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In this interview we discuss the recent Meningitis B outbreak with experts Professor Mariagrazia Pizza, Chair in Microbiology and Professor Shiranee Sriskandan, Professor of Infectious Diseases.

In March 2026, a serious outbreak of Meningitis B was confirmed in Kent, UK. A number of university and college-aged ÌìÃÀ´«Ã½ were confirmed to have been infected and sadly, two people died. The cases were centred around one nightclub and triggered a rapid public health response from public health teams, with contact tracing, antibiotics and vaccination all utilised to stem the outbreak.

Meningococcal meningitis is caused by the bacterium called Neisseria meningitidis, with five serogroups (A, B, C, W, and Y) responsible for the majority of cases. Not all bacterial meningitis is caused by Neisseria meningitidis B which was found in Kent. Importantly, bacterial meningitis is more serious than viral meningitis;   It is rare to be infected with invasive Meningococcal B,

What can we learn about the recent outbreak of Meningitis B in Kent, and what do we need to know about this particular strain? We spoke to from the Department of Infectious Disease and from the Department of Life Sciences about the March outbreak. Professor Pizza had a central role in the development of the vaccine that is now routinely administered to all newborns to prevent Meningitis B, while Professor Sriskandan is a clinical infectious diseases physician. Both researchers are also Co-directors of the Centre of Bacterial Resistance Biology at Imperial.

What happened in the recent meningitis outbreak, and how concerned should the public be?

Shiranee Sriskandan: In the outbreak in Kent, over 20 sixth-form and university-aged young people contracted invasive* meningococcal disease and developed meningitis; sadly, two died. This happened within a very short time, and when public health experts looked at the epidemiology, even before laboratory confirmation of some of the cases, it became clear that they all had an association with one club, consistent with an outbreak that had a common source.

Meningitis B is a disease that has a high mortality, even in otherwise healthy young people, of around 8% normally, but it is not an infection we see very commonly now - it’s rare. For that reason, there is no reason for the wider public to be unduly alarmed. It was really just linked to one area. There have also been other smaller outbreaks in and , again associated with young people since the Kent outbreak, but none of those outbreaks has been connected to the outbreak in Kent.

*Invasive meningitis B: This is when pathogens like the meningitis B bacterium (Neisseria meningitidis serogroup B) move beyond just living in the throat or nose and ‘invade’ the body’s bloodstream (‘bacteraemia’ or ‘septicaemia’), as well as the lining of the brain and spinal cord (‘meningitis’). If this happens, the condition is life-threatening.

Meningitis B is a disease that has a high mortality, even in otherwise healthy young people, of around 8% normally, but it is not an infection we see very commonly now - it’s rare. Professor Shiranee Sriskandan Department of Infectious Disease

Shiranee Sriskandan: We’ve always seen outbreaks in college-aged ÌìÃÀ´«Ã½, which was one of the reasons why the Meningococcal ACWY vaccine was introduced for teenagers in the UK, although this was to protect them from serogroups A, C, W and Y of N. meningitidis and not against serogroup B. The outbreaks we’ve seen in the past involve maybe two to three cases at most. What was exceptional here was the number of definite or highly probable cases, which was extremely high. Other countries have had outbreaks of up to eight or nine cases linked to discos or clubs,

Studies from the 1990s showed increased carriage* during freshers’ week, which was associated with smoking, crowded settings, and close contact. The ‘MenC’ vaccine was introduced in the 1990’s, which led to a fall in MenC cases, and this was upgraded to the MenACWY vaccine in 2015.  This means that MenB is the remaining main cause of invasive meningococcal disease that we see now.  A vaccine for MenB had always seemed elusive, but the work of scientists like Mariagrazia made it a reality, and from 2015, the UK started to vaccinate babies against MenB. 

*Carriage: This refers to the percentage of people who carry a pathogen without symptoms. This is usually on the person’s mucous membranes, such as in the nose. 

Mariagrazia Pizza: Most outbreaks occur in colleges. Adolescents are more vulnerable because antibody levels decline at that age, and they also have closer social contact with each other. Outbreaks in different countries, including the US, France, the UK, and Italy, are always caused by different strains. About 10% of the population can carry meningococcus in the nose without getting the disease. In situations where many people are close together, kissing or drinking together, the risk of serious infection increases.

What factors contributed to this specific outbreak?

Shiranee Sriskandan: Every outbreak involves environmental factors, pathogen factors, and host factors.  In terms of environmental factors, in this case, maybe close contact, smoking or vaping, possibly humidity and survival of bacteria in aerosols affected carriage rates- if more people are carrying it, inevitably more people will get the more serious form of invasive disease.

Then there is the biology of the pathogen itself. We know for other bacteria, like group A Streptococcus, some strains are inherently more invasive than others - experts on N. meningitidis are now looking to see if there is anything unusual about the strain that was circulating in Kent.

The strain which was identified has been circulating since 2020 in the UK. There are some genomic differences, but we don’t yet know if this explains the higher spread. Professor Mariagrazia Pizza Department of Life Sciences

Then there is the host and the very important immune response - apart from the fact that the MenB vaccine currently is not routinely given to babies and not to other children or young people, there was the added factor that during the pandemic we saw almost no meningococcal disease, or indeed many infections transmitted from the nose and throat - linked to the restrictions on social gatherings. The reduced exposure to N. meningitidis likely led to reduced herd immunity to this pathogen, particularly among teenagers and young people, where the MenACWY vaccine had already reduced carriage and circulation of Neisseria strains. The problem is that even if vaccinated, the MenACWY vaccine offers no protection against MenB. So, you might predict that there would be a so-called 'immunity gap’ in this population that paradoxically makes them more prone to invasive MenB if they encounter this.

To tackle this, for ÌìÃÀ´«Ã½ in Year 13 and those heading to university or further education for the first time this Autumn. We hope to see this reduce the gap and protect the age groups who are at the highest risk.

Mariagrazia Pizza: The fatality rate during the Kent outbreak was identical to the UK case fatality rate for invasive Men B in 2025, so the strain itself does not seem more virulent. The difference was how many people were infected. We don’t know the carriage rate because only symptomatic people were monitored in this outbreak.

But the strain which was identified has been circulating since 2020 in the UK. There are some genomic differences, but we don’t yet know if this explains the higher spread.

What are the symptoms to look out for, and why is meningitis sometimes caught late?

Shiranee Sriskandan: This disease progresses very rapidly. Even when clinicians recognise it, patients may still unfortunately die. Key symptoms include high fever, feeling profoundly unwell, low blood pressure, muscle aches, and sometimes a rash. The meningococcal rash does not blanche*, but it’s often a very late feature.

If the patient has meningitis, there will be headache, stiff neck, and light sensitivity which can make diagnosis easier. Often, invasive meningococcal disease can start off looking like ‘flu, making it much harder to spot, and that is where delays can happen.

*Meningitis rash: This is red or purple markings on the body which remain present when pressed with a glass. However, the rash does not always appear in cases.

We saw antibiotics and vaccines used during this outbreak. Is that the standard response?

Shiranee Sriskandan: . One case of bacterial meningitis triggers prophylaxis* for the household. Multiple cases trigger wider prophylaxis depending on the setting; there is even a guideline for colleges and schools. Antibiotic effects are immediate in terms of clearing carriage, but vaccines can be useful once the strain type is known to protect against invasive infection.

*Prophylaxis: This is a treatment course (often medication) which is used to prevent a disease or infection. During this outbreak, many people were given antibiotic prophylaxis to use to reduce carriage and prevent infection.

Mariagrazia Pizza: In adolescents, vaccine-induced immunity develops quickly within 7 to 10 days. One dose provides some protection, but two doses are needed for longer-term immunity, which is why the new vaccine programme of two doses is very important. 

Depending on the bacterial strain causing the outbreak and how well the vaccine matches the outbreak strain, vaccines can be highly effective in reducing the severity of infection.

Mariagrazia, you led the discovery of the Meningitis B vaccine. Could you tell us more about how a New Zealand outbreak fuelled this discovery?

Mariagrazia Pizza: Tailor-made vaccines based on outer membrane vesicles had already been developed specifically for outbreaks of Meningitis B, which had proved effective in Cuba and Brazil.  An outbreak in New Zealand happened in 1991, and there was a very high incidence of this disease, so it became an epidemic until the mid 2000s. The epidemic was driven by a strain of Neisseria meningitidis serogroup B, and because it had lasted many years, the New Zealand Ministry of Health looked for companies to work together to develop a vaccine. A collaboration between the NZ Ministry of Health, the Norwegian Institute of Public Health (NIPH) and Chiron Vaccines (now Novartis/GSK), where I worked, was established to develop a vaccine specifically targeting the New Zealand outbreak strain, which was then produced by Chiron.

It takes time to develop a vaccine, and it took over two years to develop MenNZB and roll it out for use. All the population of New Zealand from five weeks up to 18 years of age were then vaccinated.

The issue with a Meningitis B vaccine is that, unlike other vaccines, such as those in meningococcal C strains, which are polysaccharide-based and target the bacterial capsule, allowing coverage of all the Men C strains, the meningococcus B vaccine is protein-based. These proteins can vary between strains, making broad coverage more difficult.

Unlike other vaccines, such as those in meningococcal C strains, which are polysaccharide-based and target the bacterial capsule, allowing coverage of all the Men C strains, the meningococcus B vaccine is protein-based. Professor Mariagrazia Pizza Department of Life Sciences

The current Meningitis B vaccine (Bexsero) has been designed, however, to cover many strains. So, genetic variation does exist but develops more slowly than for something like influenza, which requires vaccine updates every year. For now, coverage is acceptable, and vaccines don’t yet need frequent updating.

Shiranee Sriskandan:  With other types of Neisseria, they have got a polysaccharide capsule that we can target and vaccinate against, but the Meningitis B capsule is too similar to something in our own bodies, so we can’t use it as a target. The only option is to use other components of the surface of the bacteria.

Mariagrazia Pizza: Another interesting observation was a reduction in the incidence of gonorrhoea cases, caused by the bacterium Neisseria gonorrhoeae, after the introduction of the MenB vaccine. Meningococcus and Gonococcus are two completely different bacteria - one causes meningitis, and the other causes gonorrhoea - but they come from the same bacterial genus, with up to 90% identity at genome level.

Through a retrospective analysis, scientists in New Zealand found that after vaccination with OMV vaccine, there was a 31% decrease in gonorrhoea cases.  This led to the hypothesis that vaccination against Meningitis B could also provide partial protection against gonorrhoea. Subsequent studies in other countries have reported similar findings. As a result, the Bexsero vaccine has also been introduced in the UK for high-risk populations to prevent gonorrhoea.

Since gonorrhoea strains are now showing high antibiotic resistance and we only have a few antibiotic combinations that work, the hope for the future to reduce gonorrhoea infection would be vaccination.

What would you like to see next for meningitis vaccines?

Mariagrazia Pizza: The WHO initiative for a is the long-term goal. Combination vaccines are being developed, but none cover all serogroups globally. Higher vaccination coverage could reduce transmission overall.

What is the key takeaway from this outbreak for you personally?

The key clinical lesson for us is the importance of notification on suspicion of the disease based on a syndrome. Professor Shiranee Sriskandan Department of Infectious Disease

Shiranee Sriskandan: From a clinical side, the public health response was very good and very fast. The key clinical lesson for us is the importance of notification on suspicion of the disease based on a syndrome. Waiting for microbiological confirmation is dangerous, and often in the case of meningitis, patients may have received antibiotics already, meaning we will never grow the bacterium. This outbreak shows why early notification matters. Although it seems there has been a flurry of outbreaks, we need to remember we normally see around 300 cases of meningococcal disease per year; I do think the immunity gap may be affecting the tendency to outbreaks, though and hopefully the new programme will help to address this.

Mariagrazia Pizza: For me, it is painful that adolescents died when a vaccine exists. We know outbreaks happen in colleges, and carriage increases when ÌìÃÀ´«Ã½ enter university. These are known factors, and we should reflect on them.

Another lesson is public panic - when vaccine supplies are limited, people rush to get protected. When something happens, you realise much could have been avoided.