The first analysis of bacteria grown from one infected patient was published this week.
It shows the strain has been circulating in the UK for five years and hasn’t caused this kind of outbreak before. The report also identified “multiple potentially significant” mutations that may alter the bacterium’s behaviour. Quite how important they are will require more work.
It is also unknown how widespread this particular variant is. Did it emerge in Kent and has since been wiped out by the mass use of antibiotics in response to the outbreak? Or will studies planned to assess the types of meningococcal bacteria people are harmlessly carrying reveal it is more widespread?
The other element is whether teenagers have built up less immunity to meningococcal bacteria during their lives.
This could be due to generational shifts in the nature of teenage life. These bacteria are spread by close physical contact. Could spending less time together in person, including Covid restrictions, and more time socialising through a screen lead to lower levels of immunity?
Studies on the blood of healthy 15 to 22-year-olds will assess antibody levels to see if current young adults have been left more vulnerable.
Any attempt to explain what happened in Kent is still mired in uncertainty. The best guesses of scientists chasing the answer is that it took a combination of the bacteria, immunity levels and the club setting to allow it to spread.
That makes predicting the future hard. The UK Health Security Agency has attempted to anticipate what could happen in the next six months, but has only “low confidence” in any of its forecasts.
It says more cases or clusters is a realistic possibility – meaning a 40-50% chance of it happening – but there is only a remote chance, less than 5%, of widespread outbreaks.
It’s also entirely plausible nothing like Kent will happen again.
It leaves a difficult challenge in deciding what should be done – particularly whether teenagers need extra protection by being offered a meningitis B vaccine.