Base Search Strategy
A good, fairly broad search for telemedicine/telehealth in general could look like the following in PubMed:
This produces a rather large number of results In PubMed. It also does not include variations such as "teledermatology" or "telegenetics". These variations could be added as needed.
Narrowing a Search
In order to narrow the search, you should add additional topic strings as needed. Examples of these strings include:
Another approach for narrowing the large telemedicine search can include including hedges from PubMed's Clinical Queries. These include
More details of what these filters actually add to your search strategy are available within Pubmed.
As a result, a final search for telemedicine and COVID-19 would look like
(Telemedicine[mesh] OR telemedicine[tiab] OR “virtual visit” OR "virtual appointment" OR "video visit" OR "online visit" OR "online appointment" OR “e-consult” OR “e-consultation” OR remote consultation[mesh] OR remote consult[tiab] OR remote consultation[tiab] OR teleconsultation[mesh] OR teleconsultation[tiab] OR teleconsult[tiab]) AND ("COVID-19"[tw] OR "COVID19"[tw] OR "novel coronavirus"[tw] OR "SARS-CoV-2"[tw] OR "2019-nCoV"[tw] OR "2019 coronavirus"[tw] OR "corona virus disease-19"[tw] OR "covid19"[tw])
As of March 22, 2020, this search produced only 5 results in PubMed. As of January 8, 2021, the search produced over 3000 results!