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If You've Had COVID-19, Do You Really Need The Vaccine?

April 22, 2021

If you've had COVID-19, you'll still need the vaccine for full protection from the virus. But it's looking more and more as if your previous infection, and your body's robust immune response, might have left behind a significant level of immunity -- though, unfortunately, not quite enough to skip the vaccine. Here's some evidence:

  • In a study of 1,000 staff members of the Cedars-Sinai Medical Center in Los Angeles, participants who had recovered from COVID-19 built up an immune response after their first dose of vaccine comparable to their never-infected co-workers who had received two doses.
  • In another study of the immune response of 188 infected people, 90 percent of the participants still had a significant immune response up to eight months later. That protection would likely last much longer, according to researchers at the La Jolla (Calif.) Institute for Immunology who published the results. Yet 10 percent did not produce enough protective antibodies, memory B cells or helper or killer T cells -- all critical components of immunity.
  • The level of antibodies in COVID-19 survivors produced after one dose of vaccine equaled or exceeded the level in uninfected people after two doses, according to a study at the Icahn School of Medicine at Mount Sinai in New York.
  • Healthcare workers previously infected with COVID-19 had a much higher antibody response than those not previously infected after one vaccine dose in a study at the University of Maryland School of Medicine.
These studies, though encouraging, do not offer enough data for the Centers for Disease Control and Prevention to change its current recommendation that those previously infected should still receive two doses of the Pfizer-BioNTech or Moderna vaccine. (The CDC, in a March report, suggested both of those vaccines appeared to be 90 percent effective in a real-world setting in preventing COVID-19.) "The vaccine reduces all the high-risk and high-mortality issues," says Dr. Anuj Vohra, Medical Director of Emergency Services at Charlotte Hungerford Hospital in Torrington, "and puts us more into the flu-like illness category, where it's safe. . . . [The vaccine] is here to save our lives and help prevent the spread to others we care about and love. So it's very important to get the vaccine."