The viruses associated most frequently with the "common cold" are rhinoviru
ses and coronaviruses, The first prospective cohort study to determine the
prevalence of rhinovirus and coronavirus infections in patients of all ages
hospitalized for acute respiratory illnesses is described. Hospital admiss
ions for acute respiratory illnesses were identified, and cell culture for
rhinovirus and serologic assays on paired sera for coronaviruses 229E and O
C43 were performed. A total of 61 infections with rhinoviruses and coronavi
ruses were identified from 1198 respiratory illnesses (5.1%); in addition,
9 additional infections associated with greater than or equal to1 other res
piratory viruses were identified. Of those infected with only rhinovirus or
coronavirus, underlying cardiopulmonary diseases were present in 35% of th
e patients aged <5 years, in 93% aged between 5 and 35 years, and in 73% ag
ed >35 years. The predominant clinical syndromes varied by age: pneumonia a
nd bronchiolitis in children aged <5 years; exacerbations of asthma in olde
r children and young adults; and pneumonia and exacerbations of chronic obs
tructive pulmonary disease and congestive heart failure in older adults. Th
erefore, rhinovirus and coronavirus infections in hospitalized patients wer
e associated with lower respiratory tract illnesses in all age groups.