Thread by @ejustin46

𝗧𝗵𝗲 𝗕𝗜𝗚 𝗖𝗛𝗔𝗟𝗟𝗘𝗡𝗚𝗘 𝗼𝗳 "𝗔𝗡𝗧𝗜𝗚𝗘𝗡𝗜𝗖 𝗦𝗜𝗡" !

nature.com/articles/s4146…

2) The study investigated how previous vaccination with mRNA vaccines targeting the original Wuhan strain of SARS-CoV-2 affects the immune response to infection with the Omicron variant.

3) Three groups of individuals were studied: 1) unvaccinated individuals infected with Omicron, 2) individuals vaccinated 3 times who were later infected with Omicron, 3) individuals vaccinated 3 times but uninfected.

4) Vaccination increased plasma antibodies and neutralizing antibodies against Omicron, but it impaired the generation of new antibodies and B cells targeting mutated regions of the Omicron spike protein compared to unvaccinated infected individuals.

5) T cell responses to mutated regions of the Omicron spike protein were similar between vaccinated infected/uninfected individuals and unvaccinated infected individuals, likely due to higher cross-reactivity of T cells.

6) The findings suggest vaccination imprints the immune response and hinders the formation of antibodies and B cells targeting variants that have mutated sufficiently from the original strain.

7) This antigenic imprinting effect of vaccination could lead to a phenomenon called "original antigenic sin", whereby immunity fails to control a highly mutated variant that escapes existing vaccine-induced immunity.

8) The study highlights the importance of developing variant-adapted vaccines that can induce immune responses targeting both conserved and mutated regions of emerging variants.

9) Very interesting comments on this study ...