An important trial will test how to boost Covid jab protection in vulnerable patients whose immune systems are weakened by drugs they need for other health conditions, BBC reported.
About 1.3 million people in the UK are on methotrexate for conditions such as rheumatoid arthritis and psoriasis.
The team will check if a two-week drug holiday timed to vaccination will help.
A previous study from Korea showed that a fortnight's break from methotrexate immediately after the flu vaccine increased the patients' immune response to that jab.
The University of Nottingham researchers, working with other universities and hospitals, will recruit 560 methotrexate patients, and half of them will try the two-week break when they are due to have their third, or booster, Covid jab.
Although the Vroom study will take one to two years to complete, scientists hope it will provide confidence for some of the most vulnerable patients at risk from Covid.
Prof Abhishek Abhishek, the chief investigator, said people on immunosuppressants faced being more at risk of getting ill if they catch Covid, as well as potentially being less able to mount the strongest possible immune response to vaccines against the virus.