COVID-19 Roundup: CDC Revises Quarantine Rule; Actual Cases 8 Times Higher; and Coronavirus in U.S. Traced to December 2019

CDC Revises COVID-19 Quarantine Guidance from 14 Days to 7-10 Days

The standard 14-day quarantine period for COVID-19 can be reduced to 10 days or seven, according to revised guidance from the U.S. Centers for Disease Control and Prevention (CDC), as the agency attempts to boost compliance with one of the most important actions that the public can take against spread of the coronavirus.

CDC previously recommended a 14-day quarantine period following potential exposure. CDC officials still support that longer period as the best option. However, the agency recognizes that the two-week quarantine rule is burdensome on many people — and more public participation can be gained with more flexible guidance.

Under the updated guidance, those without symptoms may end quarantine after seven days, followed by a negative test for the virus, or after 10 days without a negative test, agency officials said.

“We can safely reduce the length of quarantine, but accepting that there is a small residual risk that a person who is leaving quarantine early could transmit to someone else if they became infected,” said John Brooks, M.D., the CDC’s chief medical officer for COVID-19 response.

CDC officials also issued new testing guidance for travelers. Those planning a trip should get a coronavirus test one to three days in advance, and then be tested again three to five days after returning home. However, the CDC reiterated a pre-Thanksgiving recommendation against any travel this holiday season.

Total COVID-19 Cases in U.S. Could be 8 Times Greater Than Reported, Says CDC

The number of actual COVID-19 cases in the U.S. could be nearly eight times higher than the current number of infections being reported, says a new statistical model by scientists at U.S. the Centers for Disease Control and Prevention (CDC).

Between Feb. 27 and Sept. 30, there were 6.8 confirmed COVID-19 infections,. But when researchers adjusted for potential false-negative test results, incomplete reporting of cases and asymptomatic or mildly ill individuals who never got tested, they learned there actually may have been about 52.9 million infections.

The new model, published in the journal Clinical Infectious Diseases, indicates that nearly 53 million people in the U.S. had been infected with COVID-19 by the end of September. That number is about eight times higher than the 7.1 million confirmed cases that had been reported at that time.

What’s the reason for the major discrepancy? When researchers adjusted for potential false-negative test results, incomplete reporting of all cases and the number of asymptomatic or mildly ill persons who never got tested, they determined there may have actually been about 53 million coronavirus infections.

“From past experiences with influenza, another respiratory virus associated with a large proportion of mild illness and an overlapping clinical syndrome with COVID-19, laboratory-confirmed cases reported through surveillance systems underestimate total infections,” the study’s authors wrote.

Based on their findings, only 13 percent — or 1 in 8 cases — of total infections were identified and reported to the public through the end of September, researchers concluded.

“Improved estimates of SARS-CoV-2 infections, symptomatic illnesses, and hospitalizations over time, are critical to our understanding of the severity and burden of this new virus,” the researchers said.

COVID-19 Present in U.S. Weeks Earlier Than Previously Thought, New Study Says

The first confirmed COVID-19 case in the U.S. was diagnosed in a traveler returning from China on Jan. 19. But new research indicates that the coronavirus was in the U.S. weeks earlier than public health officials previously thought.

COVID-19 infections may have been present in the U.S. in December 2019, the new study’s authors said. Media reports in December first identified COVID-19, but only from it’s place of origin — Wuhan, China.

According to new findings published in the journal Clinical Infectious Diseases, the U.S. Centers for Disease Control and Prevention (CDC) analyzed blood donations collected by the American Red Cross from residents in nine U.S. states. They found coronavirus antibodies in 106 out of 7,389 blood donations. The CDC analyzed the blood collected between Dec. 13 and Jan. 17.

Researchers found COVID-19 antibodies in 39 samples, from California, Oregon, and Washington, as early as Dec. 13 to Dec. 16. Antibodies in a person’s blood are triggered as a defense mechanism after a person is exposed to a virus (in this case the coronavirus). They also detected antibodies in 67 samples from Connecticut, Iowa, Massachusetts, Michigan, Rhode Island, and Wisconsin in early January.

Despite the study’s findings, infectious disease experts say the coronavirus likely didn’t spread widely in U.S. communities until late February.