British health authorities confirmed Friday that the Bexsero vaccine is effective against the strain of meningococcal bacteria behind a fast-moving outbreak in southeast England that has killed two people and sickened dozens.
The U.K. Health Security Agency (UKHSA) said early laboratory analysis identified the infections as ST-41/44, a strain of group B meningococcal bacteria that has circulated in the U.K. in recent years.
While the confirmation provides “important reassurance,” UKHSA warned that investigations and monitoring are ongoing.
Authorities have now administered 2,360 vaccinations and distributed roughly 9,840 courses of antibiotics.
As of Thursday evening, 18 cases were confirmed, with 11 others still under investigation. Clinics expanded rapidly on Thursday in response to growing concern, though officials emphasized the outbreak had not yet been contained.
For context, the U.K. typically sees only about one case of invasive meningitis per day, underscoring the unusual speed and scope of this outbreak.
The epicenter is believed to be Club Chemistry in Canterbury, Kent, where at least 10 of the confirmed cases had attended between March 5-7, according to Health Secretary Wes Streeting.
In total, 27 cases are currently being probed, with 15 confirmed. Most of those affected are University of Kent students, but cases have also been reported at four local schools and a higher education institution in London.
Two deaths have been recorded: a 21-year-old university student and a sixth-form pupil.
Meningitis is a potentially life-threatening infection that inflames the protective membranes surrounding the brain and spinal cord, and can progress rapidly to sepsis.
Early symptoms, such as fever, headache, drowsiness, stiff neck, vomiting, shivering, cold extremities, and sometimes a distinctive rash, often mimic other illnesses, delaying diagnosis.
Transmission requires prolonged close contact, such as kissing or sharing drinks, making outbreaks in social settings like nightclubs particularly dangerous, said Andrew Lee, Professor of Public Health at the University of Sheffield.
Experts describe the outbreak as “unprecedented” due to its speed and intensity. UKHSA chief Susan Hopkins said, “In my 35 years working in healthcare, this is the most cases I’ve seen in a single weekend from this type of infection. This appears to be a superspreader event, with continued transmission in student residences.”
U.K. authorities have launched an aggressive contact tracing and response effort.
Health clinics in Canterbury are distributing antibiotics to close contacts, while the University of Kent has rolled out a targeted MenB vaccination program, offering 5,000 jabs to students.
Although MenB vaccination has been part of the U.K.’s immunization schedule since 2015, demand nationwide has outpaced supply, with pharmacy chain Boots reporting limited availability.
Prime Minister Keir Starmer urged anyone who attended the nightclub over the outbreak weekend to seek antibiotics immediately.
Globally, meningococcal disease infects more than two million people each year, with the majority in developing countries.
In the U.K., group B meningococcal disease is the most common strain. The bacteria can reside harmlessly in the throats of 10%-24% of the population, making asymptomatic carriers a key factor in the spread of outbreaks.
Health officials caution that while the outbreak is serious, the risk to the general public remains low. Bacterial meningitis requires urgent hospital treatment. Laboratory analyses continue to investigate why this strain has been unusually aggressive, and authorities warn that the number of cases could rise further.
