The 673,676-person Israeli study found that people who recovered from prior SARS-CoV-2 infection and remained unvaccinated were 27 times less likely to experience symptomatic reinfection from the Delta variant when compared to those who had not been infected and received two doses of the Pfizer-BioNTech vaccine.
The study also found that previously infected people who received a single dose of the vaccine received additional protection against the Delta variant.
In a smaller study conducted by Washington University School of Medicine and published in Nature, senior author Ali Ellebedy, PhD, an associate professor of medicine and of molecular microbiology, found antibody-producing cells in the bone marrow of 15 of 19 study subjects 11 months after their first COVID-19 symptoms. "These cells will live and produce antibodies for the rest of people’s lives.
That’s strong evidence for long-lasting immunity. Just a thought.