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# FDA Thinking About Vaccine Changes for Variants: Marks
- URL: https://www.fdaweb.com/fda-thinking-about-vaccine-changes-for-variants-marks/
- Published: 2021-02-11T12:00:00.000Z
- Updated: 2026-09-14T16:46:27.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5148645

CBER director **Peter Marks** says FDA is starting to think about how to resequence vaccines to cope with emerging virus variants. Appearing as a guest on an American Medical Association [Webinar](https://www.ama-assn.org/delivering-care/public-health/fda-director-peter-marks-md-phd-discusses-covid-19-vaccine-safety?ref=fdaweb.com), Marks says that for the Pfizer and Moderna mRNA vaccines, it requires only changing a computer program to change the vaccine.

He said FDA is considering what information it would need from companies to feel comfortable with such changes. He said it will not be necessary to do another full clinical trial for efficacy, although a small trial to demonstrate immunogenicity and which variants are being covered would be needed. There also would probably be a streamlined authorization process, he said.

Another question posed to Marks dealt with what doctors should tell their patients about vaccines that demonstrate less efficacy than the Pfizer and Moderna products. He said that a case can be made for vaccines that demonstrate 75%-80% efficacy in a single shot with no special storage conditions as an important tool in the effort to reach national herd immunity. “We need all the tools we can get right now,” Marks said.

He projected that the use of emergency use authorizations for vaccines and therapeutics will continue for some time so that it is not necessary to wait for sufficient data to meet requirements for full authorization.