A draft government report has projected that COVID-19 cases will reach 200,000 per day by June 1, an increase that would be accompanied by more than 3,000 deaths per day. Patients who have been infected with COVID-19 and who have recovered could be key to fighting this virus. One potential treatment uses the antibodies built up in the blood of COVID-19 survivors.

Early studies suggest the production of Immunoglobulin M(IgM) and Immunoglobulin G(IgG) in COVID-19 patients typically occurs between seven and 11 days after exposure, with IgM antibodies appearing first, followed by IgG antibodies.

The presence of these antibodies, which respond to specific antigens on the surface of the COVID-19, indicate that individuals have been exposed and their immune systems have reacted. However, even if the antibodies remain in the body, immunity remains unclear.

One looming question is how many people in different communities have been infected without knowing it because they had very mild, undocumented illnesses or did not access testing while they were sick?

A new study at the National Institutes of Health (NIH) in Bethesda, Maryland, has been initiatedto determine how many adults in the U.S. without a confirmed history of infection with COVID-19 have antibodies to the virus. This is a serosurvey, and researchers will collect and analyze blood samples from an estimated 15,000 participants (18 years of age and older) who have not had a confirmed history of COVID-19 or current symptoms in an endeavor to provide critical data for epidemiological models.

The study is conducted by researchers at the National Institute of Allergy and Infectious Diseases (NIAID) and the National Institute of Biomedical Imaging and Bioengineering (NIBIB) and supported by the National Center for Advancing Translational Sciences (NCATS) and the National Cancer Institute (NCI).

Study participants are required to attend a virtual clinic visit, complete a health assessment questionnaire, and provide demographic information before submitting samples in one of two ways: If participants work at the NIH Bethesda campus, blood will be drawn at the NIH Clinical Center. The remaining participants will use blood collection kits shipped to them from a medical device company in Torrance, California. After following the detailed instructions on collecting a microsample of blood, participants will mail the sample back for laboratory analysis.

The investigators will analyze blood samples for two types of antibodies, anti-SARS-CoV-2 S protein IgG and IgM, using an enzyme-linked immunosorbent assay (ELISA). If blood samples contain antibodies against COVID-19, researchers will perform additional tests to evaluate the participant’s immune response to the virus.

These data may provide clues as to why these cases were less severe than those that lead to hospitalization. The results will help reveal the extent to which COVID-19 has spread undetected in the U.S. The study start date is May 12, with an estimated completion date of March 31, 2022.