Gonorrhea is a tricky little germ. Over the decades, it’s managed to outsmart different antibiotics and evolve resistance to many of them. This means we’ve had to adapt how we treat gonorrhea many times. Syphilis and chlamydia are, thankfully, more chill. Treatment for these has remained the same for decades.
We used to think that DoxyPEP offered weak protection from gonorrhea, but more recent research suggests it might not. And while scientists are researching new antibiotics to treat the infection, they’ve also been testing vaccines. Because if we can prevent new cases of gonorrhea, we won’t have to treat them!
One candidate is an existing vaccine that’s used for meningitis B. At this stage, data on how well this works for gonorrhea is mixed – we’re here to guide you through it.
The meningitis B vaccine
When developing vaccines or medicines, one approach is to focus on inventing new drugs. This hasn’t had success for gonorrhea so far. Another approach is to try re-using existing vaccines or treatments for other infections, to see if they’ll work against other germs. Re-purposing like this happens fairly often in medicine: for example, minoxidil to treat hair loss was originally used to treat high blood pressure.
One option for a gonorrhea vaccine is an existing vaccine for a type of meningitis. Meningitis is an infection that can affect the brain, and is most dangerous for children and the elderly. Vaccines for some types of meningitis have been around for decades, but a specific vaccine for meningitis B (4CMenB) was only developed in 2013. It’s given in two doses, four to eight weeks apart.
Since the meningitis B vaccine was approved, some studies and anecdotal reports have suggested it could help protect against gonorrhea. This is because the meningitis B bacteria (Neisseria meningitidis group B) are similar to gonorrhea bacteria (Neisseria gonorrhoeae).
In 2023, the UK was the first country to recommend this vaccine for gay, bisexual and other men who have sex with men who are at higher risk for gonorrhea. It is an approved vaccine in Canada and the US but has not received the same recommendation for gonorrhea prevention. The UK’s decision was based on a survey of evidence at the time, and we’ve got more evidence since then.
Using the meningitis B vaccine this way is “off-label”, which means it’s not what the vaccine was originally intended for.
What does the evidence show?
When British researchers looked through evidence for the meningitis B vaccine to prevent gonorrhea, they found that it was 33-47% effective. This might not sound like much, but 30% is the minimum for a vaccine to be recommended by a public health body. Above this point, a vaccine is seen to have a public health benefit.
Because the meningitis B vaccine is given to young people, most of these studies used data on gonorrhea among this group. This survey used findings from six studies:
- Study 1 analyzed data from young people in Quebec, and showed a 59% drop in gonorrhea cases after the vaccine was introduced
- Study 2 analyzed data from young people in NYC and Philadelphia, and showed a 40% drop in gonorrhea among vaccinated people
- Study 3 showed 33.2% effectiveness among young people in South Australia
- Study 4 used data from Southern California and found 46% reduction among vaccinated young people
- Study 5 in Milan showed a 44.9% drop among vaccinated men who have sex with men, who were also living with HIV
- Study 6 showed a 47% drop in gonorrhea cases among vaccinated young people in Oregon
Amazing, sign me up!
Not so fast. It’s… a little complicated.
Since this British review was released, another study has been published with less exciting results. In this new French study, researchers wanted to see if DoxyPEP and the meningitis B vaccine would have an effect on gonorrhea rates. Their findings were mixed.
In this French study, researchers found that DoxyPEP had some effectiveness against gonorrhea (but it worked a lot better for chlamydia and syphilis, which we’d expect). They observed that the vaccine did not have an effect on gonorrhea rates, and said they would not recommend it.
It gets complicated when we consider that some participants were taking DoxyPEP and the vaccine. This means that when we’re looking at the data, it can be challenging to know which one was having an effect.
What does this mean for me?
Right now, the data is mixed. There are more studies in progress – and when we have these results, we’ll have an even better picture of how well the meningitis B vaccine may work against gonorrhea.
In Canada and the United States, the meningitis B vaccine isn’t offered for free to adults without clear risk factors for meningitis. At this stage, it’s not being recommended as an STI prevention tool in either country. However, adults can still request it from their clinician, but this would cost money if it’s not covered by someone’s private insurance.
Taking the meningitis B vaccine is a personal decision that should be made in collaboration with a qualified healthcare provider. Because the effectiveness is still unclear, there’s no guarantee it will protect against gonorrhea. And it’s important to remember that even if it’s as effective as the U.K. review suggests, this would only reduce risk by a moderate amount. It would not eliminate risk, so testing and treatment for STIs is still essential.
We asked Freddie’s medical director, Dr. Caley Shukalek, for his take. “Overall, there is possible benefit and low risk with this vaccine,” he says. However, “more evidence is definitely needed before it should be recommended across the board.”
