Meningitis B Vaccine Shows Disappointing Immune Response

The protection and immunity rate for serogroup B meningococcal vaccine Bexsero (4CMenB) may be lower than expected, recent research results suggest.

The study, which was published in the July 2016 issue ofNew England Journal of Medicine,investigated the 2013 meningitis B (MenB) outbreak at Princeton University and found that 34% of students vaccinated with 2 doses of Bexsero didn’t develop antibodies and therefore weren’t immune to MenB.

Although rates of meningococcal disease in the United States have been declining since the late 1990s, college students are among those at greatest risk because of their close living conditions and potentially risky behaviors.

From March 2013 to March 2014, the Princeton campus experienced 9 cases of MenB, including one that became fatal. With special FDA approval, all 6000 Princeton students were eligible to receive the Bexsero vaccine to protect them from the outbreak. Of those students, 89% received at least the first dose within 2 months.

Researchers collected blood samples from 499 students who had received both doses. Of that cohort, just 66% showed bactericidal activity against the strain of MenB that infected students on campus—although none of those students actually contracted MenB.

“This level of seropositivity was lower than expected, given the antigenic similarity between the outbreak strain and the components of the vaccine and given that the Meningococcal Antigen Typing System predicted that 4CMenB would induce responses against the outbreak strain,” the authors wrote.

At the time, Bexsero was only approved for use in Canada and Europe. TheFDA approved the productfor use in the United States in January 2015.

Prior to this special approval, the only other MenB vaccine approved by the FDA was a 3-dose vaccine called Trumenba. All other meningitis vaccines licensed in the United States protect against more common strains of meningococcus: groups A, C, W, and Y.

“We had the unique opportunity to test the vaccine before licensure in US,” said Nicole Basta, PhD, MPhil, assistant professor of epidemiology and community health at the University of Minnesota. “All students who were tested had an immune response to at least one strain contained in the vaccine, but one-third didn't have any response to the outbreak strain.”

For now, the CDC’s Advisory Committee on Immunization Practices recommendations state that a MenB vaccine may be administered to adolescents and young adults 16 to 23 years to provide short-term protection against most strains of serogroup B meningococcal disease.

“For a relatively uncommon but devastating infectious disease, the regulatory approval of a vaccine in the absence of ideal data may be necessary and appropriate if the vaccine is deployed in the context of a systematic public health response,” wrote Jerome Kim, MD, in an accompanying editorial.

Even with those small numbers, Dr. Basta said she’d recommend Bexsero to teens and young adults, especially those heading to college. Many states require incoming college students to have a meningitis vaccination prior to arriving on campus, and retail clinicians should promote their clinic as a convenient place to receive needed immunizations.