If a prospective subject recently received a COVID-19 vaccination, is there a recommended “washout” period prior to enrollment in another clinical trial?
– Regulatory Affairs Professional, CRO


There is no one size fits all answer to this question. The decision to establish a “washout period” as an eligibility criterion for a study is a medical decision and depends on many factors including the subject population, the investigational product being studied, and the duration of the study.

For example, if the study involves an investigational agent that may cause adverse events within days of administration, it would make sense to exclude from the study those individuals who were recently vaccinated against COVID-19. The washout period could be based on what is currently known about the type, onset and duration of COVID-19 vaccine related adverse events.


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