Thread by @profshanecrotty

Immunity in people who have had COVID-19 and get a vaccine is a fascinating topic. There are really impressive immune responses! I discuss this in Science today, particularly highlighting recent discoveries. 🧵
science.sciencemag.org/content/372/65…

Hybrid vigor can occur when different plant lines are bred together. Something similar happens when natural immunity is combined with vaccine-generated immunity, resulting in 25 to 100 times higher antibody responses, driven by memory B and CD4 T cells.

Conceptualized above as trees of different sizes.
And here's another visualization, a bit more to scale. 😁

The papers highlighted were:

science.sciencemag.org/content/372/65…

science.sciencemag.org/content/372/65…

The published format allowed limited references, and so I am providing a fuller set of references here, as the rest of this thread, since so much work is being done.

“Reported natural immunity protection against any SARS-CoV-2 re-infection ranges from 81-99.8% over 7-8 months (1-3,5) (though a concerning drop was observed in persons > 65 years old in Denmark (4)). Levels of immunity can be placed on a spectrum…”

1.      Antibody Status and Incidence of SARS-CoV-2 Infection in Health Care Workers      New England Journal of Medicine 2020 dx.doi.org/10.1056/nejmoa…

2.     SARS-CoV-2 antibody-positivity protects against reinfection for at least seven months with 95% efficacy  dx.doi.org/10.1016/j.ecli…

3.     SARS-CoV-2 infection rates of antibody-positive compared with antibody-negative health-care workers in England: a large, multicentre, prospective cohort study (SIREN)        dx.doi.org/10.1016/s0140-…

4.      Assessment of protection against reinfection with SARS-CoV-2 among 4 million PCR-tested individuals in Denmark in 2020: a population-level observational study          The Lancet 2021 dx.doi.org/10.1016/s0140-…

5. Switzerland
academic.oup.com/cid/advance-ar…

Some of this discussed in this thread:

https://twitter.com/profshanecrotty/status/1399803472615120898?s=20

Delta variant (first seen in India) protection:
ft.com/content/e71471…

"A substantial frequency of memory B cells encode antibodies that are capable of binding or neutralizing VOCs, and the quality of those memory B cells increases over time." ref also:
dx.doi.org/10.1126/sciimm…

"The evolution of B cells in response to infection, or vaccination, is powered by immunological microanatomical structures called germinal centers, which are T cell-dependent, instructed by T follicular helper (TFH) CD4+ T cells."
dx.doi.org/10.1016/j.immu…

"Antibodies are clearly involved in protection against SARS-CoV-2 reinfection"
      Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection      Nature Medicine 2021 dx.doi.org/10.1038/s41591…

T cell recognition of variants (four):
(A)      CD8+ T cell responses in COVID-19 convalescent individuals target conserved epitopes from multiple prominent SARS-CoV-2 circulating variants          Open Forum Infectious Diseases 2021 dx.doi.org/10.1093/ofid/o…

(B)       SARS-CoV-2 variants of concern partially escape humoral but not T-cell responses in COVID-19 convalescent donors and vaccinees.      Science Immunology 2021 dx.doi.org/10.1126/sciimm…

(C) Negligible impact of SARS-CoV-2 variants on CD4+ and CD8+ T cell reactivity in COVID-19 exposed donors and vaccinees .    bioRxiv 2021 dx.doi.org/10.1101/2021.0…

(D)   Comprehensive analysis of T cell immunodominance and immunoprevalence of SARS-CoV-2 epitopes in COVID-19 cases            dx.doi.org/10.1016/j.xcrm…

Studies showing 1-dose immunization data in previously infected individuals are now numerous. Some key ones were cited in this excellent letter:
doi.org/10.1016/j.ebio…

“previously infected people in some … vaccine studies included both asymptomatic and symptomatic COVID-19 cases. Enhanced vaccine immune responses were observed in both groups, indicating hybrid immunity magnitude is not directly proportional to previous COVID-19 severity." ref:

Binding and Neutralization Antibody Titers After a Single Vaccine Dose in Health Care Workers Previously Infected With SARS-CoV-2          JAMA 2021
dx.doi.org/10.1001/jama.2…

This article is now freely available. I got Science to fix their glitch.

science.sciencemag.org/content/372/65…