Read this earlier and thought it was interesting. They're testing a third dose of their current vaccine against new strains of COVID that are emerging as well as working on a new dose specifically for the new strain.
https://www.msn.com/en-us/health/medical/pfizer-biontech-studying-third-covid-19-vaccine-dose-to-fight-new-strains/ar-BB1e0tZr?ocid=msedgntp
Moderna seems to be taking the route of creating a new vaccine for the variant strains.
https://www.nbcnews.com/science/science-news/moderna-test-booster-shot-targets-south-african-variant-rcna310
From the first linked article.
"The U.S. Food and Drug Administration said this week it planned to evaluate any vaccine booster shots against variants quickly and wouldn’t require large efficacy trials for authorization"