From the Journals

OMV meningococcal vaccine also protected against gonorrhea

Publish date: July 10, 2017
By
Mary Ann Moon

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‘A step in the right direction’

Over decades of research, all of the attempts to create a vaccine against gonorrhea have failed, largely because of the variable nature of Neisseria gonorrhoeae antigens and the failure of the bacteria to induce a protective immune response, so the findings of Dr. Petousis-Harris and her associates are “a step in the right direction” and should reinvigorate interest and investment in this endeavor.

Although MeNZB is no longer available, another meningococcal vaccine (4CMenB, Bexsero) contains the same outer-membrane-vesicle antigen and three of the same recombinant proteins. As the authors pointed out, immunizing adolescents with this vaccine could reduce the rate of gonorrhea substantially, even if it has only moderate efficacy and duration of effect. In particular, reducing the pool of asymptomatic carriers would decrease both transmission and the severe sequelae that develop when the infection goes undetected.

Kate L. Seib, PhD, is a microbiologist at the Institute for Glycomics at Griffith University in Southport, Australia. She reported support by a career development fellowship from the Australian National Health and Medical Research Council. Dr. Seib made these remarks in an accompanying editorial comment (Lancet. 2017 July 10. doi: 10.1016/S0140-6736(17)31605-7).


 

FROM THE LANCET

A group B meningococcal outer-membrane-vesicle (OMV) vaccine used during a meningitis outbreak in New Zealand also protected against gonorrhea, according to a report published online July 10 in the Lancet.

Even though Neisseria meningitidis and Neisseria gonorrhoeae cause distinctly different diseases, the bacteria are closely related and are genetically and antigenically very similar. Most of the virulence factors present in one pathogen have an equivalent in the other, “providing at least one biologically plausible mechanism for cross-protection,” said Helen Petousis-Harris, PhD, of the department of general practice and primary health care, University of Auckland (New Zealand), and her associates.

Vaccine syringe copyright luiscar/Thinkstock

Approximately 1 million people – 81% of the New Zealand population younger than 20 years – received almost 3 million doses of the OMV meningococcal B vaccine (MeNZB) in a 2-year mass immunization program during the outbreak, allowing the investigators to compare the rate of gonorrhea between vaccinated and unvaccinated people. They performed a retrospective case-control study involving 14,730 participants, using information from a national health care database, a national immunization registry, and 11 sexual health clinics covering diverse geographic regions. This included 1,241 cases of gonorrhea (cases), 12,487 cases of chlamydia (controls), and 1,002 cases of gonorrhea plus chlamydia coinfection (categorized as controls or cases in separate analyses).

“The adjusted estimate for vaccine effectiveness of the MeNZB against confirmed cases of gonorrhea” was 31% (95% confidence interval, 21-39; P less than .0001), a finding that remained robust across several sensitivity analyses, Dr. Petousis-Harris and her associates said (Lancet. 2017 July 10. doi: 10.1016/S0140-6736(17)31449-6).

“To our knowledge, ours is the first study to show an association between a vaccine and a reduction in the risk of gonorrhea,” they noted. “The potential ability of an OMV group B meningococcal vaccine to provide even modest protection against gonorrhea would have substantial public health benefits in view of the prevalence of gonorrhea. Modeling suggests that a vaccine with 30% efficacy could decrease the prevalence of gonorrhea by more than 30% within 15 years, if immunity is maintained.”

These findings also are important in view of the organism’s increasing resistance to existing antibiotics. Moreover, if further study confirms that the MeNZB vaccine offers some degree of cross-protection against gonorrhea, these data can inform the development of a gonorrhea vaccine, the investigators added.

This study was funded by GlaxoSmithKline Vaccines and Auckland UniServices. Dr. Petousis-Harris reported serving as a consultant for GSK, Merck, and Pfizer, and one of her associates reported ties to Novartis Vaccines, GSK, Protein Sciences, and Merck.

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