Scientists say that if you have natural immunity from a COVID-19 infection and have been fully vaccinated against the virus, there may be no need for a booster shot — yet.

According to The Wall Street Journal, while millions of Americans who are elderly, or at risk, now qualify for the Pfizer vaccine booster shot, it may not be necessary. Research shows that the combination of immunity from the disease coupled with a full course of vaccine, called hybrid immunity, offers adequate protection, even against variants. Recent preliminary studies found that having COVID-19 provides immunity similar to a vaccine dose. These findings consider people who had the disease and then received the vaccine, not the breakthrough cases seen after vaccination.

Dr. Paul Offit, the director of the Vaccine Education Center at Children’s Hospital of Philadelphia and an internationally recognized expert in the fields of virology and immunology, said these people “just won the game.” Offit, a member of the Food and Drug Administration’s vaccine advisory panel, supports boosters for older adults, but not their widespread use at this time. He says that people who already had the virus received the equivalent of a booster shot. The real-world infection teaches the immune system to produce the antibodies, B cells, and T cells that battle future infections.

The new research was conducted in the U.K. by compiling COVID-19 test result data provided by 650,000 people via the ZOE COVID Study app. Analysts found that the combination of real-world infection and the two-dose Pfizer vaccine provided 94% protection up to six months versus 80% protection from the vaccine alone and 65% from only infection, says the WSJ.

Experts say that the findings do not mean that people who had both the infection and the vaccines won’t need a booster in the future and add that those with compromised immune systems or underlying medical conditions should still consider getting a booster shot.

But people with hybrid immunity appear to have superior protection against illness. Those who have been both infected and vaccinated “are likely to be the last group that really needs the booster because they really had three exposures,” said Dr. Akiko Iwasaki, a professor of immunology at Yale University.

Two other studies conducted earlier this year confirmed that even natural infection from the virus provides immunity for at least a year. Coupled with vaccines, the memory B cells were even more robust, according to the New York Post.

“People who were infected and get vaccinated really have a terrific response, a terrific set of antibodies, because they continue to evolve their antibodies,” said Michel C. Nussenzweig, head of the Laboratory of Molecular Immunology at The Rockefeller University, who led one of the studies. “I expect they will last for a long time.”