disease and gonococcal infection five years after implementation of funded childhood and adolescent 4CMenB vaccination program in South Australia: an observational cohort and case-control study
Bing Wang, Lynne Giles, Prabha Andraweera, Mark McMillan, Rebecca Beazley, Sara Almond GradCert, Noel Lally, Charlotte Bell, Louise Flood, James Ward, Helen MarshallAbstract
Background
A publicly funded 4CMenB program has been implemented in South Australia since 2018. We aimed to evaluate vaccine effectiveness (VE) and vaccine impact (VI) on invasive meningococcal B (MenB) disease and gonococcal infections five years after the program introduction.
Methods
VI was assessed using a Poisson or negative binomial regression model, and VE was estimated using both cohort screening and case-control methods. VE against the subsequent gonococcal infection was measured using a Cox regression model.
Results
Relative reductions of 72.7% (95%CI 38.0% to 88.0%) and 76.2% (95%CI 41.6% to 90.3%) in the incidence of MenB disease were observed in infants aged <one year and adolescents aged 15-18 years, respectively. The VE against MenB disease for the three-dose schedule was 98.5% (95%CI 81.9% to 99.9% in children and 92.3% (95%CI 34.3% to 99.1%) for the two-dose vaccination in adolescents. Two-dose VE against gonococcal infections in adolescents was 39.1% (95%CI 31.3% to 46.0%). Lower VE estimates were demonstrated in those >5 years compared to within 5 years since vaccination (-6.3% (95%CI -44.5% to 21.8%) vs 41.8% (95%CI 34.0% to 48.7%). The VE against the subsequent gonococcal infection was 27.0% (aHR=0.730; 95%CI 0.540 to 0.988), comparing fully vaccinated cases with unvaccinated cases.
Conclusions
4CMenB demonstrates high protection against MenB disease in children and adolescents at 5 years. Moderate protection against the first and subsequent gonococcal infections in adolescents was observed up to 5 years post vaccination with waning evident after 5 years.