The coronavirus pandemic may have started earlier than previously thought, according to scientists from the CDC.
A study from government scientists published November 30 appears to confirm what some health experts have suggested, patients infected with COVID-19 were in the US before the beginning of 2020.
“The findings of this report suggest that SARS-CoV-2 infections may have been present in the U.S. in December 2019, earlier than previously recognized. These findings also highlight the value of blood donations as a source for conducting SARS-CoV-2 surveillance studies,” the report states.
The first officially documented case of COVID-19 in the US was reported on January 19, a person who had returned to the US after traveling from China.
The World Health Organization was alerted to the novel coronavirus by officials in Wuhan, China on December 31, 2019. The CDC researchers say further reports have identified a patient in Wuhan with COVID-19 symptoms as early as December 1, 2019.
The study looked at more than 7,000 routine blood donation samples taken by the American Red Cross from people in nine states between December 13, 2019 and January 17, 2020.
They found COVID-19 antibodies in 106 samples, mostly from the states of California, Oregon and Washington, from blood collected between December 13-16, 2019. Other samples that indicated COVID-19 antibodies were from Connecticut, Iowa, Massachusetts, Michigan, Rhode Island, and Wisconsin taken in early January 2020.
“The presence of these serum antibodies indicate that isolated SARS-CoV-2 infections may have occurred in the western portion of the United States earlier than previously recognized or that a small portion of the population may have pre-existing antibodies that bind SARS-CoV-2,” the report states.
Scientists acknowledge that patients presenting with what is now known as COVID-19 symptoms before mid-January would likely not have had clinical samples taken or kept because of how new the virus was. Therefore, the CDC used the existing repository collected by the American Red Cross during their routine blood donation process.
“These specimens were previously archived for potential future studies to identify emerging transfusion-transmissible infections but were re-purposed for the present study,” researchers stated.
Researchers caution that these results are subject to limitations. Although they detected antibodies, that does not mean they are “true positive” COVID-19 tests. In order to get a true positive, a different test would need to be a run.