The vaccine even provided significant protection when children had just one dose, investigators found.
A new report out of Spain suggests the four-component, protein-based meningococcal serogroup B vaccine (4CMenB; Bexsero) meaningfully reduces the risk of invasive serogroup B and non–serogroup B meningococcal disease in children under the age of 5.
The report, published in the New England Journal of Medicine, is notable because it provides some of the first real-world post-commercialization effectiveness data on the vaccine, according to the authors.
Corresponding author Jesús Castilla, MD, PhD, of the Public Health Institute of Navarra, Spain, and colleagues, explained that the introduction of serogroup C vaccines greatly reduced the risk of invasive meningococcal disease in Europe, but that left serogroup B meningococcal disease as a significant risk.
The 4CMenB vaccine has been approved in Europe since 2013, and has been included in Spain’s publicly funded vaccination schedule since 2015 for high-risk individuals. The Spanish Pediatrics Association recommends the vaccine for all children 2 months of age and older, and Castilla and colleagues said that has led to a steady increase in vaccination rates.
Still, the authors said it has been difficult to generate meaningful evidence of the vaccine’s performance in real-world settings.
“Although some countries have introduced 4CMenB into publicly funded infant immunization programs, the low incidence of the disease has limited the conduct of postcommercialization studies of effectiveness,” they noted. “The few published evaluations have yielded effectiveness estimates from 59.1% (with a two-dose priming schedule plus a 1-year booster in the United Kingdom) to 93.6% (with a four-dose schedule in Tuscany, Italy).”
They added that there is also evidence that the vaccine may provide protection against diseases caused by other serogroups.
In hopes of better understanding the vaccine’s impact in Spain, the investigators designed a nationwide matched case-control study examining all cases of invasive meningococcal disease in children under the age of 5 between October 2015 and October 2019. They then matched each case with 4 age- and location-matched controls.
A total of 306 cases of meningococcal disease were included in the analysis. Most of those (243 cases; 79.4%) were serogroup B cases. A total of 1,224 controls are also analyzed.
Of the cases, just 35 patients (11.4%) had been vaccinated with at least one dose of 4CMenB. The vaccination rate was higher in the control group (24.3%).
The results of the analysis support the use of the vaccine, Castilla and colleagues said.
“We found that complete vaccination with 4CMenB was 76% effective in preventing meningococcal disease caused by any serogroup, 71% effective in preventing disease caused by serogroup B, and 92% effective in preventing disease caused by non–serogroup B meningococci,” the investigators reported.
They found the vaccine was still 54% effective even if patients had only had one dose of the vaccine, instead of the full 2-dose course. In addition, they said none of the people affected by strains protected by the vaccine had been vaccinated, suggesting that the vaccine worked as expected.
In their conclusion, the authors conceded that their sample size was small for the type of analysis conducted and that it is possible the socioeconomic and geographic factors acted as confounding factors in the results.
However, they said these data are an encouraging sign of the benefits of vaccination.
“This evidence may be useful in making decisions about the inclusion of this vaccine in the immunization program of countries where invasive meningococcal disease in children is problematic and its prevention a priority,” they said.