As cases of gonorrhea escalate worldwide and the bacterial culprit (Neisseria gonorrhoeae) develops antibiotic resistance, three studies published in the journal The Lancet Infectious Diseases indicate a widely available, routine childhood vaccine against meningitis could also protect against the sexually transmitted infection. The modeling and observational studies suggest, 4CMenB, a vaccine approved for meningitis, could offer significant protection to young adults and others at increased risk of infection.
More than 80 million new cases of gonorrhea were recorded worldwide in 2020. Gonorrhea, if untreated, can lead to serious health conditions, including infertility in women, transmission to newborn babies, and increased risk of HIV. The lack of a licensed vaccine against the infection has raised concerns that gonorrhea may become intractable.
In the study titled, “Effectiveness of a serogroup B outer membrane vesicle meningococcal vaccine against gonorrhoea: a retrospective observational study,” lead author Winston Abara, PhD, MBBS, and his team compared health records of laboratory-confirmed cases of gonorrhea and chlamydia in 16- to 23-year-olds in New York City and Philadelphia from 2016–2018 with 4CMenB vaccination status and showed that receiving two doses of 4CMenB provided 40% protection against gonorrhea while one dose provided 26% protection.
Abara said, “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. 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.”
Limitations of the study include its non-generalizability, since the source data is limited to a specific age group, and potential misclassification of infection and vaccination status in the surveillance data.
In the study titled, “Effectiveness and impact of the 4CMenB vaccine against invasive serogroup B meningococcal disease and gonorrhea in an infant, child, and adolescent program: an observational cohort and case-control study,” Helen Marshall, MD, a professor of vaccinology at the Women’s and Children’s Hospital in Adelaide, Australia, and her team compared meningitis and gonorrhea infection data from the Australian Communicable Disease Control Branch, and 4CMenB vaccination records from the Australian Immunization Register, to assess the effectiveness of 4CMenB against meningitis and gonorrhea. They found that the two-dose course of 4CMenB is 33% effective against gonorrhea in adolescents and young adults, in addition to being highly effective against meningococcal B meningitis and sepsis.
Marshall said, “While recent studies have provided evidence that 4CMenB vaccination is associated with reduced risk of gonorrhea, the vaccine was only offered to adolescents and young adults for short periods. 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. This information is vital to inform global meningitis vaccination programs and policy decisions.”
Limitations of the study stem from the small number of cases which likely prevented the observation of a corresponding reduction in the rate of gonorrhea among adolescents and young adults.
In the modeling study titled, “Public health impact and cost-effectiveness of gonorrhea vaccination: an integrated transmission-dynamic health-economic modeling analysis,” Peter White, PhD, a professor of public health modeling at Imperial College London, and his team developed a simulation model to compare health impact and cost-effectiveness of a gonorrhea vaccine in three realistic vaccination approaches among men-who-have-sex-with-men (MSM) in England: all men attending sexual health clinics, vaccination following a confirmed gonorrhea diagnosis, or vaccination based on risk of infection.
The authors estimated that vaccinating MSM at the highest risk of gonorrhea infection with 4CMenB would prevent an estimated 110,000 cases in England and save £8 million over a decade.
White said, “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. 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.”
The authors noted that their estimation of the benefit of using 4CMenB to protect against gonorrhea is conservative since the simulation model assumes one dose of the vaccine offers no protection, whereas Abara’s study suggests even a single dose of 4CMenB offers some protection against gonorrhea, thereby increasing the vaccine’s overall benefit. The vaccine will also help combat antimicrobial resistance, further increasing its benefit.
Mingwang Shen, PhD, and Lei Zhang, PhD, who were not involved in the study said, “The key message of White’s study is that vaccination using the 4CMenB vaccine according to the risk of the targeted MSM population is likely to be cost-effective, even if the vaccine were to have a relatively low efficacy and a short duration of protection. Such a strategy should be recommended and rolled out in a high-income country setting such as England.”
Jason Ong, PhD, Magnus Unemo, PhD, Annabelle Choong, Victor Zhao, and Eric Chow, PhD, who were not involved in the studies, noted that while efforts to develop a gonorrhea vaccine continue, “We must continue to strengthen prevention efforts, improve access to early diagnosis and evidence-based treatment through indexing cases and sexual contacts, ensure quality-assured global surveillance systems to inform treatment guidelines, and invest in rapid, reliable point-of-care tests for detection of gonorrhea and its antimicrobial resistance, and the development of novel therapeutic antimicrobials.”