An Illinois resident was discovered to have been infected with the COVID-19 virus before the widespread pandemic was reported in the United States, a new study published by the Clinical Infectious Diseases journal said.

Nine participants were included in the study, five of which were from Illinois, while the other four were from Massachusetts, Mississippi, Pennsylvania, and Wisconsin. The researchers found out that the individuals were infected with the coronavirus before the first cases were reported in America.

There have been some very rare and irregular cases in the United States, but were not conclusive enough to have been noticed by experts, the Centers for Disease Control and Prevention's (CDC) Natalie Thornburg said.

Early Confirmed Cases

The study is not definitive and many remain doubtful of the possibility, but some officials are slowly accepting the idea that there have been some cases of the COVID-19 virus in the U.S. before the massive outbreak. Despite the skepticism surrounding the research, the study's results were consistent, Thornburg said.

Medical professionals worldwide were made aware of the existence of the COVID-19 virus in late 2019 when China reported cases of the infection in Wuhan. The first reported case in the United States was from a Washington state man who traveled home to the U.S. from Wuhan, China on January 15, 2020, Newsweek reported.

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The study also allowed health experts to discover the information regarding the first infections of COVID-19 across the United States. Josh Denny, M.D., M.S., Chief Executive Officer of the NIH's All of Us and an author of the study said the results of the research were crucial for informing public health strategies and preparedness.

Denny said false positives were a major challenge in studies such as this one, even more so when the infection was not very common. This was the situation scientists were faced with during the early stages of the coronavirus pandemic. CDC guidelines were followed for sequential testing on two separate platforms.

Limitations of the Study

However, researchers of the study said there were several limitations hampering the reliability of the analysis. First, there were too few samples collected from across many states in the United States. Second, experts were not sure of whether the infected participants contracted the virus during travel or from local communities, the NIH reported.

Two of the confirmed cases were found to be from a time before public health officials confirmed the COVID-19 had entered the United States. The discovery of the cases gives health experts more knowledge about the geography of the coronavirus pandemic's spread, Johns Hopkins Bloomberg School of Public Health in Baltimore Keri Althoff the lead author of the study said.

Althoff noted the results of the study showed health officials that testing should be done early as soon as possible when an outbreak is discovered. Only a few people with symptoms were tested and confirmed to be infected with the COVID-19 virus during the early days of the pandemic due to the limited number of tests and lab availability, the Wall Street Journal reported.

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