Large antibody study offers hope for virus vaccine efforts
Antibodies that people make to fight the new coronavirus last for at least four months after diagnosis and do not fade quickly as some earlier reports suggested, scientists have found.
Tuesday's report, from tests on more than 30,000 people in Iceland, is the most extensive work yet on the immune system's response to the virus over time, and is good news for efforts to develop vaccines.
If a vaccine can spur production of long-lasting antibodies as natural infection seems to do, it gives hope that "immunity to this unpredictable and highly contagious virus may not be fleeting," scientists from Harvard University and the U.S. National Institutes of Health wrote in a have been reinfected with the coronavirus months after their first bout.
The new study does not establish how much or which type of antibody confers immunity or protection—that remains unknown.
The study also found:
— Testing through the bits-of-virus method that's commonly done in community settings missed nearly half of people who were found to have had the virus by blood antibody testing. That means the blood tests are far more reliable and better for tracking spread of the disease in a region and for guiding decisions and returning to work or school, researchers say.
— Nearly a third of infections were in people who reported no symptoms.
— Nearly 1% of Iceland's population was infected in this first wave of the pandemic, meaning the other 99% are still vulnerable to the virus.
— The infection fatality rate was 0.3%. That's about three times the fatality rate of seasonal flu and in keeping with some other more recent estimates, said Dr. Derek Angus, critical care chief at the University of Pittsburgh Medical Center.
Although many studies have been reporting death rates based on specific groups such as hospitalized patients, the rate of death among all infected with the coronavirus has been unknown.
The news that natural antibodies don't quickly disappear "will be encouraging for people working on vaccines," Angus said.
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