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Results from a major randomised control trial have provided strong evidence that the meningococcal B vaccine does not effectively prevent gonorrhoea among gay and bisexual men. The study, conducted by Griffith University’s Institute for Biomedicine and Glycomics and the Kirby Institute at UNSW Sydney, challenges previous observational studies suggesting a potential benefit.
The findings were presented by Professor Kate Seib from Griffith University at the Conference on Retroviruses and Opportunistic Infections in Denver, Colorado. Gonorrhoea remains a significant public health challenge, particularly due to rising antibiotic-resistant strains. The study focused on gay and bisexual men, who are at a higher risk of contracting the infection.
Study Details and Findings
The double-blind, randomised, placebo-controlled trial involved 587 gay and bisexual men who received either the meningococcal vaccine or a saline placebo. According to Professor Seib, the incidence of gonorrhoea was virtually identical across both groups, at approximately 48 percent per year, indicating that the vaccine had no effect on preventing the disease.
“Our results support findings from the smaller DOXYVAC open-label trial that also showed no effect. Taken together, these two studies provide strong evidence that the 4CMenB meningococcal vaccine is not effective at preventing gonorrhoea in gay and bisexual men who are at high risk of contracting it,” said Prof. Seib.
The trial was conducted among individuals with a recent history of gonorrhoea or syphilis, chosen due to their higher likelihood of acquiring gonorrhoea during the study period. This specific population may have influenced the results, as their high rates of previous infections could potentially reduce any protective effects of the vaccine.
Implications for Public Health
Professor Andrew Grulich from the Kirby Institute, another lead on the study, expressed disappointment over the findings, noting that an effective vaccine could transform prevention strategies. Despite the vaccine’s ineffectiveness against gonorrhoea, it remains a safe and effective measure against meningococcal disease.
“We want men who have received the 4CMenB vaccine in the hope of gonorrhoea prevention to know that the vaccine is very safe and they will have protection against some meningococcal strains. However, these men will need to explore other options for prevention of acquisition of gonorrhoea, such as condoms and regular testing,” Prof. Grulich stated.
The study’s results highlight the importance of alternative prevention methods, such as sexual health clinics and community-based testing services, which remain crucial in combating the spread of gonorrhoea.
Understanding the Discrepancy with Observational Studies
The RCT, named ‘GoGoVax’, was initiated following several observational studies that suggested the meningococcal B vaccine might reduce gonorrhoea incidence. However, observational studies can be influenced by confounding factors, which may lead to misleading conclusions.
“Some case-control studies have compared the meningococcal B vaccination history of people who have gonorrhoea to those with chlamydia. In these studies, people who acquired gonorrhoea had lower 4CMenB vaccination rates than expected, suggesting the vaccine may have prevented gonorrhoea. However, other confounding factors might explain the differences,” explained Prof. Grulich.
RCTs are considered the gold standard in medical research because they eliminate potential confounding factors through randomisation. The GoGoVax trial demonstrated good-quality randomisation, providing robust evidence against a cause-and-effect relationship between the vaccine and gonorrhoea prevention.
Looking Forward
Despite the disappointing outcome, the study underscores the importance of continued research and community engagement in exploring new prevention strategies for gonorrhoea. Brent Mackie, Director of Policy, Strategy and Research at ACON, emphasized the value of such research in refining approaches to STI prevention.
“Research like this is vital because it helps give our communities the clarity we need. Findings help us refine our approach in preventing the transmission of STIs. We thank everyone who participated in the study. Your contribution will help strengthen sexual health in our communities,” Mackie said.
As the search for effective prevention methods continues, the study serves as a critical reminder of the complexities involved in combating sexually transmitted infections and the need for innovative solutions.
