Abstract
Background
4CMenB is a protein-based meningococcal B vaccine, but the vaccine antigens may be present on non–group B meningococci. In September 2015, the UK implemented 4CMenB into the national infant immunization program, alongside an emergency adolescent meningococcal ACWY (MenACWY) program to control a national outbreak of group W (MenW) disease caused by a hypervirulent strain belonging to the ST-11 clonal complex. The adolescent program aimed to provide direct protection for adolescents and indirect protection across the population.
Methods
Public Health England conducts meningococcal disease surveillance in England. MenW cases confirmed during 4 years before and 4 years after implementation of both vaccines were analyzed. Poisson models were constructed to estimate direct protection against MenW disease offered by the infant 4CMenB program along with the indirect impact of the adolescent MenACWY program in children eligible for 4CMenB but not MenACWY.
Results
Model estimates showed 69% (adjusted incidence rate ratio [aIRR], .31; 95% CI, .20–.67) and 52% (aIRR, .48; 95% CI, .28–.81) fewer MenW cases than predicted among age-cohorts that were fully- and partly-eligible for 4CMenB, respectively. There were 138 MenW cases in <5-year-olds. 4CMenB directly prevented 98 (95% CI, 34–201) cases, while the MenACWY program indirectly prevented an additional 114 (conservative) to 899 (extreme) cases over 4 years. Disease severity was similar in 4CMenB-immunized and unimmunized children.
Conclusions
This is the first real-world evidence of direct protection afforded by 4CMenB against MenW:cc11 disease. 4CMenB has the potential to provide some protection against all meningococcal serogroups.
Intussusception incidence among infants in the UK and Republic of Ireland: A pre-rotavirus vaccine prospective surveillance study