Virginia's New Covid tracking app, COVIDWISE
vdh.virginia.gov
vdh.virginia.gov
With Canadian https://www.ctvnews.ca/health/coronavirus/covid-19-exposure-... and Irish apps already available, it seems like states should be able to copy from one of them.
https://www.telecompaper.com/news/most-irish-have-downloaded... says that 60% of Irish cellphone owners have downloaded it. Some people won't ever download it because of privacy paranoia but it'd be nice to get people who will a chance to do so.