Clinical Impact of Human Coronaviruses 229E and OC43 Infection in Diverse Adult Populations

Background. The incidence and clinical impact of coronavirus (CoV) infection in elderly persons and those with underlying cardiopulmonary disease over a long duration is not well described. We determined the incidence and clinical impact of 229E and OC43 CoV in this population during 4 consecutive winters, and compared illnesses to influenza A, respiratory syncytial virus, and human metapneumovirus. Methods. CoV 229E and OC43 were detected by reverse transcription polymerase chain reaction and serology in 4 adult populations under surveillance for acute respiratory illness during the winters of 1999-2003. Cohorts included healthy young adults, healthy elderly adults, high-risk adults with underlying cardiopulmonary disease, and a hospitalized group. Results. Three hundred ninety-eight CoV infections were identified, with annual infection rates ranging from 2.8% to 26% in prospective cohorts, and prevalence ranging from 3.3% to 11.1% in the hospitalized cohort. The incidence of infections with each strain was similar, although asymptomatic infection and viral coinfection was significantly more common with 229E than OC43 infection. Although the incidence and clinical manifestations were similar for each strain, OC43-infected subjects tended to seek more medical care, as OC43 was twice as common as 229E among the hospitalized cohort. Conclusions. CoV infections in the elderly are frequent, likely causing substantial medical disease burden.