On one hand, Long COVID was twice as prevalent in the Delta era than with Omicron variants. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0348954

But receiving a third COVID-19 vaccine dose did not meaningfully reduce 6- or 12-month long COVID incidence compared with completing only a primary series.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0348954

https://www.sciencedirect.com/science/article/abs/pii/S0264410X26004743