"Mathematical modeling has shown that even a vaccine of moderate efficacy and duration could have a substantial effect on the transmission and prevalence of gonorrhea, if coverage in the population is high and protection lasts during the highest risk period", Kate Seib, of Australia's Institute for Glycomics, wrote in a commentary that accompanied the study.
The UN health agency estimates that 78 million people are infected with gonorrhoea every year.
As we reported earlier today, the world is slowly losing the battle with gonorrhea Some bacterial strains that cause gonorrhea seem to have garnered immunity to virtually all the antibiotics we can throw at them, and infection rates aren't slowing down.
It's also not clear how long the immune response might last, Petousis-Harris said.
"This is the first time a vaccine has shown any protection against gonorrhoea", lead author Helen Petousis-Harris from University of Auckland, New Zealand, said in a statement.
Observers had noted that gonorrhea incidence appeared to fall after the vaccination campaign, so Petousis-Harris' group chose to see if they could quantify the effect using a case control study of patients at sexually transmitted infection (STI) clinics in New Zealand.
The reason for this, they speculate, is because the bacteria that causes meningitis is a very close relative of the species that causes gonorrhoea, and the jab was giving cross-protection. It's the first time a vaccine has shown any protection against the sexually transmitted infection.
Around one million people, or 81 per cent of the New Zealand population under 20 years old, received a vaccine against meningococcal group B (Men B), a bacteria can cause meningitis and blood poisoning if it enters the body. Among more than 14,700 cases and controls for analyses, there were 1,241 incidences of gonorrhea, 12,487 incidences of chlamydia, and 1,002 incidences of coinfection. All were eligible to get the MeNZB vaccine. By mimicking bacterial bits released as the bugs proliferate, the vaccine trains the immune system to recognize and attack the bacteria.
The New Zealand vaccine is no longer available, but the same membrane-attacking component has been incorporated in a new vaccine targeting a broad range of group B Neisseria meningitidis.
The researchers don't yet know what part of the MeNZB vaccine may be protective against gonorrhea.
It's worth noting our study likely underestimated the vaccine's effectiveness, and also while they need to be tested, the other aforementioned vaccines may be more effective than MeNZB. The indication that something in the MeNZB vaccine might increase protection against gonorrhoea requires further research to pinpoint how it does so.
It would make sense, says Black, to consider offering meningitis B vaccination to such groups now - although they are typically more hard for doctors to reach with medical treatments. "It might be that we've got a vaccine out there that could make a significant difference".
Researchers in Quebec say they saw the same phenomenon after a meningitis outbreak there, and previously published data from Cuba and Norway also hint of the vaccine's unexpected benefit.
The research was funded by GSK Vaccines, a pharmaceutical company, and Auckland UniServices, a branch of the university that partners academics with industry.
"Gonorrhoea is a very smart bug", said Teodora Wi, a human reproduction specialist at the Geneva-based United Nations health agency. But a vaccine couldn't be evaded so easily.
A meningococcal group B vaccine has been found to offer protection against gonorrhea, report researchers.