“Vaccines actually, at least with regard to SARS-CoV-2,
can do better than nature... They are better than the traditional response you get from natural infection,” White House chief medical adviser Dr. Anthony Fauci said during a COVID-19 briefing in May.
Exactly why vaccines appear to generate more robust immunity than natural infection remains unclear, but Dr. Sabra Klein, a virologist and professor of immunology at Johns Hopkins Bloomberg School of Public Health, said infection and vaccination work in different ways.
“The immune system of people who have been infected has been trained to target all these different parts of the virus called antigens. You’d
think that would provide the strongest immunity, but it doesn’t,” Klein said. “The Pfizer or Moderna vaccines target just the spike protein — the part of the virus that is essential for invading cells.
“It’s like a big red button sitting on the surface of the virus. It’s really sticking out there, and it’s what our immune system sees most easily,” she continued. “By focusing on this one big antigen, it’s like you’re making our immune system put blinders on and only be able to see that one piece of the virus.”
In other words, vaccines work to strengthen immune responses gained during natural infection; that’s why health experts advise people who’ve had COVID-19 to still get vaccinated."
Prior infection in patients with COVID-19 was highly protective against reinfection and symptomatic disease. This protection increased over time, suggesting that viral shedding or ongoing immune response may persist beyond 90 days and may not represent true reinfection. As vaccine supply is...
pubmed.ncbi.nlm.nih.gov