[Seasonal patterns of coronavirus infections in Hamburg].

During a serological surveillance programme between October 1974 and September 1975 in Hamburg, 1624 sera from all age groups of the population were examined for the presence of coronavirus antibodies (OC 43 agent). 61,51% of the sera showed HI-titres between 1:8 and 1:128. The geometric mean antiboty titre (GMT) for the whole group was 1:12,2. The serological seasonal pattern suggests that coronaviruses are circulating the whole year in the urban population with a prevalence in the cold and a decrease in the warm season (June). The highest incidence of seropositive reactions (82,9%) was found in the 15-24 years old individuals (GMT 1:13,8). These data indicate an increased spread of coronaviruses in this segment of the population and a marked susceptibility of the group.