BEIJING/WASHINGTON -- A newly released study by the US Centers for Disease Control and Prevention (CDC) found that COVID-19 was likely in the United States as early as mid-December 2019, weeks before the virus was first identified in China, boosting evidence suggesting that the coronavirus was spreading around the world earlier than previously known.

COVID-19 infections "may have been present in the US in December 2019," about a month earlier than the first case was officially confirmed in the United States, the CDC scientists wrote after finding evidence of infection in 106 of 7,389 blood donations from residents in nine states across the country, according to a study published Monday online in the journal Clinical Infectious Diseases.

EARLIER IN US

In the study, the CDC researchers found antibodies specific to the novel coronavirus in 39 samples from California, Oregon and Washington state collected between Dec 13 and Dec 16, and in 67 samples in Massachusetts, Michigan, Wisconsin or Iowa, and Connecticut or Rhode Island collected between Dec 30 and Jan 17.

The study also highlighted the value of screening routinely collected blood samples for evidence of viruses spreading in a population, said the researchers, adding the CDC is continuing to conduct ongoing surveillance using blood donations and clinical laboratory samples for COVID-19 infection in multiple sites across the country.

Before this latest report, the earliest case of the novel coronavirus in the United States was reported on Jan 19 this year, two days after domestic testing was initiated, according to the CDC.

Yet, some reports have suggested the entry of the virus into the United States may have occurred earlier than initially recognized, though widespread community transmission was not likely until late February, the study authors said.

Also, Michael Melham, mayor of Belleville in the US state of New Jersey, said in late April that he had tested positive for COVID-19 antibodies and believed he had contracted the virus in November last year, despite a doctor's reported assumption that what Melham went through was just flu.

"My fear is that there are many who dismissed a potentially positive coronavirus diagnosis as a bad flu," the mayor said in his statement.