Experts also caution against intentionally trying to infect as a way to gain hybrid immunity. “I am really concerned that people are intentionally becoming infected so they can get to this ‘new normal’,” said Dr. Celine Gunder, an infectious disease specialist at Bellevue Hospital Center. The virus is unpredictable, and even young people can get very sick. She said: “Something could go wrong, and they could end up in the hospital.” Plus, it’s impossible to know who might have Covid long after infection.
How does hybrid immunity protect you?
Boosting immunity to natural infections may be akin to getting a fourth dose of the vaccine, said Dr. Peter Chen Hong, an infectious disease expert at the University of California, San Francisco. Hybrid immunity may also occur if you become infected before vaccination or boosters.
Here’s why. The first time you are vaccinated or infected with a virus, it takes some time for your immune system to respond. But the immune system has a long memory. It reacts faster and increases more antibodies the next time it detects a virus. The effect appears to be more pronounced in people who have been vaccinated and infected.
A recent study showed that vaccinated health care workers with penetrating infection had significantly higher levels of antibodies compared to a vaccinated control group that did not have a natural infection. Although the study was conducted before the Omicron wave, the results suggest a significantly elevated level of protection after infection, said Fikadu Tavis, an immunologist at Oregon Health & Science University who helped conduct the research.
said Anita Gupta, assistant professor of anesthesiology and critical care medicine at Johns Hopkins University School of Medicine. “When some of the short-lived immune cells are gone, those memory B cells will last for some time.”
But here’s the bad news: Exactly how much extra protection you get and how long it lasts will vary by individual, said Akiko Iwasaki, an immunologist at Yale University. A person who is immunocompromised, older, or at high risk of severe disease is likely to produce fewer antibodies than a healthy young person, and their antibody levels may decline more rapidly.
It is also not clear whether disease severity affects the level of mixed protection. Dr Iwasaki said a person with severe symptoms may have been exposed to a greater amount of the virus, which could lead to more antibodies and therefore more protection. A person who has not shown symptoms may not have a strong immune response to the virus and may be more susceptible to infection again.