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Complete vaccination with the four-component, protein-based meningococcal serogroup B vaccine (4CMenB; Bexsero) was found to be effective in the prevention of invasive serogroup B and non-serogroup B disease among children younger than 5 years, a matched case-control study from Spain showed.

In a group of 306 case patients and 1,224 matched controls, effectiveness of complete vaccination (meaning at least two doses of 4CMenB) reached 76% (95% CI 57-87) against invasive meningococcal disease caused by any serogroup, reported Jesus Castilla, MD, PhD, of the Instituto de Salud Pública de Navarra in Pamplona, and colleagues.

For kids who received one dose of the vaccine (11.4% of the case patients and 24.3% of the controls), effectiveness was 54% (95% CI 18-74), they noted in the .

Breaking it down by serogroup, complete vaccination was 71% effective against meningococcal serogroup B disease and partial vaccination was 50% effective, while these rates were 92% and 58%, respectively, for non-serogroup B disease.

"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," Castilla and team wrote.

They noted that post-hoc analyses showed no differences in effectiveness among fully vaccinated children according to number of vaccine doses (two or more than two) or the time elapsed since receipt of the last dose (<12 months vs ≥12 months).

Of note, complete vaccination was 71% effective (95% CI 43-86) against severe disease.

"In the analysis of the most severe cases, the estimates of effectiveness were similar to those in the main analysis, findings that are particularly relevant given that prevention of severe disease is the primary objective of vaccination programs," the authors wrote.

Previous studies looking at 4CMenB for and on indicated that effectiveness against invasive disease caused by meningococcal serogroups other than B "has been suggested and can be explained by the fact that the vaccine components are not unique to serogroup B," Castilla's group noted.

The 4CMenB vaccine contains four recombinant antigens, as well as outer-membrane vesicles containing Porin A subtype P1.4 from the strain NZ98/254, consisting of about a dozen serogroups including A, B, C, W, X, and Y. Of these, serogroups B, C, and Y are the most common in Europe and North America.

Meningococcal disease is rare and has a mortality rate of 10% to 15% in the U.S. It is spread by respiratory and throat secretions during close or lengthy contact, and is in children younger than 1 year, adolescents/young adults ages 16-23, and adults older than 85.

The CDC recommends vaccination in the U.S. The agency is also currently for an outbreak primarily affecting gay and bisexual men. In is part of national routine vaccinations in several countries, including Ireland, Italy, and the U.K., and has been part of the publicly funded immunization schedule for all children in Spain since 2000.

For this study, Castilla and team included 306 patients younger than 5 years (53.3% boys) who had a laboratory-confirmed PCR test for Neisseria meningitidis from October 2015 to October 2019, 5.2% of whom were fully vaccinated. Of these kids, 79.4% had serogroup B disease, 33.3% had a clinical presentation of meningitis, 38.6% had sepsis, and 24.8% had both meningitis and sepsis.

Each case patient was matched with four controls according to date of birth and province, for a total of 1,224 matched controls (50.7% boys), 14.2% of whom were fully vaccinated.

Because 4CMenB is available for private purchase in Spain, higher socioeconomic status might have been associated with higher vaccine coverage, Castilla and team said, and higher socioeconomic status is linked to a lower incidence of meningococcal diseases.

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