There has been a study a month ago looking into B/T cell response for the covid vaccines. https://www.science.org/doi/10.1126/science.abm0829 Article is hypertechnical, fortunately there is a more approachable twitter thread from the first author, https://twitter.com/rishirajgoel/status/1448711946010710023. The HN thread is pretty bare, and I remember a more active conversation, so perhaps either that happened on a dupe, or there is another article along those lines. https://news.ycombinator.com/item?id=28881923

"To summarize:

- Antibodies decrease but memory B/T cells are stable for ≥6 mo

- Immune memory is still effective vs. variants

- "Boosting" from memory = significant (but temporary) increase in antibodies w/ less impact on already durable memory cells"