No new cases of meningitis linked to the outbreak in Kent have been detected, raising hopes that it has been well contained and has not led to people elsewhere catching the disease.

The number of people affected remains at 29, of which 20 are are confirmed and nine probable cases in what health officials say is an “explosive” outbreak – the biggest to occur in the UK in a generation.

Two of the 20 people confirmed with the disease have died: Juliette Kenny, 18, a secondary school student, and an unnamed University of Kent student. The other 18 are thought still to be in hospital.

Nineteen of the 20 confirmed cases were of meningitis B. The outbreak involves people who attended the Chemistry nightclub in Canterbury on 5, 6 and 7 March, including students from the city’s two universities.

The total number of cases has fallen from 34 on Friday to the 29 the UK Health Security Agency (UKHSA) reported on Sunday and Monday. Five cases were reclassified as a result of laboratory testing.

That number may fall further because more cases included in the 29 also look likely to be ”downgraded” and removed from the headline total.

“Whilst we expect some further probable cases to be downgraded in the coming days, this outbreak is not yet over,” a UKHSA spokesperson said.

The fact that the number of cases has not continued to rise since the outbreak first came to the UKHSA’s attention over the weekend of 13/14/15 March is grounds for optimism, health officials and experts believe.

Staff from Kent county council, NHS England and the UKHSA quickly began providing antibiotics and vaccines and tracing contacts of those known to have been infected.

“The lack of new cases is a good sign and may signal that the Kent outbreak has been contained,” said Simon Williams, a public health expert at Swansea University.

“However, we can’t rule out [that] there are no further cases linked to this outbreak because the latency period, the time between exposure and symptom or disease alert, for MenB can sometimes be longer than a few days.”

The lack of new cases was largely the result of prompt antibiotics and vaccine provision and contact tracing, he said.

But “this is also partly due to the nature of MenB, because it is not as contagious and easily spread as, say, flu or Covid. It does not infect as many people as this and so the precautions taken in Kent, including voluntary reduction of socialising, will also have played a part.”

As of lunchtime on Monday, 13,088 doses of antibiotics had been given out and 10,081 people had been vaccinated against meningitis B.

One health official said: “It looks promising and reassuring that cases have not increased. that suggests that there’s not a secondary chain of transmission beyond the already-known chain of transmission in Canterbury.”