This is much harder than it sounds. Facebook could help here: they could become the world's most important platform for clinical trial recruitment.
Facebook has 2.5B people and could automate all of this with a first party app.
More detail:
1) en.wikipedia.org/wiki/Patient_r…
2) zak-services.com/7-reasons-clin…
1) Digital diagnosis. Social network signals predict likelihood of contracting virus. People could opt-in to know this & in return share their data.
2) Community tools. People stuck at home need to re-establish local communities for childcare, etc.