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. Now, there are quite a few patients that are stuck with this STD which everyone considers rather benign -- because it used to be. But not anymore, that's for sure. The good news is that a mass vaccination campaign in New Zealand seems to significantly reduce the likelihood of contracting gonorrhea compared to a control group that didn't receive the vaccine. It's the first time that a vaccine is shown to provide protection against the disease.
More than a century of research has been dedicated to a vaccine for gonorrhea with little success reported. When there was some promising progress, once it reached the clinical trial stage the treatment proved ineffective. It happened on at least four separate occasions. But not this time.
The team led by Dr Helen Petousis-Harris, University of Auckland, New Zealand, administered the meningococcal group B vaccine for a clinical trial that involved 14,000 people. Approximately one million individuals, including 81% of the population under 20 years, received the MeNZB vaccine which targets the Neisseria meningitidis bacteria but works against the Neisseria gonorrhoeae bacteria too, with which it has an 80-90% genetic match. Individuals from Cuba and Norway also received the vaccine.
Researchers reported that vaccinated individuals were far less likely to have gonorrhea than the controls (41% vs 51%). After factoring for such things as ethnicity, gender or geographical area, the team concluded that the MeNZB vaccine reduced the incidence of gonorrhea by 31%.
That might not seem like the best protection but we should all bear in mind these are the first results that show at least some degree of significant protection against the disease. We don't know yet why the vaccine seems to protect some people but not others.
"Our findings provide experimental evidence and a proof of principle that an OMV meningococcal group B vaccine could offer moderate cross-protection against gonorrhoea. This is the first time a vaccine has shown any protection against gonorrhoea. At the moment, the mechanism behind this immune response is unknown, but our findings could inform future vaccine development for both the meningococcal and gonorrhoea vaccines," Peteousis-Harris said in a statement.
The designers of the vaccine initially hand in mind to control meningitis epidemics but once OMV antigens known to prove an immune response to gonorrhea were added, the vaccine proved useful against the STD as well.
Even at a 30% efficacy rate, if immunity is maintained, the vaccine could reduce the prevalence of gonorrhea by more than 30% in the next 15 years. Great protection over a shorter period of time can be achieved by raising the efficacy.
"The potential ability of an OMV group B meningococcal vaccine to provide even moderate protection against gonorrhoea would have substantial public health benefits in view of the prevalence of gonorrhoea, and the increase in antibiotic resistance. If the 4CMenB vaccine, which is currently available in many countries, is shown to have a similar effect to the MeNZB vaccine, then administering it in adolescent immunisation programmes could result in declines in gonorrhoea," said co-author Professor Steven Black, Cincinnati Children's Hospital, USA.
Because so many mutated strains existed around the world -- including some that are totally immune to known antibiotics -- the researchers caution that the vaccine might not work everywhere and thus warrant more research.
Findings appeared in the journal The Lancet.