Why has this outbreak of meningitis spread so quickly?

 

This meningitis outbreak deeply unusual and defies easy explanation(Image: Getty Images)

This meningitis outbreak is deeply unusual and defies easy explanation.

 Since the weekend, there have been 20 cases in a small part of Kent, which has been called unprecedented and explosive. This is not the normal pattern.

 Meningitis typically manifests as one-off, isolated cases. It is now uncommon in the UK, but there are occasionally small clusters, like the 2023 case of two infants at a nursery in the north of England. There have been outbreaks of a greater scale before. In the 1980s, there were 65 cases of MenB, including two deaths, in Gloucestershire but those cases were reported over four- and-a-half years not less than a week.

 The pressing concern is: what has changed this time? How has an infection that requires close and prolonged physical contact, that spreads more slowly than measles, Covid or flu, caused such a rapid outbreak?

Read More: 

What are the symptoms of meningitis and how is it spread?

It currently appears to be an exceptional outbreak in circumstances that appear to be unexceptional, so the answer is important but not immediately apparent. Even connections to the Club Chemistry nightclub, where 11 of the first 15 people who were affected had partyed, are not enough to provide a complete picture. Instead of being a one-of-a-kind event, students sharing drinks and vapes in a crowded nightclub is a scene that happens all over the country. We are aware that the meningitis B bacteria infect people frequently and typically reside harmlessly in the nose. These bugs affect about 10% of people in the UK, but 25% of teenagers and young adults do. It's only in a tiny number of cases that the bacteria cross the barriers inside our nose to invade the body and cause meningitis and sepsis.

 For Prof Andrew Preston, from the University of Bath, there are two broad explanations for the numbers getting severely ill and dying in Kent.

 He informed me that either the infection is proving to be "more invasive" this time around or there has been an "astonishing rate of transmission," indicating that so many more people are contracting the bacteria. The bacteria themselves, human behavior, the environment, or a combination of all three could be the root cause.

Is this bacterial infection different?

The outbreak appears to be caused by group B meningococcal bacteria, according to preliminary analysis. However, this is not a single entity – it encompasses over a hundred strains which all act differently in the human body.  Some are more harmful and more likely to cause meningitis and invasive diseases. In the laboratory, samples taken from patients are being analyzed. It appears to be a strain that has been around for five years so far. If the bacterial genetic code has mutated in a significant way, further investigation will reveal this. The behavior and growth of the bacteria in the laboratory will be examined by additional tests. However, there are additional factors that may facilitate the meningitis bacteria's entry into the body from the nose. This is well-known to be the case in the Meningitis Belt, which stretches from Senegal to Ethiopia across 26 countries in sub-Saharan Africa. Dust, high temperatures and low humidity throughout the dry season are thought to damage the back of the throat and give the bacteria a route into the body.  This triggers regular epidemics.

 Smoking has been shown to have a similar effect and there is speculation about vaping in this outbreak.  Meningitis could spread to a large number of people through saliva by sharing vapes with friends, which is more common than sharing a single cigarette. The act of vaping itself could irritate the airways and is known to cause inflammation, which some have argued could also make it easier for bacteria to get into the body.

 However, the fact that vaping is not a new practice or a Kent phenomenon does not, on its own, account for the unusual nature of this outbreak.

Super-spreading event

A nightclub in Canterbury is thought to be the centre of the Kent outbreak (Image: Getty Images)

The fact that so many people needed to be treated in the hospital at the same time suggests that they were also infected around the same time. With at least 11 cases linked to Club Chemistry, the head of the UK Health Security Agency, Susan Hopkins, said: "This looks like a super spreader event with ongoing spread within the halls of residence in the universities."

 When more people are infected than you would expect, these are events known as super-spreading. The meningitis bacteria are difficult to spread. They usually spread within households where people spend a lot of time in the same room. Other mixing pots include nightclubs and university residence halls, which are not unique to this outbreak but may provide the bacteria with an opportunity to spread. When it comes to other respiratory infections like the flu or COVID, people who don't usually show symptoms but have very high levels of the virus can unintentionally spread the infection to a lot of people. It is unknown whether something akin took place in Club Chemistry. The University of Sheffield's Prof. Andrew Lee suggests that people who have other infections that make them cough and sneeze a lot may have made it easier for the bacteria that cause meningitis to spread in the club. He stated, "There are some reported synergies between viral respiratory infections like the flu and meningococcal infections as the viral infections may potentiate the spread" in the scientific literature. There are also questions about whether some people are born more vulnerable and at greater risk of severe outcomes.  It's also possible that young people who were a part of the Covid lockdowns as teenagers did not have the usual immunity to protect them. Preston asserts, "But that would be across the UK – so it may be one of the factors, but it cannot be the sole explanation." We are still looking for answers to the many questions surrounding this outbreak. According to Hopkins, "I can't yet say where the initial infection came from, how it has gotten into this cohort, and why it has created such an explosive amount of infections."

Source: BBC