Incidence of Medically Attended Respiratory Syncytial Virus and Influenza Illnesses in Children 6–59 Months Old During Four Seasons

Simpson, Melissa D.; Kieke, Burney A.; Sundaram, Maria E.; McClure, David L.; Meece, Jennifer K.; Sifakis, Frangiscos; Gasser, Robert A.; Belongia, Edward A.

During 4 influenza seasons (2006-2007 through 2009-2010) , MESA residents were screened and recruited by research staff during or after an outpatient, inpatient, or emergency department encounter for ARI. Research coordinators used an electronic appointment system to identify potential participants in primary care departments at the Marshfield Clinic main campus and a satellite clinic. Patients who were not approached during the clinical encounter were invited to participate by phone on the following day if they received an International Classification of Diseases, Version 9, Clinical Modification (ICD-9) diagnosis code indicating ARI. Potential participants with illness duration >7 days (or >10 days in [2006] [2007] were excluded to minimize false-negative test results. Children could be enrolled more than once per season for distinct illness episodes; an exclusion window of 21-28 days (depending on enrollment season) was applied to ensure that re-enrollment did not occur for the same illness episode.