Evolution of the monthly SARS-CoV-2 real-time RT-PCR positivity ratio in a-/pre-symptomatic patients screened pre-hospitalization/pre-surgery by ten-year age group as a function of time (from 1 April 2020 to 31 March 2021).
The black solid line shows the age-weighted overall SARS-CoV-2 positivity ratio based on the age distribution in Belgium anno 2020. Error bars represent 95% exact Clopper-Pearson confidence limits for the age-specific positivity ratios.