The isolated effect of age on the risk of COVID-19 severe outcomes: a systematic review with meta-analysis.

Our results show a best-possible quantification of the increase in COVID-19 disease severity due to age. Rather than implementing age thresholds, prevention programmes should consider the continuous increase in risk. There is a need for continuous, high-quality research and 'living' reviews to evaluate the evidence throughout the pandemic, as results may change due to varying circumstances.