DNA analysis has given scientists new clues about why an unusual strain of meningitis B caused such serious illness among young people, the BBC has found.
An unusually aggressive strain of meningitis B may have helped turn a night out in Canterbury into the centre of one of the UK’s most serious meningitis outbreaks in recent years.
More than 20 young people, many of them students, became infected after an outbreak linked to a Canterbury nightclub in March. Every patient needed hospital treatment, nine were taken into intensive care and two people died.
Now, scientists believe they have found an important clue to why the infections were so severe.
Researchers from the UK Health Security Agency (UKHSA) and the University of Oxford examined the genetic makeup of the bacteria responsible. Their analysis suggests the meningitis bacteria had acquired DNA from other bacteria that can naturally live in the human throat.
The process is called horizontal gene transfer. Rather than simply passing genetic information from one generation to the next, bacteria can sometimes acquire genetic material from other bacteria. Scientists say this can result in significant changes to how an infection behaves.
Dr Charlene Rodrigues, a UKHSA consultant in pathogen genomics, said the findings demonstrate how rapidly bacteria can change.
The genetic changes may have helped the outbreak strain cause more serious illness, while also making it less familiar to people’s immune systems.
But genetics was only part of the story. The outbreak is thought to have begun when someone carrying the bacteria entered a nightclub where large numbers of young people were in close contact. Meningitis-causing bacteria can spread through activities such as kissing or sharing drinks and vapes.
The outbreak’s rapid rise was followed by an equally striking decline. Scientists believe the characteristics that made the strain more dangerous may have limited its ability to circulate for a long time. People who became severely ill were less likely to unknowingly carry and transmit the bacteria.
Prof Robert Heyderman, an infectious diseases expert at University College London, said the strain may actually have been circulating among healthy people before the conditions allowed the outbreak to take hold.
Although meningitis outbreaks can occur, the speed and concentration of cases in Kent were considered highly unusual.
In response, health officials introduced a one-off MenB vaccination programme for young people heading to university. First doses are available until 31 December 2026, with second doses available until 31 March 2027.
Meningitis can develop quickly. Warning signs include a severe headache, fever, vomiting, stiff neck, sensitivity to light, drowsiness, seizures and a rash that does not fade when pressed.
Not everyone will develop every symptom, and they can appear in any order. Because bacterial meningitis can become life-threatening within hours, anyone who develops symptoms and becomes seriously unwell should seek urgent medical attention.
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