Natural immunity vs. vaccination: Which fights off COVID-19 best?

For the millions of people who have had the COVID-19 infection and recovered, questions remain about the level of immunity from the virus and how long that protection could last.

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And the same questions are being posed by the more than 189 million Americans who have been fully vaccinated.

A new study in the journal Science sheds light on the immunity conferred by having the vaccine versus how much protection you have from the disease after you have been vaccinated.

According to the study, a combination of natural immunity with two doses of the mRNA vaccine is likely to produce a strong immune response and may last longer than vaccination alone.

Having the virus and surviving creates immunity against COVID-19, meaning that for a while, your body would recognize the virus if you were to be reinfected and would fight it off.

However, researchers know that some have developed COVID-19 more than once, leading scientists to wonder how long natural immunity from the virus lasts.

According to some researchers, if a person is unvaccinated, reinfection from the virus could happen as soon as three months after contracting the virus. Additionally, scientists do not know how severe or lasting the illness must be to create enough immunity to fight off the virus if the body sees it again.

“Reinfection isn’t really the critical problem for COVID-19. Instead, the most important point is severity of infection. If previous infection protects from serious disease developing, it becomes less important to the individual if they get infected a second time,” Dr. Alexander Edwards, associate professor in biomedical technology at the University of Reading in the United Kingdom told Medical News Today.

“However,” he continued, “for COVID-19, we still don’t know if previous infection will fully protect from severe disease and death for everyone.”

According to studies published in The Lancet Microbe, unvaccinated people can expect immunity against reinfection to last for 3–61 months after contracting the COVID-19 virus.

“The study underscores the importance for the public to understand that immunity from natural infection is not as long lasting as some may perceive, and certainly not lifelong,” Dr. Ajay Sethi, associate professor of population health sciences at the University of Wisconsin-Madison, told Medical News Today.

Sethi was not involved in the research for the study.

The study posted in the Lancet suggests that the best protection for continued immunity in those who have already had a COVID-19 infection is to get a vaccination sometime between three and six months following the infection. Additionally, it is believed that you need only one dose of an mRNA vaccine.

Dr. Monica Gandhi, an infectious disease expert at the University of California, San Francisco and San Francisco General Hospital, told USA Today that natural immunity plus a dose of the vaccine provides the best protection, but only one dose of the vaccine is needed.

“If you’re naturally immune, get one dose,” Gandhi said.