NEW YORK - Doctors fail to diagnose the flu in the vast majority of young children, depriving them of medicines that could shorten their illness and keep them from spreading it to others, a study suggests.
Flu infections were missed in four out of five preschoolers who were treated for flu symptoms at a doctor's office or emergency room and in about three-quarters of those who were hospitalized, researchers report.
"Many of the children did not have a test performed and few of the children were sent home with a specific diagnosis of influenza," said Dr. Katherine A. Poehling, of Vanderbilt University Medical Center in Nashville, Tenn., who led the government-funded study.
If more doctors used a rapid flu test, more cases of flu could be detected and steps taken to prevent its spread, the researchers suggested. About a third of the children would have been candidates for medicines like Tamiflu, which work better to ease symptoms when given early, they said.
Their study is published in Thursday's New England Journal of Medicine. Two of the researchers report receiving grant support and consulting fees from spray flu vaccine maker MedImmune Inc.
Poehling and her research colleagues in Nashville, Rochester, N.Y., and Cincinnati, are part of a surveillance network sponsored by the Centers for Disease Control and Prevention.
Doctors aren't required to report cases of the flu, so the researchers set out to determine how many children under 5 actually get the flu. They will eventually use their findings to see how well flu shots work.
Over four years, the researchers did their own lab tests on young children who went to the doctor or were hospitalized with flu-like symptoms such as cough, runny nose and fever. Doctors didn't have the results but could have done their own test. A rapid test takes less than 30 minutes.
The study found that most of the children who had the flu weren't diagnosed with it by their doctors. Only 28 percent of the hospitalized flu cases and 17 percent of those who went to the doctor or emergency room were diagnosed with the flu. The rest of the preschoolers got diagnoses varying from asthma to pneumonia to a general viral illness.
The researchers determined that the annual hospitalization rate for young children with the flu was about 1 per 1,000, with most of them under 2 years. But many more children with the flu end up in doctor's offices and ERs. They calculated there were 56 visits per 1,000 children in a mild flu season and 122 visits in a moderate season.
"The burden is really large and we don't recognize how much there is," Poehling said.
The study's findings were presented earlier to a CDC panel which recommended flu shots be expanded this year to children ages 2 to 5 to reduce doctor and ER visits.
Flu shots were already recommended for those 6 months to 23 months.
Dr. W. Paul Glezen of Baylor College of Medicine in Houston said doctors need to get more accustomed to using antivirals such as Tamiflu in case there is a flu pandemic one day. He noted that few children in the study were treated because their flu infection wasn't detected.
"We better start using them now, then we'll be ready to use them effectively," if there's a pandemic, said Glezen, who wrote an editorial in the journal. He has received consulting fees from flu vaccine makers MedImmune, Chiron Corp. and GlaxoSmithKline PLC.