A SUSTAINED whooping cough epidemic in Victoria has led to a spike in the number of infected babies being admitted to hospital with life-threatening cases of the disease.

Department of Health figures show 2625 whooping cough cases to date this year, compared with 1992 for the same period last year and 730 in 2008.

A department spokesman said it was unclear what had caused the outbreak, but people should be vaccinated against the disease.

Whooping cough vaccines are given to babies at two, four and six months, in addition to booster shots at four and 15 years. But protection against the disease is not lifelong, lasting just six to 10 years after the vaccine is given.

Royal Children's Hospital paediatrician Jenny Royle said the increasing number of whooping cough cases in the community was reflected in the hospital's admissions. She said there was a large number of cases last year, when 27 babies presented to the hospital in serious condition.