Search method
We searched the literature in Google Scholar and PubMed for articles
that were published from January 1 through May 5 2020. Searching was
concerned with asymptomatic coronavirus 2 (SARS-CoV-2) implications. We
used combinations of the search terms SARS-CoV-2, COVID-19, Corona
Virus, asymptomatic, presymptomatic, transmission, and implication.
“AND”, and “OR” Boolean operators were used to combine the search
terms especially in PubMed advanced searching. We included original
articles, brief reports, and correspondences and excluded reviews,
commentaries, opinions, and preprint manuscripts. We classified studies
as reporting epidemiology, geographic distribution, and timing of
asymptomatic implications of SARS-CoV-2.