Gonorrhoea is a sexually transmitted infection that can infect both men and women. It can cause infections in the genitals, rectum, and throat. It is a very common infection, especially among young people aged 18-25 years.

Meningococcal disease and gonorrhoea are caused by bacteria that are closely related but cause different diseases that are spread in different ways. New evidence suggests that the Meningococcal B vaccine (Bexsero®) licensed outside of Kenya against meningococcal B disease may also be effective against gonorrhoea due to genetic similarities between the two organisms causing the two diseases. The aim of this study is to generate data to develop a gonorrhoea vaccine, using an existing vaccine against meningococcal disease

Meningococcal disease and gonorrhoea are caused by bacteria that are closely related but cause different diseases that are spread in different ways. New evidence suggests that the Meningococcal B vaccine (Bexsero®) licensed outside of Kenya against meningococcal B disease may also be effective against gonorrhoea due to genetic similarities between the two organisms causing the two diseases. Investigators will conduct a clinical trial of the Meningococcal B vaccine (Bexsero®) in approximately 50 male and female participants aged 18-25 years who are in follow up in KEMRI cohorts (including HIV-uninfected and infected individuals) at the KEMRI clinic in Mtwapa. This is not an efficacy trial. Instead, investigators will assess if immunisation of individuals at risk for gonococcal infection with 4CMenB (Bexsero®) elicits humoral and T cell cross-reactive responses against Neisseria gonorrhoeae (Ng). Participants will make six study visits, including a screening visit, an enrolment visit and 4 follow up visits. InvestigatorsF will offer vaccination with the Meningococcal B vaccine (Bexsero®) vaccine at the enrolment visit and approximately 2 months later. Investigators will collect a 20ml blood sample at enrolment, and following the first vaccination, and a 70ml blood sample following the second vaccination. At study completion (month 6), investigators will collect a 4ml blood sample. Investigators will collect a throat swab, a urine sample (for men), vaginal swab, and an anal swab at the enrolment, month 3 and month 6 visit to test for Chlamydiae and Gonorrhoea infection. Total study participation for participants is 6 months. Upon study completion, participants will continue to receive research care at the KEMRI clinic in Mtwapa.

Inclusion Criteria:

• Healthy male and female as assessed by a medical history, physical exam, and laboratory tests (specified in study operations manual).
• At least 18 years of age on the day of screening and will not reach 26th birthday on the day of the second vaccination (approximately 6 weeks after enrolment)
• Willing and able to give informed consent for participation in the trial before any study-related procedures are performed.
• Willing to donate blood samples for immunogenicity assessments.

Exclusion Criteria:

Any clinically significant acute or chronic medical condition that is considered progressive that, in the opinion of the Principal Investigator or designee, makes the volunteer unsuitable for participation in the trial

• Pregnancy
• Participation in another clinical trial (i.e. investigational HIV vaccine candidate), within the previous 3 months or expected participation during the study
• Bleeding disorder diagnosed by a physician (e.g., factor deficiency, coagulopathy or platelet disorder that requires special precautions).
• History of severe local or systemic reactogenicity to vaccines (e.g., anaphylaxis, respiratory difficulty, angioedema).

All trial data will be entered in the clinical trial database, which are maintained through Standard Operating Procedures.

The volunteer will be identified by a unique trial specific number and/or code in any database. The name and any other identifying detail will NOT be included in any trial data electronic file.

during study and storage for 10 years

Direct access will be granted to authorised representatives from the Sponsor, host institution and the regulatory authorities to permit trial-related monitoring, audits and inspections.