There were 1,614 new cases of whooping cough in October, according to the Health Protection Agency (HPA), taking the total to 7,728 this year.
Thirteen infants have died so far this year from the largest outbreak of whooping cough since the early 1990s.
Levels of infection are now 10 times higher than the same period in 2008, when there were 797 cases during the last significant peak.
Experts repeated their calls for pregnant women to get vaccinated to protect their unborn children but warned it was too soon for the national vaccination programme to have had an effect on the number of cases being seen.
Dr Gayatri Amirthalingam, consultant epidemiologist at the HPA, said: 'We strongly recommend all pregnant women take up the offer of vaccination. Parents should also ensure their children are vaccinated against whooping cough on time, even babies of women who’ve had the vaccine in pregnancy – this is to continue their baby’s protection through childhood.'
RCGP immunisation lead Dr George Kassianos said immunising pregnant women alone would not be enough to counter the outbreak. He repeated his previous calls for teenagers to be vaccinated to prevent the disease spreading, and encouraged GPs to work closely with midwives to boost uptake among pregnant women.
He added that the NHS should consider vaccinating fathers of newborns as well.
He said: 'Such measures can help towards ending the increase we currently see in pertussis infection in the UK.'