Current research shows that people who have been infected with covid-19, the illness caused by the coronavirus, retained immunity that was robust after eight months. That gives researchers a starting point in predicting how long immunity may last after vaccination, [infectious disease expert Lana] Dbeibo explained.
But research also shows people who had more severe cases developed a stronger immune reaction than those with milder forms of the disease. And because vaccine-induced immunity appears to be more similar to natural immunity that is derived from severe covid-19 infections, researchers say they believe people who take a coronavirus vaccine will be protected better than most people with natural immunity, said [immunology professor] David Topham.
All of that said, antibodies will wane.
Experts are still trying to determine how long it will take for antibodies to decrease to the point that they are no longer protective. But once that happens, people will need boosters to remind their immune systems to make more antibodies against the disease, the experts said.
[Chunhuei] Chi, with Oregon State University, said Pfizer, Moderna and others are conducting clinical trials to determine how long a booster shot will extend protective immunity and to determine whether their vaccines can be tailored to combat new variants of the virus.