A new antibody testing study conducted by the National Institutes of Health’s (NIH) All of Us Research Program has just altered the timeline for SARS-CoV-2 growth in the United States, revealing the viral cause of COVID-19 may have been in-country nearly a month earlier than established.
Until now, the first detected case of COVID-19 in the United States was thought to have appeared near the end of January 2020.
The new NIH study, published in Clinical Infectious Diseases, expanded on findings from a Centers for Disease Control and Prevention (CDC) study from last year. This latest report found that SARS-CoV-2 infections had appeared in five states earlier than previously realized, following analysis of more than 24,000 stored blood samples. These samples were all donated from across the country between Jan. 2 and March 18, 2020.
“This study allows us to uncover more information about the beginning of the U.S. epidemic and highlights the real-world value of longitudinal research in understanding dynamics of emerging diseases like COVID-19,” said Dr. Josh Denny, CEO of All of Us and an author of the study. “Our participants come from diverse communities across the U.S. and give generously of themselves to drive a wide range of biomedical discoveries, which are vital for informing public health strategies and preparedness.”
Denny and his fellow researchers found antibodies to SARS-CoV-2 through the use of two different serology tests. To be registered as positive, the samples had to turn up positive results on both tests as a check for false positives. The newly discovered cases were in Illinois, Massachusetts, Mississippi, Pennsylvania, and Wisconsin, appearing as early as Jan. 7, 2020. Given that these samples were collected before the first reported cases within those states, the researchers have taken this as an emphasis point for the need to expand testing as quickly as possible.
“Antibody testing of blood samples helps us better understand the spread of SARS-CoV-2 in the U.S. in the early days of the U.S. epidemic when testing was restricted, and public health officials could not see that the virus had already spread outside of recognized initial points of entry,” said Dr. Keri Althoff, lead author and associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health in Baltimore. “This study also demonstrates the importance of using multiple serology platforms, as recommended by the CDC.”
While more data will be forthcoming, the study authors admitted to several limitations in the study. For example, its sample numbers by state varied and were in some cases low, nor did the author know whether participants with positive samples became infected during travel or while at home.