Causes of meningitis, what the public health response has been, and how the situation differs from Covid
The meningitis outbreak in Kent has raised concerns about the potential spread of the disease, prompting a resurgence of mask-wearing and vaccination queues. Although these scenes may evoke memories of the Covid crisis, meningitis is fundamentally different. This article examines how the outbreak has developed.
What is meningitis?
Meningitis is a potentially fatal but rare disease caused by viruses and bacteria that lead to inflammation of the meninges, the protective membranes covering the brain. The current outbreak in Kent is caused by meningococcal bacteria, which reside in the nose and throat of approximately 10% of the population. Multiple strains of meningococcal bacteria exist, including MenA, MenB, MenC, MenW, MenX, and MenY. The strain responsible for the Kent outbreak is MenB. These bacteria have coexisted with humans for centuries, and public health authorities have extensive experience managing the disease.
“With this particular organism, we’ve got several hundred years of history now, and we can absolutely predict what factors are likely to have played into the outbreak,” said Prof Sir Andrew Pollard at the University of Oxford, the director of the Oxford Vaccine Group.
The Covid pandemic was markedly different, caused by a novel, highly transmissible airborne virus that public health officials had to understand rapidly. No country had prior experience with Covid, and no one had pre-existing immunity.
Who is at risk?
Meningitis is more prevalent among babies, teenagers, and young adults compared to other age groups. Babies are particularly vulnerable due to their immature immune systems. Teenagers and young adults face higher exposure to the bacteria, primarily because of their living environments and social behaviors. Among student populations, about 25% carry the bacteria and can potentially transmit it.
How does bacterial meningitis spread?
Meningococcal bacteria spread through close and prolonged contact, such as living in the same household or student accommodation, intimate contact like kissing, or sharing drinks or vaping devices. Individuals who carry the bacteria often do not exhibit symptoms, and only a minority of those infected develop meningitis.
The bacteria spread much less easily than coronavirus. Covid patients can expel large amounts of virus particles into the air through coughing and sneezing, whereas meningococcal bacteria survive poorly outside saliva droplets or respiratory secretions and quickly settle to the ground if airborne.
“It’s much harder to pick up, because it’s just not around in the environment in the same way,” said Dr Eliza Gil, a clinical lecturer at the London School of Hygiene & Tropical Medicine.
How fast does it spread?
The Covid pandemic familiarized the public with R values, which indicate the average number of people an infected individual transmits the disease to. An R above one signals rising cases, while below one indicates a decline. Early in the Covid pandemic, the R value was around three but decreased with social distancing, lockdowns, and vaccinations. Due to insufficient cases, a reliable R value cannot be calculated for the Kent meningitis outbreak. However, meningitis spreads far less effectively than Covid or influenza, and the widespread use of antibiotics and vaccines is expected to help contain the outbreak.
How common is meningitis?
Meningitis was more common in the past. In the 1990s, England recorded over 2,000 cases annually, primarily caused by MenC bacteria. Cases declined sharply after 1999 following the introduction of the MenC vaccine and later expansion of vaccines to cover MenA, C, W, and Y strains. Since 2015, the NHS has offered the MenB vaccine to babies, which protects them during the vulnerable first year but is expected to wane by adolescence. Individuals vaccinated as infants are unlikely to retain protection in their late teens.
During the pandemic, meningitis cases dropped below 100 in 2020-21 but have since rebounded, reaching 378 cases in 2024-25. Other infections such as influenza, respiratory syncytial virus (RSV), whooping cough, and gonorrhea have shown similar rebounds, partly due to reduced immunity from pandemic-related social restrictions.
On average, public health officials in England expect about one meningitis case daily. It is important to differentiate these from cases linked to the Kent outbreak.
Why do some people get severely ill?
Severe illness occurs when bacteria enter the bloodstream, reach the fluid-filled spaces around the brain, and multiply. The reasons why some individuals develop severe disease while others do not remain unclear, but bacterial strain and host immunity play significant roles.
“We often see cases in the first year or two after people go to university,” Pollard said. “They bring the strains from their home town, and come together in a central place where the strains start mixing. Eventually they find someone who is not only susceptible to carrying it, but who actually then develops severe disease because they are susceptible, and that is around their background immunity.”
Historically, hyper-invasive meningococcal strains emerge and recede. A strain may cause serious disease for about a decade before declining as immunity develops, only to reappear decades later. The MenB strain causing the Kent outbreak has circulated in the UK for approximately five years.
What sparked the Kent outbreak?
The outbreak has been traced to Club Chemistry in Canterbury. This is not the first meningitis outbreak linked to a nightclub. In October 1997, three students at Southampton University died of meningitis after attending the same venue. Australia has also reported cases linked to nightclubs. Such venues facilitate infection spread. A study of British teenagers found that attending pubs and clubs, kissing, and smoking together increased the risk of meningococcal infection fourfold.
Dr Gil suspects the outbreak was triggered by a superspreader who shed a large amount of MenB bacteria. Those infected may have been more susceptible due to recent respiratory infections or smoking and vaping, which can facilitate bacterial adhesion to airway tissues. As of Friday, 18 cases were confirmed and 11 were under investigation, with two deaths reported.
Pollard said: “It’s some sort of perfect storm of the particular organism, the hosts’ immunity and the event. I’m sure they will be looking at what’s happened that might have made it more likely to spread.”
How is the outbreak being contained?
The public health response follows established protocols. Individuals diagnosed with meningitis are typically hospitalized. Those at risk, including attendees of the same nightclub, are offered antibiotics and the Bexsero MenB vaccine. Antibiotics aim to eliminate the bacteria from the nose and throat before severe illness develops or transmission occurs. The MenB vaccine protects against meningitis if infection occurs in the following weeks but does not prevent bacterial carriage in the nose and throat, so transmission can still occur. The vaccine is administered in two doses one month apart, with protection peaking approximately five weeks after the first dose.
