PubMed
PubMed's Clinical Queries search for the most current filters covers General, Transmission, Mechanism, Diagnosis, Treatment, Prevention, Case Report, Forecasting and Long COVID.
Add NOT preprint[pt] to exclude preprints.
CDC
CDC Library's COVID-19 (2019 Novel Coronavirus) search.
NICE MEDLINE and Embase (Ovid) search filters for treating and managing COVID-19