A trio of studies are suggesting that vaccines already in use to prevent meningitis could also provide some level of protection against untreatable gonorrhea, something that could be key considering rising rates of the disease in Canada.
The three research papers, all published Tuesday in the Lancet Infectious Diseases, found that a specific meningitis vaccine provided 33-40 per cent protection against gonorrhea, and that vaccine campaigns targeted to this issue might prevent thousands of cases and save millions of dollars.
Gonorrhea is a sexually transmitted bacterium that can be spread through oral, vaginal and anal intercourse. If untreated, it could lead to complications such as infertility, joint pain, an increased risk of HIV/AIDS, and complications in infants if a parent has gonorrhea while pregnant.
There is currently no approved vaccine specifically for gonorrhea. But while gonorrhea has traditionally been treated with various antibiotics, in recent years the bacterium has developed a resistance to the majority of these antibiotics, leading to an increase in untreatable or treatment-resistant gonorrhea — a worrisome development considering how common gonorrhea is.
Previous research has suggested that there may be some protection against gonorrhea to be found in vaccines that prevent meningitis, which is a sometimes fatal swelling of the membranes around the brain and spinal cord, often caused by a bacterial infection.
There are a variety of meningococcal vaccines that prevent infection by Neisseria meningitidis, a bacterium that causes meningitis and sepsis.
In Canada, it is recommended that children receive a meningococcal vaccine that protects against the meningitis groups A and C when they reach 12 months old. Teenagers may receive that vaccine or another vaccine that protects against A,C,Y and W groups. For those who are at a higher risk of meningitis, the 4CMenB vaccine that protect against the meningitis serogroup B may be considered on an individual basis.
In these three new studies, researchers wanted to look closer at whether these vaccines can help protect against gonorrhea, focusing on the 4CMenB vaccine in particular.
In the first study, researchers looked at health records regarding to gonorrhea and chlamydia among 16-23 year-olds in two American cities between 2016 and 2018, then compared those records to see who was vaccinated with 4CMenB at the time of their infection.
Among 110,000 people in the study sample, there were more than 167,000 infections, including 18,000 gonorrhea infections and 24,700 infections of gonorrhea and chlamydia at the same time.
Around 7,700 people had received the 4CMenB vaccine, and researchers found that having two doses of this vaccines provided 40 per cent protection against gonorrhea, while one dose provided 26 per cent protection.
“Our findings suggest that meningitis vaccines that are even only moderately effective at protecting against gonorrhea could have a major impact on prevention and control of the disease,” Dr. Winston Abara, a scientist with the U.S. Centers for Disease Control and Prevention and the study lead, said in a press release. “Clinical trials focused on the use of 4CMenB against gonorrhea are needed to better understand its protective effects and could also offer important insights towards the development of a vaccine specifically for gonorrhea.”
The second study had similar findings when assessing the effectiveness of 4CMenB against gonorrhea as part of a vaccination campaign for children and adolescents.
The setting was South Australia’s ongoing 4CMenB’s immunization program, which the release called “the most extensive globally.”
Researchers compared meningitis and gonorrhea infection data to the vaccination records from the Australian Immunization Record starting in 2018. They used patients who had come down with chlamydia as a control due to the cohort similarities between those at risk of gonorrhea and those at risk of chlamydia.
In the first two years of the immunization program, more than 53,000 teenagers and younger adults received at least one dose of 4CMenB, and researchers found that two doses of the vaccines was 33 per cent effective against gonorrhea.
Helen Marshall, a professor at the University of Adelaide and lead of this study, pointed out that previous research in this area has been on a smaller scale and often looking only at a short period of time.
“The unprecedented scale of South Australia’s 4CMenB vaccination program offers valuable real-world evidence of the vaccine’s effectiveness against meningococcal B meningitis in children and adolescents, and gonorrhea in adolescents and young people,” she said in the release. “This information is vital to inform global meningitis vaccination programs and policy decisions.”
Marshall, as one of the leading researchers of vaccination in Australia, is working on more research into this field, including a project providing meningitis vaccines for free to youth in the Northern Territory in Australia to continue studying its potential protection against gonorrhea. Normally it costs around $300 in Australia to get two doses of the meningitis vaccine outside of regular childhood immunization.
The third and final study brought public policy into the question.
Researchers in the U.K. used modelling to analyze three different potential vaccination campaigns — meningitis vaccination of all men who attended a sexual health clinic, vaccination following a confirmed diagnosis of gonorrhea and vaccination based on a patient’s assessed level of risk of potentially catching gonorrhea.
According to the release, it is the first study to assess not only the health impact but the cost-effectiveness of using a meningitis vaccine to cut gonorrhea infections.
The modelling showed that vaccinating patients based on risk level would prevent an estimated 110,000 cases and save eight million pounds, or roughly C$13 million, over 10 years.
“With a gonorrhea-specific vaccine likely to take years to develop, a key question for policymakers is whether the meningitis vaccine 4CMenB should be used against gonorrhea infection,” Peter White, a professor with Imperial College Lonson and lead author of the study, said in the release. “Our analysis suggests that giving the vaccine to those at the greatest risk of infection is the most cost-effective way to avert large numbers of cases.”
For all three studies, researchers acknowledge there were limitations, including small sample groups in terms of age, and some unknowns in modelling vaccination campaigns.
But their takeaway is that there is growing evidence that governments should consider looking at meningitis vaccines as a potential tool in the fight against gonorrhea.
Although 33-40 per cent protection may not sound like a lot, when an infection is as common as gonorrhea, it means more than it seems. In Canada, more than 30,000 cases of gonorrhea were reported in 2018 alone.
And officials are worried that those numbers are only increasing. Last month, New Brunswick’s chief medical officer of health flagged that gonorrhea rates are on the rise, stating that there were five times more confirmed cases in 2021 in the province than there were the year before.