CANTERBURY — A meningitis outbreak centered on a Canterbury nightclub has resulted in 20 confirmed cases and two deaths. All 20 patients required hospital treatment, with nine needing intensive care.

The first analysis of bacteria grown from an infected patient was published in a recent report. The report identified multiple mutations that may alter the bacterium's behaviour. The strain has been circulating in the UK for five years and had not caused an outbreak of this kind before.

Health Secretary Wes Streeting has asked the Joint Committee on Vaccination and Immunisation to review the decision not to vaccinate teenagers. There have been calls to consider a meningitis immunisation programme for university students due to their greater risk.

At the time of reporting, there were no newly confirmed cases for a week. The UK Health Security Agency has attempted to anticipate potential cases and outbreaks over the next six months. The probability of additional cases or clusters is estimated at 40-50%. The probability of widespread outbreaks is estimated at less than 5%.

Researchers are examining genetic changes in the meningococcal bacterium and possible decreased immunity in people. Researchers are investigating whether current teenagers have lower immunity to meningococcal bacteria. Studies on the blood of healthy 15 to 22-year-olds are planned to assess antibody levels to meningococcal bacteria.

University students are 11 times more likely to have meningitis than non-students. Teenagers and young adults have an increased risk of meningitis compared to other age groups. Socialising and moving around the country exposes individuals to different strains of meningococcal bacteria and increases their risk of meningitis.

A meningitis B vaccine was introduced in the UK in 2015 for babies and toddlers at high risk. The vaccine was previously considered too expensive for the number of lives saved for the NHS to fund it for teenagers. There is a second, smaller peak in risk of meningococcal disease in late teens and early adulthood.

Meningococcal bacteria are spread by close physical contact. Bacterial meningitis normally appears as random, isolated one-off cases. Meningococcal bacteria often harmlessly infect people but rarely invade the body to cause meningitis and sepsis.

The outbreak was described as unusual and unprecedented due to the number of cases confirmed in a short period. Meningitis can cause critical illness within hours. A whooping cough outbreak that started in 2011 led to a temporary vaccination programme for pregnant women that later became routine.