FREQUENCY AND NATURAL-HISTORY OF RHINOVIRUS INFECTIONS IN ADULTS DURING AUTUMN

Human rhinovirus (HRV) accounts for a significant portion of common-co ld illness, with the peak incidence being in the early fall, Three hun dred forty-six adults mho had self-diagnosed colds of 48 h or less wer e enrolled in a study during September and October 1994 to determine t he frequency and clinical course of HRV infections, Nasal wash specime ns for viral culture anal reverse transcription-PCR (RT-PCR) for HRV R NA and human coronavirus OC43 and 229E RNA detection were collected an enrollment, and participants recorded their symptoms twice daily for 14 days, Middle ear pressure (MEP) was measured with a digital tympano meter on days 1 and 7, Picornaviruses (224 HRV and 7 enterovirus isola tes) were detected by culture in 67% (231 of 346) of the subjects, Amo ng 114 samples negative by culture, HRV was detected by RT-PCR in 52 ( 46%) for an overall picornavirus infection rate of 82% (283 of 346 sub jects), among the remaining 62 negative samples, human coronavirus RNA was detected bg RT-PCR in 5 patients, so that 288 (83%) of patients h ad documented viral infection, The first symptom noticed most often wa s sore throat (40%) in HRV culture-or PCR-positive patients and stuffy nose in HRV-negative patients (27%), No differences in symptom scores over time or in the presence of individual symptoms were noted betwee n groups. The median duration of the cold episodes was 11 days in HRV culture-positive patients, 9.5 days in HRV RT-PCR-positive patients, a nd 11.5 days in HRV-negative patients, On enrollment, abnormal MEPs (l ess than or equal to -100 or greater than or equal to +100 mm of H2O) were found for 21% of HRV culture-positive patients, 14% of HRV RT-PCR -positive patients, and 10% of HRV-negative patients, No important dif ferences in the clinical course of HRV culture-positive, HRV culture-n egative and RT-PCR-positive, or HRV-negative colds were found, These r esults represent the highest frequency of virologically confirmed natu ral colds to date and document the importance of rhinoviruses as the c ause of colds during fall months.