Question: I had coffee the other day with a former colleague. He was telling me that his wife had COVID in February 2020 and that as a result, she doesn’t need to get the vaccine. Is she immune to COVID for life?
Answer: Duration of immunity is another area that we’re still learning about. I’ve included more details below, but to sum up, immunity post-infection could be long-lived for many, but not all individuals. Immunity will be greatly enhanced through vaccination, which CDC and other experts recommend. Read on for more details.
When it comes to immunity post-infection, we know that:
- Infection-derived immunity (aka natural immunity) is more heterogeneous than vaccine-derived immunity, varying especially by age and by severity of infection. (see WHO, Q&A of 3/18/21)
- In most people, immunity lasts at least 6-8 months (as long as we have solid longitudinal data), and likely much longer. (see WHO)
- Recent research indicates that long-term immunity to SARS-CoV-2 may persist for years. For example, a paper published in Nature last month found that SARS-CoV-2 infection induces long-lived immune memory residing in bone marrow (home of memory B cells). (for more on this topic, see this commentary published in Nature just yesterday and for a quick refresh on how the immune system works, see Q&A of 5/9/20).
- Even in this study, however, immunity was not consistent across study participants; of those participants who donated bone marrow (n=19), four (4) did not have detectable memory B cells. As the lead study author, Dr. Ellebedy, told the New York Times, “It tells me that even if you got infected, it doesn’t mean that you have a super immune response. The findings reinforce the idea that people who have recovered from Covid-19 should be vaccinated.”
- Among individuals who had been previously infected, vaccination with mRNA vaccines has been shown to further boost immune response.
- CDC recommends that individuals should be vaccinated regardless of whether they already had COVID-19.