While the available COVID-19 shots are still useful, companies are beginning to update their formulas in response to emerging variants. “Whether it turns out to be a false alarm, it would be really good to know if we can actually do this—get a new vaccine rolled out and be ready,” said E. John Wherry of the Perelman School of Medicine.
https://www.usnews.com/news/health-news/articles/2021-12-09/vaccine-makers-racing-to-update-covid-shots-just-in-case U.S. News & World Report