Best views, weather, etc. How to test them 👓 SC, Ala. sites look back Betty Ford honored
Coronavirus COVID-19

Natural infection isn't enough to protect against COVID-19, experts say. You still need a vaccine.

As concerned friends and family members try to convince loved ones to get vaccinated, many are met with the argument: "I already got COVID, so I can't get it again."

Health experts say that just isn't true. 

Although antibodies from natural infection may provide some protection against the virus, evidence shows nothing protects against COVID-19 better than vaccines. 

People who have recovered from COVID-19 should get vaccinated to reduce their risk of reinfection, which will prevent transmission and suppress the opportunity for more variants – like the highly contagious delta – to emerge.  

“Natural infection will cause your immune system to make many types of antibodies and immune response to all parts of the virus, but only a small fraction of that response is actually protective,” said Nicole Iovine, chief hospital epidemiologist at University of Florida Health in Gainesville. “When you get the vaccine, the entire response is targeted to the virus's spike protein.” 

A study published Friday by the Centers for Disease Control and Prevention found unvaccinated people who have had COVID-19 are more than twice as likely to be reinfected with the virus compared with people who were fully vaccinated after contracting the virus.

The study included hundreds of Kentucky residents with previous COVID-19 infections from May through June. It showed those who were unvaccinated were 2.34 times more likely to be reinfected compared with those who were fully vaccinated.

“If you have had COVID-19 before, please still get vaccinated,” CDC Director Rochelle Walensky said in a statement. “This study shows you are twice as likely to get infected again if you are unvaccinated. Getting the vaccine is the best way to protect yourself and others around you, especially as the more contagious delta variant spreads around the country.”

Anyone can be at risk for reinfection, health experts said, regardless of age or health status.

'A surge of straight stupidity':The vaccinated are angry. That's understandable but unproductive, health experts say

Will COVID-19 vaccine booster shots be needed? It's likely, experts say, but the immunocompromised should be prioritized.

A study in April published in The Lancet Respiratory Medicine found multiple COVID-19 reinfections in the U.S. Marines Corps, a population considered to be the picture of health. Among the 189 Marines who were infected from May to November 2020, 10% tested positive again.

People reinfected with the virus are more likely to be asymptomatic, which increases the chances of spread, said Michael Grosso, chief medical officer and chair of pediatrics at Northwell Health’s Huntington Hospital in Long Island, New York.

“Individuals who have partial immunity, and therefore susceptible to asymptomatic infection, absolutely place people around them at risk because they don’t know they’re ill, and we know now that they can transmit COVID under those conditions,” he said.

Those with asymptomatic infection can unknowingly expose friends or loved ones who may be older or have weakened immune systems, health experts said, putting them at risk of infection if they’re vaccinated, or worse, at risk of severe disease and death if they’re unvaccinated.

Although most people present milder symptoms during their second bout of COVID-19, Iovine said she's seen a fair share of hospitalizations. 

A 25-year-old man in Nevada was the first reported case of COVID-19 reinfection in October 2020, according to a case study published in The Lancet Infectious Diseases. Researchers said his second go-around was “symptomatically more severe than the first.”

Spreading the disease gives the virus more opportunity to mutate, heath experts said, allowing more variants to emerge. According to the CDC, the delta variant accounts for more than 90% of sequenced cases in the USA. 

“With this delta variant, you want to have the odds in your favor,” Iovine said. “You don’t want to leave yourself with excess risk, and that’s where vaccination is going to give you that extra layer of protection that natural infection cannot.”

Contributing: Christine Fernando

Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.

Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input.

Featured Weekly Ad