Meningitis vaccine offers some defence against gonorrhea, study finds

Researchers studying a mass vaccination campaign against meningitis have found a surprising side-effect — the shots also offered moderate protection against gonorrhea.

Those vaccinated were 31% less likely to contract gonorrhea

In this March 2015 photo, a pharmacist administers the meningitis B vaccine to a University of Oregon freshman during a mass vaccination clinic after an outbreak. A University of Auckland, study says meningitis vaccines might offer moderate cross-protection against gonorrhea. (Brian Davies/The Register-Guard/Associated Press)

Researchers studying a mass vaccination campaign against meningitis have found a surprising side-effect — the shots also offered moderate protection against gonorrhea.

The study, published in The Lancet medical journal, mark the first time immunization has shown any protection against  gonorrhea, and points to new avenues in the search for a gonorrhea vaccine, scientists said.

"This new research could be game-changing," said Linda Glennie, an expert at the Meningitis Research Foundation who was not directly involved in the study.

Gonorrhea has become an increasingly urgent global health problem in recent years as strains of the bacterial infection have developed high levels of drug resistance.

The World Health Organization warned last week that some totally drug-resistance superbug strains of the disease already pose a major threat.

In the study, published in the journal PLoS Medicine, the WHO calls the increase in drug-resistant gonorrhea a "serious situation." The organization said a vaccine "will ultimately be the only sustainable way to achieve control."

No gonorrhea vaccine

Yet so far, efforts to develop a gonorrhea vaccine have yielded disappointing results. Four potential shots have reached the clinical trial stage, but none has been effective, The Lancet said in a press release.

In New Zealand, around one million people under age 20 received a meningitis vaccine known as MeNZB during a 2004-06 immunization program. This provided a valuable opportunity to test for cross-protection, the scientists explained.

Drug-resistant gonorrhea culture are shown under a microscope lens. (Canadian Press)

For their study, the team used data from 11 sexual health clinics for all people aged 15 to 30 who had been diagnosed with gonorrhea or chlamydia, or both, and who had also been eligible to be immunized against meningitis in the 2004-06 campaign.

They found that those who had been vaccinated were significantly less likely to have gonorrhea. And taking into account factors such as ethnicity, deprivation, geographical area and gender, having the MeNZB vaccine reduced the incidence of gonorrhea by around 31 per cent.

A health awareness poster from 1943 warns of the risk from syphilis and gonorrhea. (Hulton Archive/Getty Images)

Those who had been vaccinated and contracted gonorrhea were less likely to have a more severe form of the disease, compared with people who weren't vaccinated.

Helen Petousis-Harris, who co-led the study at the University of Auckland, said the findings "provide experimental evidence and a proof of principle" that meningitis vaccines might offer moderate cross-protection against gonorrhea.

"Our findings could inform future vaccine development for both the meningococcal and gonorrhea vaccines," she said.

Although the diseases have very different symptoms and transmission modes, she said, the bacteria Neisseria gonorrheae and Neisseria meningitidis have an up to 90 per cent genetic match, providing a biologically plausible mechanism.

With files from CBC News