A medical worker at a COVID-19 drive-thru testing site uses a swab to take a sample at the George Washington University Hospital in Washington D.C., the United States, on April 9, 2020. (Photo by Ting Shen/Xinhua)

A medical worker at a COVID-19 drive-thru testing site uses a swab to take a sample at the George Washington University Hospital in Washington D.C., the United States, on April 9, 2020. (Photo by Ting Shen/Xinhua)

Photo taken on April 9, 2020 shows a COVID-19 drive-thru testing site at the George Washington University Hospital in Washington D.C., the United States. (Photo by Ting Shen/Xinhua)

A medical worker at a COVID-19 drive-thru testing site uses a swab to take a sample at the George Washington University Hospital in Washington D.C., the United States, on April 9, 2020. (Photo by Ting Shen/Xinhua)

Medical workers at a drive-thru testing site prepare for the COVID-19 test at the George Washington University Hospital in Washington D.C., the United States, on April 9, 2020. (Photo by Ting Shen/Xinhua)

A staff member directs cars to a COVID-19 drive-thru testing site at the George Washington University Hospital in Washington D.C., the United States, on April 9, 2020. (Photo by Ting Shen/Xinhua)