NEW YORK (AP) — A brand new evaluation of blood samples from 24,000 Americans taken early final 12 months is the most recent and largest examine to counsel that the brand new coronavirus popped up in the U.S. in December 2019 — weeks earlier than instances had been first acknowledged by well being officers.

The evaluation is just not definitive, and a few specialists stay skeptical, however federal well being officers are more and more accepting a timeline in which small numbers of COVID-19 infections might have occurred in the U.S. earlier than the world ever grew to become conscious of a harmful new virus erupting in China.

“The studies are pretty consistent,” stated Natalie Thornburg of the Centers for Disease Control and Prevention.

“There was most likely very uncommon and sporadic instances right here sooner than we had been conscious of. But it was not widespread and did not develop into widespread till late February,” said Thornburg, principal investigator of the CDC’s respiratory virus immunology team.

Such results underscore the need for countries to work together and identify newly emerging viruses as quickly and collaboratively as possible, she added.

The pandemic coronavirus emerged in Wuhan, China in late 2019. Officially, the first U.S. infection to be identified was a traveler — a Washington state man who returned from Wuhan on Jan. 15 and sought help at a clinic on Jan. 19.

CDC officials initially said the spark that started the U.S. outbreak arrived during a three-week window from mid-January to early February. But research since then — including some done by the CDC — has suggested a small number of infections occurred earlier.

A CDC-led study published in December 2020 that analyzed 7,000 samples from American Red Cross blood donations suggested the virus infected some Americans as early as the middle of December 2019.

The latest study, published Tuesday online by the journal Clinical Infectious Diseases, is by a team including researchers at the National Institutes of Health. They analyzed blood samples from more than 24,000 people across the country, collected in the first three months of 2020 as part of a long-term study called “All Of Us” that seeks to track 1 million Americans over years to study health.

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Like the CDC study, these researchers looked for antibodies in the blood that are taken as evidence of coronavirus infection, and can be detected as early as two weeks after a person is first infected.

The researchers say seven study participants — three from Illinois, and one each from Massachusetts, Mississippi, Pennsylvania, and Wisconsin — were infected earlier than any COVID-19 case was originally reported in those states.

One of the Illinois cases was infected as early as Christmas Eve, said Keri Althoff, an associate professor at the Johns Hopkins Bloomberg School of Public Health and the study’s lead author.

It can be difficult to distinguish antibodies that neutralize SARS-CoV-2, the virus that causes COVID-19, from antibodies that fight other coronaviruses, including some that cause the common cold. Researchers in both the NIH and CDC studies used multiple types of tests to minimize false positive results, but some experts say it still is possible their 2019 positives were infections by other coronaviruses and not the pandemic strain.

“While it is entirely plausible that the virus was introduced into the United States much earlier than is usually appreciated, it does not mean that this is necessarily strong enough evidence to change how we’re thinking about this,” stated William Hanage, a Harvard University professional on illness dynamics.

The NIH researchers haven’t adopted up with examine members but to see if any had traveled out of the U.S. previous to their an infection. But they discovered it noteworthy that the seven didn’t dwell in or close to New York City or Seattle, the place the primary wave of U.S. instances had been concentrated.

“The query is how did, and the place did, the virus take seed,” Althoff stated. The new examine signifies “it probably seeded in multiple places in our country,” she added.


The Associated Press Health and Science Department receives assist from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely chargeable for all content material.

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