Amanda Heidt in The Scientist:
A pair of studies published this week is shedding light on the duration of immunity following COVID-19, showing patients lose their IgG antibodies—the virus-specific, slower-forming antibodies associated with long-term immunity—within weeks or months after recovery. With COVID-19, most people who become infected do produce antibodies, and even small amounts can still neutralize the virus in vitro, according to earlier work. These latest studies could not determine if a lack of antibodies leaves people at risk of reinfection.
One of the studies found that 10 percent of nearly 1,500 COVID-positive patients registered undetectable antibody levels within weeks of first showing symptoms, while the other of 74 patients found they typically lost their antibodies two to three months after recovering from the infection, especially among those who tested positive but were asymptomatic.
In contrast, infections caused by coronavirus cousins such as SARS and MERS result in antibodies that remain in the body for nearly a year, according to The New York Times.
More here.