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Temporal rise in the proportion of younger adults and older adolescents among coronavirus disease (COVID-19) cases following the introduction of physical distancing measures, Germany, March to April 2020

Our take —

Adolescents and young adults, particularly those aged 20-24 years, represented an increasing share of reported COVID-19 cases in Germany during late March and early April, 2020. Although results are consistent with this age group exhibiting less adherence to social distancing measures than other age groups, there are other possible explanations for this result.

Study design


Study population and setting

Authors considered all reported COVID-19 cases among individuals aged 10-49 in Germany during two periods: March 2-15, 2020; and March 23-April 4, 2020. Cases were stratified into 5-year age groups, and relative risks were calculated for being a detected case in a given age group during the later period versus the earlier period.

Summary of Main Findings

There were changes in the age structure of cases between periods: cases were less likely in the later period to be at the youngest and oldest ends of the age spectrum. Cases were more likely to be in the 20-24 year age group in the later period relative to the earlier period (RR=1.40, 95% CI: 1.27,1.55). Cases were less likely to be in the 10-14 years(0.78 [0.64,0.95]), 40-44 years (0.90 [0.83,0.98]), and 45-49 years (0.83 [0.77,0.89]) groups.

Study Strengths

The methodology is easily replicable in other populations and time periods.


The age structure of reported case counts may not reflect the relative importance of those groups in driving transmission, let alone differential uptake of social distancing: possible confounding factors include the rollout of testing in different communities, changes in health-seeking behavior that vary by age, and spatial/geographical features of epidemic growth.

Value added

The study offers a simple but straightforward approach to examining temporal trends in the age structure of the COVID-19 epidemic.