A new study has found that an existing meningitis vaccine could be used to help protect against gonorrhea amid rising global cases and growing bacterial resistance to drugs.
Gonorrhea is a sexually transmitted infection that, if not treated, can lead to serious health conditions, including female infertility, transmission to newborns and an increased risk of HIV infection.
According to the World Health Organization (WHO), in 2020 more than 80 million new cases of infection were registered worldwide.
Researchers suggest the declining effectiveness of treatments for the bacteria responsible – Neisseria gonorrhoeae – and the lack of a licensed vaccine to prevent the infection, raising concerns about the possibility that gonorrhea may become more resistant to treatment, or even untreatable, in the future.
In 2016, the World Health Organization set a goal of reducing the incidence of gonorrhea by 90% by 2030, however an effective vaccine has not yet been developed.
Three new studies suggest that the 4CMenB meningitis vaccine may offer significant protection for young men, and for men who have sex with men who may be at greater risk of infection.
To date, no study has evaluated both the health impact and cost-effectiveness of using a vaccine to prevent gonorrhea.
The modeling study led by Professor Peter White, Imperial College London, was the first to analyze the health and economic impacts of using a vaccine to protect against gonorrhea that would explain its impact on future infection rates.
A simulation model was developed to compare three realistic vaccination methods among men who have sex with men (MSM) in England.
These were to vaccinate all men who go to sexual health clinics, vaccinate after a confirmed gonorrhea diagnosis, or vaccinate based on the risk of infection.
Based on their analysis and a balance of prevented cases against the cost of vaccination, the researchers recommend that MSM at highest risk of developing gonorrhea be vaccinated with 4CMenB, which would prevent an estimated 110,000 cases and save £8 million over 10 years.
Professor Peter White said: “With the development of a gonorrhea vaccine potentially taking years, a key question for policy makers is whether the 4CMenB meningitis vaccine should be used against gonorrhea infection.
“Our analysis indicates that giving the vaccine to those at high risk of infection is the most cost-effective way to avoid large numbers of cases.”
A study of the efficacy of the 4CMenB vaccine against meningitis in a large-scale vaccination program in South Australia reports that two doses of the vaccine are 33% effective against gonorrhea in adolescents and young adults.
Professor Helen Marshall, Women’s and Children’s Hospital in Adelaide, Australia, said: “While recent studies have provided evidence that the 4CMenB vaccine is associated with a reduced risk of gonorrhea, the vaccine has only been offered to adolescents and young adults for short periods.
“The unprecedented scale of the 4CMenB vaccination program in South Australia provides valuable real-world evidence of vaccine efficacy against meningococcal B meningitis in children and adolescents, and gonorrhea in adolescents and young adults. This information is vital to inform global meningitis vaccination programs and policy decisions.”
While a study of the health records of children aged 16-23 years in New York City and Philadelphia in the United States, during 2016-2018, two doses of the same vaccine provide 40% protection against gonorrhea.
Dr Winston Apara, of the US Centers for Disease Control and Prevention, said: “Our findings suggest that meningitis vaccines that are only moderately effective in protecting against gonorrhea can have a significant impact on disease prevention and control.
“Clinical trials focused on the use of 4CMenB against gonorrhea are needed to better understand its protective effects and could also provide important insights toward developing a customized gonorrhea vaccine.”
The results are published in three linked papers published in The Lancet Infectious Diseases Journal.