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The Over-Volunteering Prevention System

When you join one of our clinical trials at the Oxford Vaccine Centre, we register your information with The Over-Volunteering Prevention System (TOPS). Find out more about why, and what it means to you as a participant.

TOPS is a database run by the NHS Health Research Authority. It helps stop people from taking part in trials of new medicines too often. All UK studies testing new medicines in healthy volunteers must use TOPS.

TOPS helps us keep you safe. If you take part in trials too close together, the medicines might react with each other in ways we don't expect. Taking too many blood samples could also cause anaemia.

It may not be clear to everyone what we mean by “too often”. In general, we make sure that there is at least a 30 day gap from finishing one study before someone is able to enrol in a new study. Sometimes the gap may need to be a bit longer for safety reasons, it depends on the study and what new medicine you may have taken. TOPS is not there to stop you from taking part again in the future.

If you've taken part in our studies before, we'd welcome you back for future studies when enough time has passed, if they are suitable for you. If you're not sure if enough time has passed, you can always ask us.

TOPS is a database run by the NHS Health Research Authority. It helps stop people from taking part in trials of new medicines too often. All UK studies testing new medicines in healthy volunteers must use TOPS.

TOPS helps us keep you safe. If you take part in trials too close together, the medicines might react with each other in ways we don't expect. Taking too many blood samples could also cause anaemia.

It may not be clear to everyone what we mean by “too often”. In general, we make sure that there is at least a 30 day gap from finishing one study before someone is able to enrol in a new study. Sometimes the gap may need to be a bit longer for safety reasons, it depends on the study and what new medicine you may have taken. TOPS is not there to stop you from taking part again in the future.

If you've taken part in our studies before, we'd welcome you back for future studies when enough time has passed, if they are suitable for you. If you're not sure if enough time has passed, you can always ask us.