Three research papers identify effective ways to improve protection against gonorrhea infections in the face of rising cases and increasing drug resistance.
An observational study of the efficacy of 4CMenB in a large-scale vaccination program in South Australia indicates that two doses of the vaccine are 33% effective against gonorrhea in adolescents and young adults.
An observational study of health records of 16- to 23-year-olds in New York City and Philadelphia, USA, during 2016-2018 indicates that receiving two doses of the 4CMenB meningitis vaccine provides 40% protection. against gonorrhea.
Meningitis vaccines could help improve protection against gonorrhea amid rising cases globally and increasing bacterial resistance to drugs used to treat the infection, according to findings from three linked papers published in the journal The Lancet Infectious Diseases .
Gonorrhea is a sexually transmitted infection (STI) that, if left untreated, can lead to serious health problems, including infertility in women, transmission to newborns, and an increased risk of contracting HIV. More than 80 million new cases of gonorrhea were recorded worldwide in 2020.
The declining effectiveness of drug treatments for the responsible bacteria, Neisseria gonorrhoeae, and the lack of a licensed vaccine to prevent infection have raised concerns that gonorrhea may become more resistant to treatment, or even untreatable, in the future.
The WHO has recommended meningitis vaccines as part of its roadmap to reduce the global burden of meningitis. This includes offering meningitis vaccines as part of routine childhood immunization strategies. As meningitis vaccines become more available, studies have shown that they also offer some protection against gonorrhea, and that even partial protection could greatly reduce cases of infection. However, questions remain about the impacts and effectiveness of using meningitis vaccines against gonorrhea.
In 2016, the WHO set a goal to reduce the incidence of gonorrhea by 90% by 2030; however, an effective vaccine has not yet been developed. All three studies suggest that the 4CMenB vaccine may offer significant protection to young adults and men who have sex with men who may be at higher risk of infection.
4CMenB meningitis vaccine provides 40% protection against gonorrhea
An observational study led by Dr. Winston Abara of the U.S. Centers for Disease Control and Prevention used health records to identify laboratory-confirmed cases of gonorrhea and chlamydia, another major STI, among young people. 16 to 23 years in New York City, NY and Philadelphia, PA, from 2016 to 2018. These cases were compared to immunization records to determine the vaccination status of individuals with 4CMenB, which is licensed for use against meningitis , at the time of infection.
There were more than 167,000 infections (18,099 gonorrhea, 124,876 chlamydia, and 24,731 coinfections) among nearly 110,000 people. A total of 7,692 people had received the 4CMenB vaccine, of whom 4,032 (52%) received one dose, 3,596 (47%) received two doses, and 64 (less than 1%) received more than two doses. Full vaccination with 4CMenB (receiving two doses) was estimated to provide 40% protection against gonorrhea. One dose of vaccine provided 26% protection.
Dr Winston Abara said: “Our findings suggest that meningitis vaccines that are moderately effective in protecting against gonorrhea could have a major impact on preventing and controlling the disease. “Clinical trials focusing on the use of 4CMenB against gonorrhea are needed to better understand its protective effects and could also provide important information for the development of a gonorrhea-specific vaccine.”
The authors acknowledge some limitations. The findings may not be generalizable to broader groups because the data used came from people ages 16 to 23 in two large urban settings in the U.S. Additionally, the use of surveillance data means that it is possible The infection and vaccination status of some participants was incorrectly classified, which would affect the analysis.
Two-dose course of 4CMenB is 33% effective against gonorrhea in adolescents and young adults
South Australia’s 4CMenB rolling vaccination program is the largest globally and initially involves infants, children, adolescents and young adults with a state-funded rolling program for infants and adolescents In an observational study led by Professor Helen Marshall, from the Adelaide Women’s and Children’s Hospital, researchers evaluated the effectiveness of 4CMenB against meningitis and gonorrhea as part of a vaccination program for infants, children and adolescents.
The authors analyzed meningitis and gonorrhea infection data held by the Communicable Disease Control Branch and 4CMenB vaccination records from the Australian Immunization Registry. To estimate the efficacy of 4CMenB against gonorrhea, patients diagnosed with chlamydia served as controls due to similar sexual behavior risks reported in patients with either infection.
More than 53,000 adolescents and young adults received at least one dose of 4CMenB during the first two years of the vaccination program. In addition to being highly effective against meningococcal meningitis B and sepsis, in adolescents and young adults, a two-dose course of 4CMenB was 33% effective against gonorrhea
Professor Helen Marshall said: “While recent studies have provided evidence that the 4CMenB vaccine is associated with a 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 provides valuable real-world evidence of vaccine efficacy against meningococcal meningitis B in children and adolescents, and gonorrhea in adolescents and young people. “This information is vital to inform global meningitis vaccination programs and policy decisions.” [3]
The authors acknowledge some limitations . While no significant reduction in the rate of gonorrhea was observed among adolescents and young adults, this was likely due to the small number of cases in this age group. The reported effectiveness of 4CMenB against gonorrhea is consistent with other studies.
Gonorrhea and chlamydia coinfections may play an important role in the spread and severity of the disease, but factors associated with coinfection rates are not well understood. However, the analysis shows that the effectiveness of 4CMenB was similar whether coinfections were included or not.
Writing in a commentary linked to both observational studies, Professor Jason Ong, Dr Magnus Unemo, Annabelle Choong, Victor Zhao and Dr Eric Chow, who were not involved in the studies, highlight key measures to be taken while efforts to develop a vaccine against gonorrhea continue: “In the meantime, we must continue to strengthen prevention efforts, improve access to early diagnosis and evidence-based treatment (index cases and sexual contacts), ensure quality global surveillance systems guaranteed to inform treatment guidelines and invest in fast and reliable systems. point-of-care testing (for the detection of N. gonorrhoeae and its antimicrobial resistance) and the development of new therapeutic antimicrobials.”
Vaccination based on infection risk could prevent 110,000 cases in England and save £8m over 10 years
Until now, no study has evaluated both the health impact and cost-effectiveness of using a vaccine to prevent gonorrhea infections.
A modeling study led by Professor Peter White, Imperial College London, UK, is the first analysis of the health and economic effects of using a vaccine to protect against gonorrhea that explains its impact on future infection rates.
A simulation model was developed to compare three realistic vaccination approaches among men who have sex with men (MSM) in England: vaccination of all men attending sexual health clinics; vaccination after a confirmed diagnosis of gonorrhea; or vaccination based on the risk of infection.
Based on their analysis and a balance of cases prevented against the cost of vaccination, the authors recommend vaccinating MSM at highest risk of gonorrhea infection with 4CMenB, which would prevent approximately 110,000 cases and save £8 million over 10 years.
Professor Peter White said: “Given that a specific gonorrhea vaccine is likely to take years to develop, a key question for policymakers is whether the 4CMenB meningitis vaccine should be used against gonorrhea infection. “Our analysis suggests that giving the vaccine to people at highest risk of infection is the most cost-effective way to prevent large numbers of cases.” [3]
The authors explain that their estimate of the benefit of using 4CMenB to protect against gonorrhea is conservative. Due to lack of data at the time of the study, it was assumed that a first dose of vaccine offers no protection, so only those who received a second dose were protected; However, the study by Abara and colleagues suggests that one dose offers some protection, increasing the benefit of vaccination.
Additionally, vaccination will reduce the future impacts of antimicrobial resistance (AMR), which are likely to be substantial, meaning that vaccination would be even more beneficial than currently estimated, but more studies are needed to assess the potential burden. future of AMR.
Writing in a linked commentary, Dr Mingwang Shen and Dr Lei Zhang, who were not involved in the study, highlight the importance of the findings reported by Professor Peter White and colleagues, saying: "The key message of the study is that vaccination with the 4CMenB vaccine according to the risk of the target MSM population is likely to be cost-effective, even if the vaccine had relatively low efficacy and short duration of protection. Such a strategy should be recommended and implemented in a country setting high-income like England.”
