In a Feb. 17 update to its guidance on managing clinical trials during the COVID-19 pandemic, the U.K.’s Medicines and Healthcare Products Regulatory Agency (MHRA) said all sponsors of ongoing clinical trials for indications other than treatment or prevention of COVID-19 are required to evaluate the impact a COVID-19 vaccine may have on the trial.

If the risk assessment shows that a COVID-19 vaccine given to a trial subject would be considered a simple concomitant medication with no interaction that would require advice on timing of the vaccine or other trial aspects, then the sponsor should inform the MHRA of that assessment in a nonsubstantial update in its next substantial amendment.

But if the risk assessment points to potential issues that need to be mitigated, the sponsor must submit a substantial amendment. Such may be the case in trials with immunosuppressive elements or immune-related mechanisms, infection aspects or in a high-risk population, the MHRA said.

For new trials, the agency encourages sponsors to address potential COVID-19 vaccination in their protocol and include appropriate flexibilities to avoid the need to submit substantial amendments later.

The update lists several points sponsors should consider in the risk-assessment of vaccinations, including the impact on blinded trials, recordkeeping, potential interactions between the vaccine and the study drug, and safety reporting.