The currency and completeness of specialized databases of COVID-19 publications

Several specialized collections of COVID-19 literature have been developed during the global health emergency. These include the WHO COVID-19 Global Literature Database, Cochrane COVID-19 Study Register, CAMARADES COVID-19 SOLES, Epistemonikos' COVID-19 L-OVE, and LitCovid. Our objective was to evaluate the completeness of these collections and to measure the time from when COVID-19 articles are posted to when they appear in the collections.

We tested each selected collection for the presence of 440 included studies from 25 COVID-19 systematic reviews. We sampled 112 journals and prospectively monitored their websites until a new COVID-19 article appeared. We then monitored for 2 weeks to see when the new articles appeared in each collection. PubMed served as a comparator.

Every collection provided at least one record not found in PubMed. Four records (1%) were not in any of the sources studied. Collections contained between 83% and 93% of the primary studies with the WHO database being the most complete. By 2 weeks, between 60% and 78% of tracked articles had appeared.

Our findings support the use of the best performing COVID-19 collections by systematic reviews to replace paywalled databases.