The Food and Drug Administration (FDA) approved the first blood test for seeing if patients were infected with COVID-19 in the past but have since recovered, a key component of many plans looking at restarting the U.S. economy amid the pandemic.
Dr. Stephen Hahn, commissioner of the administration, announced the approval during an interview with CBS News Radio on Thursday.
The serology test will allow laboratories “to determine exposure in the antibodies,” detecting which people have been exposed to the CCP (Chinese Communist Party) virus, commonly known as novel coronavirus, which causes the disease COVID-19.
“It has a really important role to play in the surveillance of the disease, particularly because this virus is different from others in that we suspect that there’s a large percentage of people who are asymptomatic but who have had it and gone over without even knowing they had it,” Hahn said.
“It’s going to help us determine what is what we call the attack rate of the virus, how many people it could attack and what was the spread like.”
The test is not a substitute for a diagnostic test, Hahn cautioned.
Most tests for the CCP virus are focused on looking for signs of the illness while antibody tests focus on the body’s response to the virus. Patients who had the virus and have since recovered can be detected through antibody tests, suggesting an immunity to the illness.
Cellex Inc., a North Carolina-based company, was informed on Wednesday of the emergency use authorization for its test, which detects immunoglobulin M and immunoglobulin G antibodies against the CCP virus.
Antibodies are generated as part of the immune system’s response to the virus and are “generally detectable in blood several days after initial infection,” Denise Hinton, the FDA’s chief scientist, wrote in a letter (pdf) to the company. But, she added, “levels over the course of infection are not well characterized.”
Positive results “could occur after infection and can be indicative of acute or recent infection,” she wrote.
The FDA approved the test based on scientific evidence it was presented.
“It is reasonable to believe that your product may be effective in diagnosing COVID-19, and that the known and potential benefits of your product when used for diagnosing COVID-19, outweigh the known and potential risks of your product,” Hinton wrote.
Emergency use authorization lets the FDA sidestep normal regulatory procedures to speed up approval of key items during the COVID-19 pandemic.
The authorization came after a different company, BodySphere, claimed its serology test received FDA approval. The administration denied the claim and the company later retracted its statement.
Reports based on a press release BodySphere were also deleted, including reports from Axios and Reuters.
Other companies are also developing serology tests, as is the Centers for Disease Control and Prevention. The federal agency said its test will “assist with efforts to determine how much of the U.S. population has been exposed to” the CCP virus.
“The serology test will look for the presence of antibodies, which are specific proteins made in response to infections. Antibodies can be found in the blood and in other tissues of those who are tested after infection. The antibodies detected by this test indicate that a person had an immune response to” the virus, “whether symptoms developed from infection, or the infection was asymptomatic. Antibody test results are important in detecting infections with few or no symptoms,” it stated.