Protection site

MenB vaccine provides moderate protection against gonorrhea

A widely approved vaccine for meningitis may provide up to 40% protection against gonorrhea in young adults and adolescents, according to new research. This moderate efficacy combined with a targeted risk-based approach could reduce cases and lead to health care savings over 10 years, an additional modeling study has shown.

The findings – in three linked papers – were published April 12 in The Lancet Infectious Diseases.

Gonorrhea, caused by bacteria Neisseria gonorrhoeaeis the second most commonly reported sexually transmitted infection in the United States, according to the Centers for Disaster Control and Prevention. Globally, the World Health Organization estimates that there were 82.4 million new cases in people between the ages of 15 and 49 in 2020. At the same time, it is becoming more difficult to treat the infection due to the increasing prevalence of drug-resistant strains of N gonorrhea.

“New approaches, such as vaccination, are needed as long-term strategies to prevent gonorrhea and address the emerging threat of antimicrobial resistance,” wrote Winston Abara, MD, PhD, Division of Prevention of STDs, Centers for Disease Control and Prevention, and colleagues. .

Although there is currently no vaccine for gonorrhea, observational studies have found an association between a serogroup B meningococcal vaccine and a reduction in cases of gonorrhea. A study in New Zealand found that people vaccinated with the MeNZB vaccine, which was produced to control an epidemic of meningococcal disease in the country, were 31% less likely to contract gonorrhea.

This cross-reactivity occurs because Neisseria meningitidisthe bacteria responsible for meningitis, is closely related to N gonorrhea, Joseph Alex Duncan, MD, Ph.D.associate professor of medicine, Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, said Medscape Medical News. He did not participate in the research. The idea is that “a large part of the proteins contained in the vaccine also recognize the proteins of Gonorrhea in Neisseria because bacteria are so similar at a genetic level,” he said.

To see if this association was still found for the four-component serogroup B (MenB-4C) meningococcal vaccine, which is now widely available, Abara and colleagues reviewed health records to identify confirmed gonorrhea and chlamydia infections. in the laboratory in adolescents and young adults. in New York and Philadelphia. All individuals included in the analysis were between the ages of 16 and 23, and all infections occurred between January 1, 2016 and December 31, 2018. These infections were then linked to vaccination records to determine MenB- vaccination status. 4C of individuals. Full vaccination was defined as two doses of MenB-4C given 30-180 days apart.

The research team identified more than 167,700 infections, including 18,099 gonococcal infections, 124,876 chlamydia infections, and 24,731 co-infections, among 109,737 individuals. A total of 7692 people had received at least one vaccine injection and 3660 people were fully vaccinated. Complete MenB-4C vaccination was estimated to be 40% protective (APR 0.60; P ; P = 0.0012).

“The results of our study add to the body of evidence that demonstrates that MenB-4C can provide cross-protection against Neisseria gonorrhoeae and it supports the feasibility of an effective gonococcal vaccine with implications for prevention and control. gonorrhea,” Abara said. Medscape Medical News.

A second study conducted in South Australia examined the effectiveness of the MenB-4C vaccine against meningitis and gonorrhea as part of a vaccination program. Using infection data from the South Australian government and vaccination records from the Australian Immunization Registry, researchers identified people born between February 1, 1998 and February 1, 2005, with gonorrhea or infection with chlamydia documented between February 1, 2019 and January 31. , 2021. Individuals with chlamydia served as controls to account for similar sexual behavioral risks.

Analysis included 512 people with 575 cases of gonorrhea and 3140 people with 3847 episodes of chlamydia. In this group, the estimated effectiveness of the gonorrhea vaccine was 32.7% (95% confidence interval [CI]8.3 – 50.6) in fully vaccinated people and 32.6% (95% CI, 10.6 – 49.1) in those who had received at least one dose of MenB-4C.

Although these results are “confirmatory” because they showed similar results to previous observational studies, they are still exciting, Duncan said. “So far, we really haven’t made any real progress in knowing what kind of immune responses might actually protect against disease,” he said. “These observational studies have really reinvigorated the Gonorrhea in Neisseria vaccine research community.

A moderately effective vaccine — like the protection shown in the two studies — could lead to a significant reduction in cases, he noted. A 2015 Australian modeling study estimated that a non-declining vaccine with 20% efficacy could reduce cases by 40% over 20 years. Focusing on vaccinating high-risk groups could also have an “outsized impact”, said Jeanne Marrazzo, MDdirector, Division of Infectious Diseases, UAB Medicine, Birmingham, Alabama, in an interview with Medscape Medical News. In the third study published in The Lancet, the researchers estimated possible case reduction and potential health care cost savings in England in a vaccination effort focused on men who have sex with men (MSM) at high risk of gonorrhea infection. They predicted that a vaccine with 31% efficacy could prevent 110,200 cases among MSM and save around £8 million ($10.4 million) over 10 years.

Duncan and Marrazzo agreed that clinical trials are needed to determine if the decrease in gonorrhea cases is due to the MenB-4C vaccine or if the association is coincidental. Two clinical trials are underway, one in Australia and one in the United States. Marrazzo leads the US multicenter study, which also has two sites in Bangkok, Thailand. The trial will also examine whether vaccine protection varies according to the location of the gonococcal infection: urethra, rectum, cervix or pharynx. The two new observational studies did not distinguish between different sites of infection.

Marrazzo’s trial has so far recruited nearly 500 people, with the goal of enrolling more than 2,000 participants in total. She hopes to see results by the end of 2023. “It’s quite an ambitious effort, but hopefully it will not only give us a definitive answer in terms of reducing infection per anatomical site,” he said. she said, but “will also give us a lot of information about how the immune response works to protect you against gonorrhea if you get the vaccine.”

Duncan has received research grants from the National Institutes of Health. Marrazzo is leading a clinical trial of the MenB-4C vaccine sponsored by the National Institute of Allergy and Infectious Diseases.

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