But the finding may send an important message to parents who (despite doctors' recommendations) are questioning the need to immunize their children against swine flu because they seemed to have already had the disease, said Susan Coffin, director of infection prevention and control at Children's Hospital.
"Maybe their child is still susceptible to H1N1 and should still get the vaccine," Coffin said.
For years, rhinoviruses have been the Rodney Dangerfields of microbes. Even major institutions have found plenty of reasons not to pay them much mind. They are exceedingly common, they cause mere colds, they come in hundreds of hard-to-identify strains that make testing a challenge, and there is no effective treatment anyway.
Neither the federal government nor the states track rhinoviruses in the way they do "surveillance" for influenza, based on samplings of doctor diagnoses, emergency-room visits, and lab reports. Children's Hospital of Philadelphia is one of the few institutions that routinely checks for them whenever it tests for influenza and other viruses.
Rhinovirus - named after the Greek word for nose - is known to circulate year-round, and typically to peak shortly before and after flu season. Children's recorded rising numbers in September, right on schedule. Then they kept rising.
"The rate of activity was unbelievably high," Richard L. Hodinka, director of the clinical virology laboratory, said yesterday. "What got my attention was not only the numbers we were seeing in the laboratory, but physicians saying there was severe disease."
'Looking back ...'