Parents have been urged to remain vigilant after four children were rushed to hospital with suspected meningitis.
One was left fighting for her life.
Health bosses said none of the cases appeared to be linked and the children were making a good recovery.
Earlier this month a two-year-old contracted meningitis and two pensioners were diagnosed with the disease in December.
Experts said the latest cases were likely to have arisen as a result of children returning to school after the break.
Two of the victims, girls aged two and three, were from Hastings.
One was taken to the Royal Alexandra Children's Hospital in Brighton for treatment and the other to St Thomas's Hospital in London.
The others were a 13-year-old girl from Hove and a 15-year-old girl from Piddinghoe, near Newhaven.
East Sussex, Brighton and Hove Health Authority said there was no cause for alarm but urged parents to remain vigilant.
Dr Angela Iverson, consultant in communicable diseases, said: "The increase in cases is probably attributable to children returning to school after the break.
"The confirmed cases were not C-strain meningitis which has largely been eradicated after children were immunised last year.
"Current thinking is that it will be about five years before a vaccine against meningitis B is available."
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