Coronavirus infections in working adults. Eight-year study with 229 E and OC 43.

Respiratory infections due to coronaviruses 229 E and OC 43 in insurance company employees occurred almost exclusively in the winter and spring. Four per cent of all colds and 8 per cent of winter and spring colds were serologically related to infection with one of the two viruses. Studies of a group of families of employees showed that the prevalence of antibodies to 229 E and OC 43 increased with age. The infection rate for both coronaviruses in employees observed for one year or longer was 14.5 infections per 100 persons per year, and approximately one·third were reinfections rather than primary infections. Reinfections were commonly associated with respira· tory symptoms. Colds associated with coronavirus 229 E were mild and nasal symptoms were pre· dominant. Infections due to OC 43 coronavirus were associated with cough and pharyngitis as well as coryzal symptoms.