  The scientific papers dealing with the novel betacoronavirus SARS-CoV-2 and
the coronavirus disease 2019 (COVID-19) caused by this virus, published in 2020
and recorded in the database PUBMED, were retrieved on April 27, 2020. About
20\% of the records contain Medical Subject Headings (MeSH), keywords assigned
to records in the course of the indexing process in order to summarise the
articles' contents. The temporal sequence of the first occurrences of the
keywords was determined, thus giving insight into the growth of the knowledge
base of the pandemic.
