If you’ve had COVID-19, do you need the vaccine?

While some people who have recovered from COVID-19 may have developed antibodies, experts say the COVID-19 vaccine is still the best choice for protection against the virus, even after recovering from previous infection.

For those who’ve had COVID-19, the level of the immunity developed after recovering from the infection depends on several factors, including age, overall health and how serious the infection was.

“A recent review by Washington University School of Medicine concluded that following infection some people can have natural immunity for at least a year, but not everybody shows this response,” said BJC chief quality officer Hilary Babcock, MD, a Washington University infectious diseases specialist.

The vaccine, Dr. Babcock says, offers more consistent and longer-lasting protection than infection. For those who have recovered from a previous COVID-19 infection, getting vaccinated provides a boost in antibody levels and immunity, which may also provide better protection against future variants that may develop.

“The added protection generated by your immune system in response to the vaccine strengthens the response from the infection — and makes it last longer as well, providing additional protection,” Dr. Babcock said. “The vaccine is like a booster for people who have already had COVID-19.”

Without that added protection from the vaccine, Dr. Babcock said, antibodies from COVID-19 infection will decrease over time, leaving those who have had the disease at risk of reinfection. And while vaccinated people can occasionally get infected with COVID-19, their risk of infection is much lower than for those who are unvaccinated, and their risk of getting very ill or ending up in the hospital is also much lower.

A recent study by the U.S. Centers for Disease Control and Prevention (CDC) found that people who were unvaccinated and had a recent COVID-19 infection were five times more likely to experience another COVID-19 infection than people who had not had a prior infection and were fully vaccinated against COVID-19.

The CDC noted that the data demonstrate vaccination can provide a more robust and more consistent level of immunity than infection alone for at least six months, which can protect people from hospitalization for COVID-19.

“We now have additional evidence that reaffirms the importance of COVID-19 vaccines, even if you have had prior infection,” said CDC director Rochelle Walensky, MD. “This study adds more to the body of knowledge demonstrating the protection of vaccines against severe disease from COVID-19. The best way to stop COVID-19, including the emergence of variants, is with widespread COVID-19 vaccination and with disease prevention actions such as mask-wearing, washing hands often, physical distancing and staying home when sick.”

The study examined more than 7,000 people across 187 hospitals in nine states. The data showed that among adults hospitalized with COVID-19 symptoms, unvaccinated people who’d had a COVID-19 infection within the last three to six months were more than five times more likely to be diagnosed with COVID-19 than those who were fully vaccinated with mRNA (Pfizer or Moderna) COVID-19 vaccines in that same time period.

Vaccinated people are also less likely than those who are unvaccinated to spread the virus to others, if they do become infected. “The amount of virus found in the nose of vaccinated people who do develop an infection is lower than in the unvaccinated, and the number of days the virus can be detected in the nose of infected vaccinated people is shorter,” Dr. Babcock said. “The risk of transmission of the virus to others is therefore lower than from unvaccinated infected people.

“This decreased risk has been confirmed with studies showing decreased household COVID-19 transmission from vaccinated people who get infected compared to unvaccinated infected people.”

Dr. Babcock added that the vaccines are not only effective at preventing infection, serious illness and hospitalization, and reducing the spread of the virus — they’re also safe.

“These vaccines have met all of the required safety and effectiveness criteria, similar to other vaccines we all get,” she said. “And getting the vaccine is a far safer way to gain immunity against COVID-19 than by trying to achieve immunity through infection with the virus. The vaccines truly are our best defense against COVID-19.”

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