People wait in long lines for their tests at a COVID-19 testing center within the Lincoln Park Recreation Center, Los Angeles, California, the United States, Jan. 6, 2021. One in five people in Los Angeles County who are tested are carrying the COVID-19 virus, public health authorities of the most populous U.S. county said on Wednesday. According to the county's Department of Public Health, the test positivity rate increased to 21.8 percent on Wednesday amid the steepest rise in COVID-19 cases. On Nov. 1, the test positivity rate was 3.8 percent. (Photos: Xinhua)

People wait in long lines for their tests at a COVID-19 testing center within the Lincoln Park Recreation Center, Los Angeles, California, the United States, Jan. 6, 2021. One in five people in Los Angeles County who are tested are carrying the COVID-19 virus, public health authorities of the most populous U.S. county said on Wednesday. According to the county's Department of Public Health, the test positivity rate increased to 21.8 percent on Wednesday amid the steepest rise in COVID-19 cases. On Nov. 1, the test positivity rate was 3.8 percent.

People wait in long lines for their tests at a COVID-19 testing center within the Lincoln Park Recreation Center, Los Angeles, California, the United States, Jan. 6, 2021. One in five people in Los Angeles County who are tested are carrying the COVID-19 virus, public health authorities of the most populous U.S. county said on Wednesday. According to the county's Department of Public Health, the test positivity rate increased to 21.8 percent on Wednesday amid the steepest rise in COVID-19 cases. On Nov. 1, the test positivity rate was 3.8 percent.

People wait in long lines for their tests at a COVID-19 testing center within the Lincoln Park Recreation Center, Los Angeles, California, the United States, Jan. 6, 2021. One in five people in Los Angeles County who are tested are carrying the COVID-19 virus, public health authorities of the most populous U.S. county said on Wednesday. According to the county's Department of Public Health, the test positivity rate increased to 21.8 percent on Wednesday amid the steepest rise in COVID-19 cases. On Nov. 1, the test positivity rate was 3.8 percent.

People wait in long lines for their tests at a COVID-19 testing center within the Lincoln Park Recreation Center, Los Angeles, California, the United States, Jan. 6, 2021. One in five people in Los Angeles County who are tested are carrying the COVID-19 virus, public health authorities of the most populous U.S. county said on Wednesday. According to the county's Department of Public Health, the test positivity rate increased to 21.8 percent on Wednesday amid the steepest rise in COVID-19 cases. On Nov. 1, the test positivity rate was 3.8 percent.

People wait in long lines for their tests at a COVID-19 testing center within the Lincoln Park Recreation Center, Los Angeles, California, the United States, Jan. 6, 2021. One in five people in Los Angeles County who are tested are carrying the COVID-19 virus, public health authorities of the most populous U.S. county said on Wednesday. According to the county's Department of Public Health, the test positivity rate increased to 21.8 percent on Wednesday amid the steepest rise in COVID-19 cases. On Nov. 1, the test positivity rate was 3.8 percent.