Whooping cough still infecting millions of vaccinated children

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Whooping cough still infecting millions of vaccinated children

By Nigel Hawkes, Health Editor

MILLIONS of British children have probably been infected with

whooping cough even though they have been immunised against it.

A study has found that nearly two in five children who went to their

GP with a persistent cough had suffered from whooping cough, though

very few doctors diagnose it. The results suggest that the whooping

cough vaccine is ineffective at preventing infection, but makes

symptoms less severe — thereby concealing just how common it remains.

In BMJ online, a team from the University of Oxford, the University

of Auckland in New Zealand and the Health Protection Agency report

that in 85.9per cent of the cases they saw, the children had been

vaccinated. But blood samples tested positive for antibodies to

Bordetella pertussis, the cause of whooping cough, indicating recent

infection.

The team studied 172 children aged 5-16 who visited their family

doctor with a cough lasting 14 days or more. Immunisation records

were checked, notes made on the symptoms and duration of cough, and

blood samples taken for testing. They found that 37.2 per cent of the

children had evidence of a recent pertussis infection. The results

suggest that the condition is " endemic among younger school-age

children " , they say, and that doctors should consider a diagnosis of

whooping cough even if the child has been immunised.

They also found that children with whooping cough were more likely to

have symptoms of vomiting and were more likely still to be coughing

two months after the start of their illness. They were also more

likely to cough more, and to disrupt their parents' sleep.

The danger is that cases will go undiagnosed, which could pose a risk

to younger siblings who have not yet been immunised. A correct

diagnosis also saves time and money on treatment and further tests

for conditions such as asthma.

" Younger children are more likely than adolescents to have a newborn

sibling to whom they could transmit the infection, with potentially

devastating consequences, " they say.

" For school-age children presenting to primary care with a cough

lasting two weeks or more, a diagnosis of whooping cough should be

considered even if the child has been immunised. " Whooping cough was

once one of the diseases that almost all children suffered, with

about 150,000 cases a year in Britain. But the introduction of the

pertussis vaccine in the late 1950s changed that. The number of cases

fell almost to zero by 1973.

Uptake was reduced after claims that the vaccine caused brain damage,

and cases increased between 1980 and 1985. By the time that the scare

had been dismissed as unfounded, there had been as many as 100

needless deaths.

Last year there were only 185 cases in babies under 12 months old,

104 cases in the 1-5 age group, and 83 in those aged 5-9. But this

study suggests that millions of cases are being missed. Doctors

usually diagnose the disease only in babies too young to have been

vaccinated, or in those with the characteristic whoop.

Harnden, a lecturer at Oxford and a GP, was the lead author

on the paper. He said the problem was that the vaccine did not last

very long, not that the immunisation policy was not working.

Children are immunised at the age of 2, 3 and 4 months, and are also

given a pre-school booster. The condition is not usually serious in

older children but can kill babies in their first year.

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