Study confirms group B meningitis vaccine efficacy

Group B meningitis poses a serious health risk to children, but the disease is vaccine preventable. A recent study published in the New England Journal of Medicine evaluated the efficacy of vaccination with the multicomponent meningococcal group B (4CMenB) vaccine for actual versus expected incidence of the disease in young children with positive results.¹

The 4CMenB vaccine became a part of the publicly funded immunization program in the United Kingdom in September 2015. It was given in a 2-dose priming schedule in infants along with a 12-month booster. The researchers compared the observed incidence of meningococcal group B disease with the expected incidence, which was based on the incidence during the 4-year prevaccination period in equivalent cohorts. They also used disease trends from cohorts of children aged younger than 5 years who were ineligible to get the vaccine.

During the study period, the number of children receiving the 4CMenB vaccine remained high, with data in the first 3 months of 2018 showing that 92.5% of children had received the primary immunizations by their first birthday and 87.9% of children had completed the 3-dose series by their second birthday.

4CMenB proved effective in reducing cases of group B meningitis

From the start of 4CMenB’s inclusion in the program in September 2015 to August 2018, the incidence of meningococcal disease was significantly lower in the vaccine-eligible cohorts than the expected incidence (63 observed cases compared with 253 expected cases; incidence rate ratio, 0.25; 95% confidence interval [CI], 0.19-0.36). Additionally, there was a 75% reduction of incidence of meningococcal disease in the age groups that were considered fully eligible to receive the vaccine.

In the 2-dose priming schedule for infants, the adjusted vaccine effectiveness was 52.7% (95% CI, −33.5 to 83.2. The effectiveness rose with the 2-dose priming schedule plus a booster at age 1 year to 59.1% (95% CI, −31.1 to 87.2). Over the course of the 3 years studied, a total of 169 cases of meningococcal group B disease occurred in the vaccine-eligible cohorts and an estimated 277 cases (95% CI, 236-323) were prevented.

The researchers concluded that the 4CMenB vaccine had a positive effect against meningococcal group B disease and that protection from the disease lasted at least 2 years after receiving 3 doses. Interestingly, in the same issue of the New England Journal of Medicine, there was an Australian study that examined whether the 4CMenB vaccine can build herd immunity in teenagers.² The results indicated that the vaccine does not, making it even more imperative that children receive the vaccine when they are young.

References:

1. Ladhani SN, Andrews N, Parikh SR, et al. Vaccination of infants with meningococcal group B vaccine (4CMenB) in England. N Engl J Med. 2020;382(4):309-317.

2. Marshall HS, McMillan M, Koehler AP, et al. Meningococcal B vaccine and meningococcal carriage in adolescents in Australia. N Engl J Med. 2020;382(4):318-327.