A two year serological surveillance of coronavirus infections in Hamburg.

The occurrence of OC-43 coronarvirus-like infections in the population of Hamburg was determined by a monthly serological survey (hemagglutintion inhibition test [HI]) undertaken between October 1974 and October 1976. Studies of 3,016 sera revealed a high incidence of HI antibodies (58,2%). The frequency of seropositive reactions (= 1:8) and the geometric mean titer were higher in individuals 15 to 24 years old. Treatment of 50 postive sera (titer 1:16 -1:64) with receptor destroying enzyme, kaolin and ethacridin for elimination of nonspecific inhbitiros did not modify the HI-titer of the investigated sera. The serological seasonal pattern suggests that coronaviruses are circulating the whole year in the urban population with a prevlence in the fall-winter period. Of the 331 paired sera examined, 6.6% presented a four- to eightfold rise intiter within eight weeks.