Temporal rise in the proportion of both younger adults and older adolescents among COVID-19 cases in Germany: evidence of lesser adherence to social distancing practices?

Edward Goldstein; Marc Lipsitch

We assess relative changes in the incidence of SARS-CoV-2 cases in different age groups in Germany using data on detected (reported) COVID-19 cases [7] . We note that for a given age group, the ratio between the number of detected COVID-19 cases and incident cases of SARS-CoV-2 infection (case-detection rate) in that age group may vary with time due to changes in healthcare-seeking behavior and other factors. To minimize the effect of relative changes, for the different age groups, in the case-detection rates with time, we restrict our analysis to individuals aged 10-49y only. We thus assume that for different age subgroups of that age group, the tendency to seek care or get tested does not change much over time relative to one another (e.g. there may be some increases with time in the likelihood of testing/seeking medical care for all individuals in the 10-49y age group, but not in specific age subgroups of that age group). We note that there is evidence that symptomatic older adults and younger children may be more likely to seek medical care/get tested compared to other age groups as the awareness about the epidemic increases with time, and those age groups are not included in this study.