The Johns Hopkins Coronavirus Resource Center began providing COVID-19 testing data for the United States from publicly reported sources since March 7, 2021 when The Atlantic’s COVID Tracking Project end its year-long collection effort.
The Coronavirus Resource Center's files include Covid Tracking Project data up to March 3, 2021 and JHU-collected data from that date forward. The data dictionary details all the variables' name equivalences to match CTP to JHU names.
Changes in how Johns Hopkins calculates test positivity for several states compared to CTP resulted in spikes visible on March 3.
The CRC explains its positivity calculation methodology here. Since beginning to collect testing data directly from state and county government sources the CRC has routinely reviewed positivity calculations and recently identified and ranked the five prevailing approaches used across the United States.
The CRC is providing an up-to-date, read only version of testing data in JSON format at this location: https://jhucoronavirus.azureedge.net/api/v1/testing/daily.json. This API contains only testing data at this time.
The CRC has provided a continuously updated source of COVID-19 data and expert guidance since the pandemic began in January 2020. Experts aggregate and analyze the best data available on COVID-19 — including cases, deaths, tests, contact tracing, and vaccinations — to help the public, policymakers and healthcare professionals worldwide respond to the pandemic.