Meningococcal Vaccine May Provide Immunity Against Gonorrhea

July 10, 2017

Use of an outer membrane vesicle (OMV) meningococcal B vaccine (MeNZB) may provide some level of cross-protection against gonorrhea, according to a new study. The novel findings provide proof of concept for further gonorrhea vaccine research.

"The potential ability of a vaccine to provide even moderate protection against gonorrhea is of substantial public health interest, in view of the prevalence of gonorrhea and the increase in antibiotic resistance," write Helen Petousis-Harris, PhD, from the University of Auckland, New Zealand, and colleagues.

As part of a retrospective case-control study, researchers evaluated data from 11 national sexual health clinics in New Zealand to determine the incidence of confirmed gonorrhea and chlamydia cases among individuals aged 15 to 30 years who received a 3-dose primary series of MeNZB between 2004 and 2008. All patients received the vaccine when they were aged less than 20 years, and confirmed gonorrhea cases were diagnosed between January 1, 2004, and December 31, 2016. Individuals with only positive chlamydia tests were used as a control group.

During the 12-year study period there were 14,730 cases available for analysis. These included 1241 cases of gonorrhea, 12,487 cases of chlamydia, and 1002 cases of coinfection with both.

Patients who had received all 3 doses of the MeNZB vaccine were 41% less likely to test positive for gonorrhea vs chlamydia alone (41% [511/1241] vs 51% [6424/12487], adjusted odds ratio 0.69; 95% confidence interval [CI], 0.61 - 0.79; P < .0001).

After adjusting further for factors such as ethnicity, geographic area, income, and sex, the researchers found that those vaccinated with the MeNZB vaccine were 31% less likely to be diagnosed with gonorrhea compared with chlamydia (95% CI, 21 -39%; P < .0001).

"Further evidence is needed to support the hypothesis that the N meningitidis outer membrane vesicle vaccine provides cross-protection against N gonorrhoeae," Kate L. Seib, PhD, a microbiologist from Griffith University in Gold Coast, Australia, writes in an accompanying editorial. "Nonetheless, the reduced gonococcal rates after MeNZB vaccination support the feasibility of a vaccine to protect against gonorrhoea."

She continues on to say that whereas a 31% vaccine efficacy might not make a strong case for its widespread use, "modeling studies have suggested that a vaccine with even moderate efficacy and duration of coverage could have substantial effects on transmission under the right circumstances."

The study authors acknowledge that the findings in this study may not be generalizable to the overall population, as not all people with gonorrhea will seek care at a sexual health clinic, but may instead consult their primary care physician. The authors also note that while those seeking care at a sexual health clinic may differ in age, socioeconomic status, or sexual behaviors, the possible higher risk for sexually transmitted disease in this population may actually underestimate the effect of the vaccine on the wider population.

Given that the MeNZB vaccine is no longer available, the researchers postulate that new meningococcal vaccines with the same OMV may still provide cross-protection against a related organism and suggest that this new data provides "proof of principle" that may inform future vaccine development.

Funding for this study was provided by GSK Vaccines and Auckland UniServices.

Dr Petousis-Harris has been a consultant for GlaxoSmithKline, Merck, and Pfizer but has not received honoraria. Dr Black has been a consultant for Novartis Vaccines, and is currently a consultant for GlaxoSmithKline, Protein Sciences, Merck, and the World Health Organization. All other authors and the editorialist have disclosed no relevant relationships.

Lancet. Published online July 10, 2017. Study, Editorial

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