New research suggests that coronavirus antibodies could remain stable for at least four months after diagnosis and fade much slower than previously reported.
The findings come from a large-scale antibody report published Tuesday involving more than 30,000 people in Iceland. Considered the most comprehensive study of the body's response to COVID-19, experts are hopeful it could lead to immunity through a vaccine.
The new study, conducted by Reykjavik-based deCODE Genetics, analyzed blood samples of 30,576 people and discovered that those who tested positive for the virus possessed antibodies that rose for two months after infection was initially diagnosed and then plateaued, before remaining stable for four months.
Previous studies suggesting that antibodies fade quickly may have only analyzed the first wave of antibodies, 28 days after diagnosis. According to the new study, a second wave of antibodies forms approximately a month or two into infection. This indicates a more stable and long-lasting response.
"Infections and vaccines generate two waves of antibodies: The first wave is generated by early short-lived plasma cells, poised to populate the systemic circulation, but this wave subsides rapidly after resolution of acute infection," scientists Galit Alter and Robert Seder wrote in the commentary published alongside the research. "The second wave is generated by a smaller number of longer-lived plasma cells that provide long-lived immunity."
The research also found that nearly a third of Iceland infections were in people who reported no symptoms. It also discovered that the infection fatality rate was 0.3% — three times as deadly as the seasonal flu.