SANTIAGO (Reuters Health) - The flu vaccine may be helpful for healthy children as well as people older than 50, children with respiratory problems and people with weak immune systems, according to new findings presented here last week at the 3rd World Congress of Pediatric Infectious Diseases.

"Flu vaccination is the best strategy for preventing influenza infection. However, few data are available for healthy children, so we decided to measure the effectiveness of such immunization," Dr. Sussana Esposito of the University of Milan in Italy told Reuters Health.

Before last year's influenza season in Italy, Esposito and her colleagues administered a flu vaccine to 202 healthy children aged 6 months to 5 years. The doctors used an intramuscular vaccine called Inflexal V, made by Berna.

The vaccinated children showed a 31% reduction in respiratory illnesses in the following months compared with infants who did not receive the flu shot. In addition, they required fewer medical prescriptions during the influenza season and missed fewer days of school. The vaccination also led to a 56% decrease in lost days of work for mothers to care for the ill child.

These results support the recommendation that an annual influenza immunization not be restricted to children at risk, but should also be given to healthy infants because of its clinical and economic benefit, Esposito said in her presentation at the Congress.

In an interview with Reuters Health during the meeting, Esposito explained that there are two main limitations to implementing a new policy for flu immunization in healthy infants. One is the higher cost required for the vaccination of every child. The second concern is the intramuscular application of the vaccine.

"Many parents are not very comfortable with the idea of their kids receiving that kind of vaccine every year. But this concern will be easily overcome with the new flu vaccine spray that is expected to be available soon," Esposito said.

In a parallel presentation at the Congress, Dr. Terho Heikkinen of Turku University Hospital in Finland commented that children younger than one year are hospitalized for influenza-related illnesses at rates similar to those of high-risk adults. Recent studies also indicate that influenza is the leading cause of febrile convulsion in infants.

"All this evidence and the central role of children in the spread of influenza in the community are encouraging a more widespread vaccination of children against influenza," Heikkinen said.