The outcomes of a randomized managed trial (RCT) point out that meningococcal B vaccine isn’t efficient at stopping gonorrhea an infection in high-risk teams.
The outcomes, offered this week on the Convention on Retroviruses and Infections by a staff of Australian researchers, present that amongst homosexual and bisexual males with a historical past of gonorrhea an infection who acquired both the 4CMenB vaccine or placebo, gonorrhea incidence was primarily the identical—roughly 48% in each arms.
The 4CMenB vaccine is designed to guard in opposition to 4 serogroups of Neisseria meningitidis, which may trigger invasive meningococcal illness. However lately, observational research have advised 4CMenB may additionally present average cross-protection in opposition to Neisseria gonorrhoeae, the bacterium that causes gonorrhea—one of the crucial frequent sexually transmitted infections (STIs) worldwide.
With greater than 82 million new gonorrhea infections recorded globally, incidence rising, remedy changing into extra sophisticated due to drug-resistant strains, and no current gonorrhea vaccine out there, public well being officers in some international locations have eyed meningococcal B vaccines as a possible technique to fight gonorrhea.
In Might 2025, amid a surge of gonorrhea infections in the UK, England’s Nationwide Well being Providers introduced that homosexual and bisexual males with a latest historical past of STIs or a number of sexual companions—a bunch at excessive danger for gonorrhea an infection—can be eligible to obtain 4CMenB at sexual well being clinics.
However the trial’s lead investigators say their outcomes, together with these from a smaller trial, point out the necessity to take a look at different choices.
“Taken collectively, these two research present sturdy proof that the 4CMenB meningococcal vaccine isn’t efficient at stopping gonorrhoea in homosexual and bisexual males who’re at excessive danger of contracting it,” lead investigator Kate Seib, PhD, of Griffith College, stated within the press launch.
‘Extremely disappointing’ outcomes
Co-lead investigator Andrew Grulich, PhD, MBBS, of the Kirby Institute known as the outcomes “extremely disappointing,” given the hopes that an efficient vaccine might remodel efforts to stop gonorrhea.
“We would like males who’ve acquired the 4CMenB vaccine within the hope of gonorrhoea prevention to know that the vaccine could be very secure and they’re going to have safety in opposition to some meningococcal strains,” Grulich stated. “Nonetheless, these males might want to discover different choices for prevention of acquisition of gonorrhoea, resembling condoms and common testing.”
Within the double-blind, placebo-controlled GoGoVax trial, 587 homosexual and bisexual males with a documented gonorrhea or syphilis an infection within the earlier 18 months have been randomly assigned 1:1 to obtain two doses three months aside for both 4CMenB or placebo from July 2021 by way of Might 2023. The first end result was the incidence of a gonorrhea an infection no less than 4 weeks after the second scheduled dose.
We would like males who’ve acquired the 4CMenB vaccine within the hope of gonorrhoea prevention to know that the vaccine could be very secure and they’re going to have safety in opposition to some meningococcal strains….Nonetheless, these males might want to discover different choices for prevention of acquisition of gonorrhoea, resembling condoms and common testing.
The incidence of a primary episode of gonorrhea was 48.1 per 100 person-years (160 infections amongst 296 contributors) within the 4CMenB group and 47.8 per 100 person-years (155 amongst 291 contributors) within the placebo group. The general vaccine efficacy was –0.5%.
The investigators word that the excessive charges of earlier gonorrhea an infection within the trial contributors might make them much less inclined to any potential protecting results from the 4CMenB vaccine. The research outcomes, nevertheless, can’t be generalized to different populations.
Limits of observational research
Among the many earlier research that advised 4CMenB might have a cross-protective impact in opposition to gonorrhea was a US Facilities for Illness Management and Prevention-led surveillance research carried out amongst 16- to-23-year-olds in Philadelphia and New York Metropolis from 2016 by way of 2018. That research discovered that receipt of two doses of the vaccine was related to a 40% diminished incidence of gonorrhea, in contrast with no vaccination.
“These findings counsel that MenB-4C might provide cross-protection in opposition to N gonorrhoeae and supply additional proof supporting feasibility of an efficient gonococcal vaccine,” the research authors wrote.
However Grulich stated the outcomes from a lot of these observational research could also be affected by confounding elements that may affect the outcomes.
“In GoGoVax, our information exhibit that good-quality randomisation was achieved, and other people randomised to obtain vaccine or placebo had balanced ranges of confounding elements,” he stated. “A correctly carried out RCT supplies the strongest doable proof of a cause-and-effect relationship.”
When requested by CIDRAP Information in a follow-up e-mail about what these outcomes imply for international locations which are providing the 4CMenB vaccine to homosexual and bisexual males as a method to stop gonorrhea an infection, Grulich stated he thinks well being authorities making that advice “ought to take into account our findings.”
