Why get vaccinated after COVID infection?

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More than 35 million Americans have been infected with COVID, and some are wondering: Do I still need to get vaccinated if I’ve already had the virus?

The short answer is: Absolutely.

“This is a common question from patients who have had COVID and are wondering if they still need to get the shot once they’ve been infected,” said Dr. Simone Wildes, infectious disease expert at South Shore Health. “I would definitely say you still need to get the vaccine, because based on what we know, it provides greater protection than you get from being infected.”

Scientists point to two big reasons for that: a more robust immune response, and better protection against new variants.

A stronger immune response

When you’re vaccinated or infected with COVID, your immune system springs into action, producing “T cells” that help recognize and kill the virus, antibodies that fight it off, and “B cells” that make new antibodies. 

The immune response is stronger for the vaccinated – producing 10 times the level of antibodies – than in those who were infected with the virus, researchers have found. 

That means if you’re exposed to the coronavirus again, your body will be better equipped to fight it off if you’ve had the shot. 

One recent study found unvaccinated people are more than twice as likely to be reinfected with COVID-19 as those who were fully vaccinated after initially contracting the virus, suggesting that getting vaccinated provides additional protection.

“If you have had COVID-19 before, please still get vaccinated,” said CDC Director Dr. Rochelle Walensky. “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.”

Scientists are still working to determine why COVID vaccination produces that super immune response. There are some theories: For instance, NIH Director Dr. Francis Collins notes that natural infection usually only exposes the body to the virus in the nose and throat. 

“The vaccine, on the other hand, is delivered to muscle, where the immune system may have an even better chance of seeing it and responding vigorously,” Collins wrote recently.

Protection from variants

Viruses tend to evolve so they can keep infecting the same people over and over– for instance, it’s not unusual to catch the common cold repeatedly as the virus mutates each year. The coronavirus is evolving too, with highly transmissible new variants emerging.

People infected early in the pandemic may be immune to an early strain, while being vulnerable to some of the new variants, clinicians warn. Luckily, COVID-19 vaccines are  proving highly effective at preventing severe illness from the new mutations, including the Delta variant.

New studies suggest that the vaccines are better at spurring the body to train B cells to recognize new mutations and that the antibodies generated in response to vaccination are more effective against new variants too.

When to get the shot

Talk to your primary care provider or a nurse at a vaccination site. Generally, those who have contracted COVID-19 should wait 90 days before getting vaccinated to avoid uncomfortable side effects, Wildes said. 

“It makes sense when you think about it: If you already have antibodies, and you get exposed, then your body is going to respond more aggressively, especially if you get the shot close to the time of infection,” Wildes said. “For that reason, we tell you wait for 90 days.”

Side effects are generally mild and rarely last more than three days, she said. Rest, fluids and acetaminophen can be helpful if you experience any discomfort after the shot.

And it’s well worth the discomfort. 

“Our best hope of controlling this pandemic is to get vaccinated,” Wildes said. 

Vaccines are free and widely available to anyone 12 or over. To make an appointment or find a walk-up site, visit https://vaxfinder.mass.gov/.

Every shot saves lives, and limits the chances of new, even more dangerous variants appearing.