An exisiting vaccine has been shown to reduce the chance of catching gonorrhoea in a world first, raising hopes that people could be immunised against the sexually transmitted infection in future.
A new study of more than 14,000 people found that those who had received a meningitis vaccine in New Zealand had a reduced chance of contracting gonorrhoea compared with unvaccinated people.
The findings, published in The Lancet, showed vaccinated individuals were 31 per cent less likely to catch gonorrhoea than those who had not received a Men B vaccine, adjusting for factors such as deprivation, gender and ethnicity.
The news comes after the World Health Organisation (WHO) warned of the rise of totally untreatable "superbug" strains of gonorrhoea, which has been detected in at least three people worldwide.
Oral sex and a decline in condom use are reportedly behind the spread of the disease, which can infect the genitals, rectum and throat.
According to the WHO, around 78 million people a year are infected gonorrhoea, which in many cases has no symptoms on its own but can lead to pelvic inflammatory disease, ectopic pregnancy and infertility, as well as increasing the risk of getting HIV.
Researchers studied data of all people aged 15 to 30 who had been diagnosed with gonorrhoea or chamydia, or both, at 11 sexual health clinics in New Zealand.
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.
"This is the first time a vaccine has shown any protection against gonorrhoea," said Dr Helen Petousis-Harris, the lead author of the study from the University of Auckland.
"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."
The study said that despite meingitis and gonorrhoea being very different diseases in terms of symptoms and mode of transmission, the bacteria behind them are matched by 80 to 90 per cent.
The development of a gonorrhoea vaccine given to teenagers could become an urgent priority after the WHO said it was "only a matter of time" before last-resort gonorrhoea antibiotics would be of no use.
“Gonorrhoea is a very smart bug,” said Teodora Wi, a human reproduction specialist at the Geneva-based UN health agency.
“Every time you introduce a new type of antibiotic to treat it, this bug develops resistance to it.”
While efforts over the last century to develop a gonorrhoea vaccine have so far been unsuccessful, population data from Cuba, New Zealand and Norway suggests the Men B vaccine could provide protection from the STI.
New Zealand's mass immunisation programme using the Men B vaccine took place from 2004 to 2006.
A total of 14,730 cases were analysed in the study, with 1,241 cases of gonorrhoea, 12,487 cases of chlamydia, and 1,002 cases of co-infection observed by the researchers.