Children who are taken to the doctor with a bad cough that has lasted for more than two weeks are quite likely to have whooping cough - even if they were vaccinated as a baby, researchers claim today.
Doctors from Oxford say they found that nearly 40% of such children had the infection, and they are asking GPs to think again when faced with diagnosing children with persistent coughs. Some children are being prescribed asthma drugs which they do not need. While vaccinated children are likely to get a milder form of the disease, they are at risk of passing it to young babies in the family who have not been immunised.
Whooping cough - also known as pertussis - is a bacterial infection that was once a serious killer. Before the introduction of the vaccine in the 1950s, there were 100,000 cases a year. A scare over safety in the 1970s led to a drop in vaccination to only 30% and there were epidemics in the late 70s and early 80s and 100 deaths.
The first symptoms of whooping cough are similar to those of a cold - runny nose, sneezing and a bit of a temperature. The cough is mild to begin with, and dry. But after a couple of weeks, the irritating cough turns into serious spasms which can last for more than a minute. The child may turn red or purple in the face.
The "whoop", from which pertussis gained its common name, is the sound the child tends to make at the end of the spasm, when he, or she, breathes in. Vomiting is also common. Small babies and infants may not whoop or vomit but may gasp for air and even temporarily stop breathing. Between these coughing spells, however, the child usually feels well.
Pertussis is highly contagious during the first couple of weeks before the characteristic cough begins - and therefore before anybody realises that the child has the disease. Children are vaccinated at two, three and four months old, and a preschool booster is given between the age of three and five. However, it is known that vaccine immunity wears off.
In the British Medical Journal, Anthony Harnden, from the department of primary care at Oxford University, and colleagues say studies in the US have shown that 20% of adults with a persistent cough are infected with pertussis.
Dr Harnden's team says it is hard for GPs who are faced with a child who has been coughing for weeks and anxious parents, to know what to diagnose and prescribe. They are also not expecting to be confronted with whooping cough.
If the child has the disease in a milder form they may not have the "whoop", although they are likely to suffer coughing spasms followed by vomiting. To establish how many children with persistent coughs have pertussis, researchers ran tests on 172 five and 16-year-olds who had been coughing for at least 14 days and had been brought to a GP in Oxfordshire. They found that 64 (37.2%) had been recently infected with whooping cough.
Children with pertussis were more likely to have whooping and vomiting than the other children with coughs, and two months after the start of their illness, 85% were still coughing. Infected children coughed for an average 16 weeks. "GPs should be alert to a potential diagnosis of whooping cough in any child who presents with a persistent cough," say the authors. "If whooping cough is diagnosed, parents can be told how long to expect the coughing to last, and children will not be prescribed unnecessary asthma drugs."
