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# Clinical Trials Guide Amended with EUA Product Considerations
- URL: https://www.fdaweb.com/clinical-trials-guide-amended-with-eua-product-considerations/
- Published: 2021-01-27T12:00:00.000Z
- Updated: 2026-09-14T16:44:16.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5148543

FDA has amended its guidance on [*Conduct of Clinical Trials of Medical Products During the COVID-19 Public Health Emergency*](https://u7061146.ct.sendgrid.net/ls/click?upn=4tNED-2FM8iDZJQyQ53jATUURzbOiTj4rjf8eQ-2FYEfOQ5THSul0bFGo4FhyR4b-2BPkN6tXfIb03jEQfD9nEWL3f97KHcaOOQ7u-2FaCjWJGOMNseOmO8gEl6SYs-2FDXcI1vvll98MimjFL8CeBXKlTveebYHU3ufmS6atjXDwIIroZjnTZeVR4JwBsUWoLtJBvTXObo5FDyzT3QOuYxjgG0e09etb5VUauCka5RIIUYvOZNFXs-2FyJXfP4OFcqGdA3xIt0dtX-2FF4wiaRbu1O5ejblouxxXPqOHCHhXCb96KCz6AIV77SWxawbtKk9ROh18ZlGRzS7TXQruE3Fq-2FqQCqGmjcCGUsIYlOONhTgKXuS4ccyIqjLdxjJ1mlh1rI9fDJ9tpzfhkZSkfWAJtUfNTZ5DLHw4jfu5Yv0UA-2BNIWsVZwJ2W485OxQesHKyV6Wzq45-2BYz32KlEtv2lX7vs4sDX-2BR1KrF8CBPAdC9PDXQ0XvEGog6D23KZeSQiouwtUgv8FGqWE63T3LUcdYvZvRWbnT9gHWBlse2DZLw0kV2-2BggNeSdBJo7axubqwZ4rg-2BhshnbpX7UOJM-2BYr1EA8Zm9EqR9Fussc6ojYO5Hk5qdSyVFznYzF1pYIJg0kQR0citUpgNSVlLA6QVdi-2FXaukH20g4s4MCLMvpmxijdVWHmWAl3HeNAc-3D79yh%5Ff0D7hj0BJ4b-2F7NuVqzPDs7FGiq8VLIwAX0sPSotqoLLneMdQF3zCTCLlHvBJvyfh-2BZPeNK3mQsImA4zeHYIAjN-2Bi7kPv8tx6CtGtcsK3dABbmil839j-2BGjV2A-2BZqmTrGdtED4EvxtvAtEsRhlkQ-2FnrmJFFxzU3VS4z3jZ90ntvUDRrZSP8cMp6tW3AXnDlzxsl7AZ5RXTCMs8gb4ODfRwtdfu9Fl0Pn94vqGfUG9bJAhsMAUGpKl7mSL-2B2vR7WdY9kxv91ZLManXBUFlUjyiRGwPstsS3G0RiSfolBxzSF-2FcyA-2BxbyKCGIAF8l2k9C-2BomaitP0yCUvKzClu2ud-2FA8-2FkhQMSOMkFFcH3TJUzhxl8iwN8B7h1xTrIn-2FE5G-2FA4w&ref=fdaweb.com) to add content to the question-and-answer appendix about including patients who have received a Covid-19 vaccine or other emergency-use authorization (EUA) products in clinical trials. FDA says the information may be relevant when sponsors are considering eligibility criteria that exclude patients from enrolling in clinical trials if they have received certain medical products. The guidance is intended to address challenges in conducting clinical trials that may arise from isolation practices, site closures, travel limitations, interruptions to the supply chain for the investigational product, or other considerations if site personnel or clinical trial participants become infected with Covid-19.

The updated guidance notes that certain clinical trial protocols have an exclusion criterion for patients taking/using an investigational medical product. “When a medical product is being used under an EUA, it is an authorized (though not an approved or cleared) medical product for use in clinical care that has met the statutory criteria under section 564 of the FD&C Act,” the agency says. “The product is not being studied under an IND or IDE when used pursuant to an EUA, and FDA therefore does not consider receipt under an EUA as receipt of an investigational product. In contrast, when the same product is used in a clinical investigation under an IND or IDE, the product’s safety and/or effectiveness is being studied for investigational uses, and FDA would consider receipt in this situation to be receipt of an investigational product.”

However, the guidance says that when a clinical investigation is designed, there may be valid scientific reasons to have an exclusion (and even a discontinuation) criterion for a medical product — a monoclonal antibody or vaccine, for example — whether that product was used under an EUA or not. “These scientific reasons may include risks to an individual if they enroll or continue to participate in a clinical trial after receiving (or having received) the excluded product, or the potential impact of the use of the excluded product on trial objectives, such as confounding the determination of effectiveness of the product under investigation,” it says.