Cases of whooping cough have more than doubled in the last year - although peaks of this kind are normal, according to the Health Protection Agency (HPA).
Figures for England and Wales show there were 421 cases in 2010, jumping to 1,040 in 2011.
Increases in whooping cough are usually seen every three to four years and the 2011 data appears to be in line with the last peak in 2008, when there were 902 cases, the HPA said.
A vaccination programme exists for young children but over the last few months, cases have increased among those aged 15 to 40.
While whopping cough can cause nasty symptoms in adults, it does not usually cause any long-lasting complications and can be treated with antibiotics.
However, adults are more infectious than younger people and tend to spread the illness more easily.
In the very young, whopping cough can be a serious illness and can lead to death in some cases.
Babies and children can often make a distressing "whoop" sound while gasping for air after a coughing fit.
Older children and adults tend to suffer a prolonged cough.
Latest UK figures show 94.8% of children had their first jab to protect against whooping cough by the time they were one-year-old.
By the age of five, 87.7% of children in the UK had had their first jab and boosters.
Children are offered whooping cough vaccine at two, three and four months of age as part of the combined jab which also protects against diphtheria, polio, Haemophilus influenzae type b - a cause of meningitis - and tetanus.
Dr Mary Ramsay, head of immunisation at the HPA, said: "We usually see a rise in cases of whooping cough every three to four years as the disease peaks in cycles, with 2008 being the last peak year.
"The uptake of the vaccine which protects against whooping cough is very good but it is a highly infectious disease so when there is a case it can spread quickly.
"Parents should ensure their children are up to date with their vaccinations so that they are protected at the earliest opportunity.
"The pre-school booster is also important, not only to boost protection in that child but also to help prevent them passing the infection on to vulnerable babies, as those under four months cannot be fully protected by the vaccine."
The HPA has now written to GPs to remind them of the signs and symptoms of whooping cough and to report cases quickly.