CDC suggests recovered COVID-19 patients have protection for 3 months

FILE -- A medical staff takes a sample for a voluntary coronavirus disease test (COVID-19) at the new corona test station at the 'Hochfelln' service station on the A8 motorway between Salzburg and Munich near Bergen, Germany, Thursday, July 30, 2020. German authorities worked through the night to clear a backlog of coronavirus tests from travelers after it emerged 900 people who were positive for COVID-19 had yet to be informed. (AP Photo/Matthias Schrader file)
FILE -- A medical staff takes a sample for a voluntary coronavirus disease test (COVID-19) at the new corona test station at the 'Hochfelln' service station on the A8 motorway between Salzburg and Munich near Bergen, Germany, Thursday, July 30, 2020. German authorities worked through the night to clear a backlog of coronavirus tests from travelers after it emerged 900 people who were positive for COVID-19 had yet to be informed. (AP Photo/Matthias Schrader file) (Copyright 2020 The Associated Press. All rights reserved.)

NBC – People who have recovered from COVID-19 can safely interact with others for three months, according to a recent update from the Centers for Disease Control and Prevention — suggesting that immunity to the virus may last at least that long.

The recent change is part of the agency's guidance on quarantining. It states that people should quarantine if they've been in close contact with someone who has COVID-19, "excluding people who have had COVID-19 within the past 3 months." People who have tested positive for the virus don't need to be tested again for up to three months, as long as they don't develop symptoms again.

Full coverage of the coronavirus outbreak

The CDC previously acknowledged that people who have recovered from COVID-19 can test positive for the virus for up to three months, though these positive results don’t mean that a person is still sick. Instead, the test may be picking up fragments of the virus’s genetic code. Dr. Brett Giroir, the undersecretary of health who leads coronavirus testing for the White House, has advised people against being tested again after they recover.

However, the update goes one step further, suggesting that people who have recovered are protected from getting sick again for at least three months.

The guidance is based on studies that found that, after three months, there was no evidence of people getting re-infected after recovering, a CDC official said. Longer-term studies are needed to determine how long protection might last, and it's still too soon to say to whether a person who has had COVID-19 and recovered is immune.

The update, which was posted on the CDC's website on Aug. 3, is consistent with CDC's earlier guidance not to retest patients within 90 days of an initial infection, Dr. Annie Luetkemeyer, a professor of medicine at the University of California, San Francisco, said. Although some doctors and patients have raised concerns about the possibility of being reinfected with coronavirus, there have been no confirmed reports of reinfection.

Dr. Joshua Barocas, an assistant professor of medicine at the Boston University School of Medicine, said the CDC’s update “aligns with the idea that it is unlikely that people can be infected within a three month time frame.”