Reuters Health

　　By Megan Rauscher

　　Thursday, October 6, 2005

　　NEW YORK (Reuters Health) - Otherwise healthy preschool-age children drive the spread of influenza in the community, a finding that could have major implications for immunization policy, investigators contend.

　　"What we found was quite striking," Dr. John S. Brownstein from Children's Hospital Boston noted in an interview with Reuters Health. In all six healthcare settings monitored —— including ambulatory care sites and emergency departments —— "3- and 4-year-olds were consistently the first age to get infected with influenza," he said.

　　This age group developed influenza-like illnesses as early as late September, while younger children showed up 1 or 2 weeks later, followed by older children in October and adults in November.

　　The findings, based on influenza surveillance data spanning four recent flu seasons for the greater Boston area, are reported in the American Journal of Epidemiology.

　　Current immunization policies recommend universal influenza vaccination for the elderly and for children 6 to 23 months of age. Influenza vaccination is currently advised for children 2 years of age or older only if they have high-risk medical conditions.

　　Brownstein said the current findings hint that a public health strategy that targets individuals at the front lines —— those who are becoming infected first and are spreading infection to other age groups —— might have significant benefits in curbing the spread of influenza within communities.

　　Dr. Kenneth D. Mandl, also from Children's Hospital Boston and co-author of the report, told Reuters Health that "on the one hand, it is not surprising that preschoolers are bringing home infections into the family. There is ample medical literature to show that young kids do spread influenza throughout households and vaccinating them will reduce household spread."

　　What's new about their study, he noted, "is that it shows that these kids seem to be having a very large impact on the community-wide spread of influenza starting right at the beginning of each year's influenza epidemic. What we didn't know before is that 3- to 4-year-olds really seem to spark the whole epidemic."