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The CIRCUIT Study

Comparing Immunisation-Boosting Regimens for COVID-19 Upon Initiation of immunosuppressive Therapies Study

The challenge

We know that patients on moderate to severe forms of immunosuppressive therapy can have less that optimal responses to COVID-19 vaccine boosters. Few studies have investigated the best time to give vaccine boosters in people facing new immunosuppression, for example as part of treatment for haematological malignancies or autoimmune/inflammatory conditions.

The project

The CIRCUIT Study is a Randomised Control Trial (RCT) of people with haematological malignancies or autoimmune/inflammatory condition commencing immunosuppressive therapy for the first time. Study participants will be randomised to receive a COVID-19 booster vaccine either prior to the onset of immunosuppression OR 6 months-post immunosuppression, when the most intensive phase of therapy is complete. A diptheria-tetanus booster vaccine will be studies as a comparator booster vaccine.

The method

The CIRCUIT Study involves a collaborative research network, with participants being invited to participate from Blacktown, Westmead, Concord, St Vincent's Hospital and Royal Prince Alfred Hospitals.

The results

The CIRCUIT Study will measure the COVID-19 booster vaccine response using a live-virus neutralisation assay at timepoints over a one-year period. At the end of the study period, these measurements will determine if greater protection from COVID-19 disease is provided by providing the booster vaccine just prior to immunosuppression OR if there is higher protection by providing the booster vaccine 6 months after the onset of immunosuppression. This question has not been well answered to-date.

The impact

The CIRCUIT Study will provide important information on vaccine booster timing around the commencement of moderate to severe immunosuppression. This will be relevant to COVID-19 vaccines but also to more traditional forms of vaccine e.g. the diptheria-tetanus vaccine. The ultimate goal of the CIRCUIT Study is to provide a rationale evidence base to inform future national vaccination guidelines for at-risk groups.

Project collaborators