For years, the MenB vaccine — widely known by its commercial name, Bexsero — has been a staple of childhood immunisation in the UK, protecting infants from meningococcal group B disease. Quietly, however, this same vaccine may be offering an unexpected line of defence against a different, fast-rising threat: gonorrhoea. As sexually transmitted infections reach alarming levels and treatment options shrink due to antibiotic resistance, the MenB vaccine is revealing a surprising, secondary benefit that could shift how public health systems tackle STI control.
Recent studies have uncovered that this vaccine, originally designed to fight Neisseria meningitidis, offers partial protection against Neisseria gonorrhoeae, the bacterium responsible for gonorrhoea. While this cross-protection is unintentional, it has sparked significant interest across public health and scientific communities. The implications are profound — particularly in a country where gonorrhoea is making an aggressive resurgence.
This article explores the science behind the MenB vaccine, the data supporting its unexpected efficacy against gonorrhoea, and what this means for patients, parents, and public health policy in the United Kingdom.
Understanding the MenB Vaccine: From Meningitis to Wider Protection
What Is MenB and How Is It Used?
Developed by GlaxoSmithKline, Bexsero is the only licensed MenB vaccine in the UK and is primarily designed to prevent meningococcal group B disease — a potentially life-threatening illness that causes meningitis and blood poisoning. Since 2015, it has formed a routine part of the NHS childhood vaccination schedule, given to babies at 8 weeks, 16 weeks, and again at one year as a booster dose.
Administered via intramuscular injection, the vaccine commonly causes mild side effects such as fever or soreness at the injection site. To reduce discomfort and fever in infants, paracetamol is usually recommended after the first and second doses.
Beyond its use in babies, the vaccine is also available for:
- Individuals over the age of two with underlying conditions (e.g. asplenia or complement disorders)
- Laboratory staff working with Neisseria meningitidis
- Certain high-risk groups are eligible for free NHS vaccination
This wide availability and robust distribution infrastructure have allowed the vaccine to become one of the UK’s most established public health tools.
The Genetic Overlap That Sparked a Discovery
The unexpected link between the MenB vaccine and gonorrhoea protection lies in the biological similarity between the two bacteria. N. meningitidis and N. gonorrhoeae share around 80 to 90 per cent of their genetic material. This overlap includes several key proteins and outer membrane vesicles (OMVs), which the vaccine targets to create an immune response.
As a result, the antibodies triggered by the MenB vaccine, particularly those that target conserved components like lipooligosaccharide (LOS) — may also offer a degree of cross-reactive immunity against gonorrhoea. In effect, the body is prepared to recognise and defend against elements of both bacteria.
How MenB Offers Partial Protection Against Gonorrhoea
What the Research Shows
A growing body of evidence supports this unexpected benefit. Systematic reviews and meta-analyses have found that receiving at least one dose of the MenB vaccine can reduce the risk of contracting gonorrhoea by around 32 per cent. The effectiveness appears to increase with the second dose, ranging from 33 to 40 per cent protection.
| Vaccine Doses | Individual Study Range | Pooled Effectiveness | Study Type |
| ≥1 dose | 23% – 47% | 32.4% | Retrospective cohort, case-control |
| 2 doses | 33% – 40% | Included above | Retrospective cohort |
While this level of protection may not seem high at first glance, it is important to recognise its significance on a population level. Even moderate protection can lead to substantial public health gains when applied across a wide demographic — such as a national infant population or a high-risk adult group.
Professor Andrew Pollard, Chair of the Joint Committee on Vaccination and Immunisation (JCVI), has emphasised that this level of effectiveness is “worth having“, particularly given the mounting pressure of resistant gonorrhoea.
The Science Behind the Shield
The mechanism of protection centres on bactericidal antibodies — specifically, IgG antibodies that latch onto conserved structures on the gonorrhoea bacterium. While the MenB vaccine does not contain every antigen shared with gonorrhoea, it includes several with close equivalents. For example:
- NHBA (Neisserial Heparin Binding Antigen) is around 70% conserved in N. gonorrhoeae
- FHbp (Factor H binding protein), although more variant, may still contribute
These overlapping targets allow the immune system to mount a partial defence against gonorrhoea following MenB vaccination, even though the vaccine was never intended for that purpose.
Public Health Impact: Why This Matters More Than Ever
Alarming Trends in Gonorrhoea Rates
The timing of this discovery could not be more urgent. Gonorrhoea rates in the UK are rising at an unprecedented pace. In 2023 alone, England recorded 85,223 diagnoses — the highest since records began, with the UK Health Security Agency (UKHSA) describing the trend as “increasing and getting worse“.
| Year | Diagnoses | Change from Previous Year |
| 2021 | 54,961 | – |
| 2022 | 82,592 | +50.3% |
| 2023 | 85,223 | +3.2% |
The steepest increases have been observed in young adults, particularly those aged 15 to 24. Among 19- and 20-year-olds, rates surged by 229 percent in just over a year.
A Crisis Compounded by Resistance
Alongside this explosion in cases is a worrying rise in antibiotic-resistant strains of gonorrhoea. The front-line treatment, ceftriaxone, is becoming less effective. Since 2015, at least 42 cases of ceftriaxone-resistant gonorrhoea have been reported in England. Even more troubling, 15 of these were extensively drug-resistant (XDR) — resistant to multiple treatments.
In just over a year (January 2024 to March 2025), 17 new cases of ceftriaxone-resistant gonorrhoea were identified, nearly matching the total from the previous two years combined.
Dr Katy Sinka, Head of the STI section at UKHSA, has cautioned that gonorrhoea is approaching a point where it could become “untreatable“.
This makes even partial vaccine protection highly valuable. It provides an added barrier to infection, reduces transmission potential, and buys time for health systems grappling with dwindling treatment options.
A 2023 modelling study by Imperial College London estimated that high uptake of the MenB vaccine among at-risk groups could prevent over 100,000 cases of gonorrhoea in the next ten years, saving the NHS £7.9 million in treatment costs. These figures are not just theoretical; they highlight how repurposing existing vaccines can bring tangible benefits, even without perfect immunity.
The NHS Response: Turning Evidence into Action
How the MenB Vaccine Is Being Used Today
The MenB vaccine has long been a fixture in the UK’s immunisation schedule for infants. It’s administered at 8 weeks, 16 weeks, and again at one year, offering essential protection against meningococcal group B disease. It is also provided to high-risk individuals such as:
- Those with asplenia or splenic dysfunction
- Individuals with complement deficiencies
- Laboratory professionals handling Neisseria meningitidis
This targeted use has recently been expanded. In November 2023, the Joint Committee on Vaccination and Immunisation (JCVI) recommended a focused rollout of the MenB vaccine for gonorrhoea prevention, marking the first time any country has used a meningitis vaccine in this way.
Starting in August 2024, local authority-commissioned sexual health clinics began inviting eligible individuals for vaccination. The primary group targeted includes gay and bisexual men who have multiple recent sexual partners or a prior history of sexually transmitted infections. This reflects a high-incidence demographic with a disproportionate disease burden.
A Broader Approach to STI Prevention
The rollout is more than just a one-off jab. Attendees are also offered vaccinations for:
- Mpox (formerly monkeypox)
- Hepatitis A and B
- HPV (human papillomavirus)
This integrated model streamlines delivery, increases efficiency, and enhances overall vaccine uptake. For patients, it means fewer appointments, more protection, and easier access to essential care.
By repurposing an existing, thoroughly tested vaccine, the NHS can act swiftly, using real-world evidence to mitigate an emerging crisis without waiting for the lengthy development of a gonorrhoea-specific vaccine. It’s a pragmatic, cost-effective strategy that makes the most of existing infrastructure.
Limitations and Necessary Cautions
Partial Protection, Not a Substitute
Despite the promising data, it is crucial to underscore the limitations of the MenB vaccine’s effect on gonorrhoea. This is not a dedicated gonorrhoea vaccine, and its protection is incomplete. Studies show that effectiveness ranges from 23% to 47% for one dose, and 33% to 40% for two doses.
This means vaccinated individuals can still become infected and transmit the disease. As such, the MenB vaccine should not be viewed as a replacement for standard STI prevention methods. It is an additional layer of protection, not a standalone solution.
Public Messaging Must Be Clear
There is a delicate balance in public communication. While it’s important to highlight the benefit of the vaccine, doing so without care may lead some to falsely believe they no longer need to practise safe sex or seek regular STI testing.
Health authorities have consistently maintained that:
- Condom use with new or casual partners remains the most effective preventive method
- Regular STI screening is essential, especially since many gonorrhoea cases are asymptomatic
- Early treatment remains key to preventing complications such as pelvic inflammatory disease (PID) or infertility
Any messaging around the MenB vaccine must reinforce these principles, avoiding complacency while encouraging participation in vaccination programmes.
Future Outlook: A New Vaccine Frontier
From Repurposing to Innovation
Encouraged by these findings, researchers and pharmaceutical companies are now racing to develop vaccines specifically targeting gonorrhoea.
GlaxoSmithKline (GSK), the developer of Bexsero, is leading a Phase II clinical trial for a Neisseria gonorrhoeae vaccine candidate. The vaccine, dubbed NgG, has already received Fast Track designation from the US Food and Drug Administration (FDA), expediting its development due to the urgent medical need.
Other players in this space include:
- Intravacc: working on OMV-based formulations with tailored gonorrhoeal antigens
- LimmaTech Biologics and UMass Chan Medical School: investigating subunit protein approaches
- Evaxion: developing an mRNA-based candidate, inspired by the COVID-19 vaccine model
This flurry of research reflects the growing realisation that vaccines will be a critical pillar in controlling STIs, particularly in the face of rising drug resistance.
Global Recognition and Support
The World Health Organization (WHO) has classified Neisseria gonorrhoeae as a “high-priority” pathogen due to its increasing antibiotic resistance. The WHO’s Global Health Sector Strategy on STIs aims to reduce gonorrhoea incidence by 90% by 2030, with vaccine development identified as a key strategic component.
Vaccines are now seen not only as tools to prevent specific infections but also as crucial assets in the wider fight against antimicrobial resistance (AMR). By reducing infection rates, they also reduce the use — and misuse — of antibiotics, slowing the pace at which resistance develops.
What This Means for Patients and Parents
An Added Layer of Protection
For the many children already vaccinated with MenB through the NHS, this unforeseen benefit may provide secondary protection as they reach sexual maturity. While the protection is partial, it contributes to reduced susceptibility at a population level.
Parents can take comfort in knowing that a vaccine already safeguarding their child from meningitis might also help shield them from a sexually transmitted infection later in life. This added dimension reinforces the importance of adhering to the recommended NHS vaccination schedule.
Continued Vigilance Still Required
However, this benefit must not lead to a false sense of security. The vaccine is not a green light to disregard other STI prevention measures. For sexually active individuals, especially young adults, the combination of vaccination, regular testing, and safe sex practices offers the most effective protection.
Access to STI testing in the UK is:
- Free and confidential
- Available via local clinics, university health services, or at-home kits
- Supported by NHS-backed digital tools for ease of access and discretion
Public health campaigns must continue to emphasise this layered approach, where medical innovation is paired with individual responsibility.
Final Thoughts: Reframing STI Prevention in the UK
The unexpected cross-protection offered by the MenB vaccine represents a remarkable twist in the UK’s effort to curb the spread of gonorrhoea. In an age where antibiotic resistance is reshaping how infections are managed, this discovery offers a glimmer of progress — not just medically, but strategically.
The NHS has responded swiftly, implementing a world-first vaccination programme for at-risk populations. Meanwhile, international research into dedicated gonorrhoea vaccines continues at pace. The lesson here is that existing tools can be repurposed with vision and that innovation often comes from unexpected findings.
This is a reminder for patients, parents, and public health professionals that science does not move in straight lines. It advances through connections, often unanticipated, but full of potential.
The MenB vaccine’s broader impact illustrates the future of public health: one where cross-sector collaboration, strategic repurposing, and evidence-led policies work together to stay ahead of the disease.
