US had Nearly 5 Times More COVID-19 Cases Than Reported In First Half of 2020 – Study Finds
An estimated 20 million Americans were infected with COVID-19 in mid-July 2020 – 17 million more than the three milion officially recorded, a new study has found.

The United States may have experienced nearly 17 million additional COVID-19 cases in the first six months of the COVID-19 pandemic, according to a new study by the National Institutes of Health (NIH).

The NIH study,  published this week in Science Translational Medicine, suggests that for every coronavirus infection recorded until mid-2020, nearly 4.8 more asymptomatic cases went undetected.  In the United States alone, a total of 16.8 million infections with SARS-CoV2 were undected, as of mid-July 2020 – meaning that as many as 20 million Americans were infected with COVID-19 by mid-July 2020 – in comparison to the the three million cases officially recorded in that period.

“This study helps account for how quickly the virus spread to all corners of the country and the globe,” said Bruce Tromberg,  director of the National Institute of Biomedical Imaging and Bioengineering (NIBIB), one of the NIH institutes that runs the NIH SARS-CoV-2 Seroprevalence Project, in a statement on Tuesday.

Blood samples were collected from 8,058 volunteer participants between 10 May and  31 July 2020, among people who were not previously diagnosed with COVID-19. Of the sampled blood, approximate 304 contained antibodies against COVID-19.

Based on the analysis of the data , NIH researchers estimated that for every diagnosed COVID-19 case during the spring and summer of 2020, there were 4.8 undiagnosed cases – representing an additional 16.8 million cases.

The research team observed that Black participants had the highest estimated rate of positive COVID-19 antibody tests (14.2%), followed by Native American/Alaska Native (6.8%), Hispanic (6.1%), white (2.5%) and Asian (2%) respondents. When comparing age groups, the youngest participants – those between the ages of 18 and 44 –  had the highest estimated rate, at 5.9%, the study found.  Women (5.5%) had a higher positivity rate than men (3.5%); and numbers for those living in urban areas (5.3%) were higher compared with rural participants (1.1%).

Pandemic Hallmark – Many People Infected with Few or No Symptoms

“A hallmark of the coronavirus pandemic is that there are people infected with the virus that causes COVID-19 who have few or no symptoms,” Dr Matthew Memoli, director of the Laboratory of Infectious Diseases Clinical Studies Unit at the National Institute of Allergy and Infectious Diseases, which participated in the research team, said in a statement. 

“While counting the numbers of symptomatic people in the United States is essential to contend with the impact of the pandemic and public health response, gaining a full appreciation of the COVID-19 prevalence requires counting the people who are undiagnosed.”

The research team also included scientists from the National Institute of Allergy and Infectious Diseases (NIAID), the National Center for Advancing Translational Sciences (NCATS); and the Frederick National Laboratory for Cancer Research, sponsored by the National Cancer Institute (NCI). 

The team argues that the USA’s official COVID-19 numbers should be revised upwards from the three million cases reported in mid-July 2020 to almost 20 million, once the proportion of asymptomatic positive results are included.

Said senior co-author Kaitlyn Sadtler, chief of the NIBIB Section on Immunoengineering: “This wide gap between the known cases at the time and these asymptomatic infections has implications not only for retrospectively understanding this pandemic, but future pandemic preparedness.”

The research team said they are currently following up with the study participants to evaluate the presence of antibodies after six and 12 months, as well as antibody reactivity to variants of concern, the medical research agency said

“The information will be invaluable as we assess the best public health measures needed to keep people safe, as new – and even more transmissible – variants emerge and vaccine antibody response changes over time,”  said Tromberg.

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