Why You Might Need A Vaccine Even If You've Already Had COVID-19

If you've already recovered from COVID-19, you might think the coronavirus vaccine isn't for you. But because any natural immunity that COVID-19 provides is so variable, anyone who has already been infected should get the vaccine anyway, health officials say. It's difficult to predict who will survive an infection unscathed, making relying on the strength of your immune response "a very bad decision," as Jennifer Gommerman, an immunologist at the University of Toronto, told The New York Times.

Scientists are still learning much about the coronavirus, including what protection a previous bout with the virus provides. Antibodies, or proteins that battle bacteria and viruses, can fluctuate from person to person (via The Miami Herald). One non-peer reviewed study published last month found that recovered coronavirus patients still had immune cells eight months later; however, other experts suggest that this natural immunity lasts only about four months.

The Centers for Disease Control and Prevention said it won't know more about such natural immunity without more research. In addition, a person who has already recovered from the virus can become infected again. "Due to the severe health risks associated with COVID-19 and the fact that re-infection with COVID-19 is possible, people may be advised to get a COVID-19 vaccine even if they have been sick with COVID-19 before," the CDC says.

COVID-19 affects people differently, so relying on illness for natural immunity isn't wise, doctors say

There is no way to know how COVID-19 will affect you, even if you aren't elderly or have medical conditions that put you at increased risk of severe complications, the CDC says. A vaccination protects your family and others around you from getting sick, as well as prevents you from having to get sick to create that immune response (via the CDC).

Vaccines from Pfizer/BioNTech and Moderna are the first in the United States seeking authorization. The manufacturers did not test the vaccines in people who knew they had been infected with COVID-19 or were sick with symptoms at the time (via The Miami Herald). But up to 10 percent of participants in both vaccine trials had unknowingly been infected before receiving the vaccine, Dr. Moncef Slaoui, the chief science adviser for Operation Warp Speed, has said (via NBC News).

If you have some sort of natural immunity after rebounding from COVID-19, you likely don't have to rush to get the vaccine; but it won't hurt to get it. "It's clear that one is less problematic for the body to recover from than the other — there's more risk with natural infection," Dr. Marion Pepper, an immunologist at the University of Washington in Seattle, told The New York Times. "There's nothing deleterious about getting a boost to an immune response that you've had before. You could get an actually even better immune response by boosting whatever immunity you had from the first infection by a vaccine."