The level of protection offered by vaccination against Covid-19 is lower for cancer patients than those in the general population, according to the UK Coronavirus Cancer Evaluation Project.

The study, co-led by the Universities of Oxford, Birmingham and Southampton and the UK Health Security Agency (UKHSA), published in Lancet Oncology, is the first time that Covid vaccine effectiveness had been examined in people with cancer on this scale.

The Covid-19 vaccination was effective in most cancer patients, but the level of protection against Covid-19 infection, hospitalisation and death was reduced, it was found.

Three to six months after a second vaccination, the protection offered by the vaccine was found to be reduced by nearly a third in cancer patients compared to people with no active or recent cancer.

The researchers looked at the number of positive Covid-19 tests and subsequent hospitalisations and deaths in a group of 377,194 patients with active or recent cancer. All of the participants had received two doses of Covid-19 vaccine. The results were compared to a control group of people with no active or recent cancer.

The effectiveness of the Covid-19 vaccine was 66% in the group of patients with cancer, compared to 70% in those without cancer. However, this was reduced to 47% three to six months after the second vaccine for cancer patients, compared to 61% in the general population.

The vaccine offered the lowest levels of protection for blood cancer patients, with the vaccine having only 13% effectiveness in patients with lymphoma and 19% effectiveness for leukaemia patients. It was also lowered if a cancer patient had been treated with chemotherapy or radiotherapy in the last twelve months. By three to six months, effectiveness had also waned more when compared with people who did not receive these treatments or were treated more than a year ago.

Professor Peter Johnson, from the University of Southampton, said: ‘This study shows that for some people with cancer, Covid-19 vaccination may give less effective and shorter-lasting protection. This highlights the importance of vaccination booster programmes and rapid access to Covid-19 treatments for people undergoing cancer treatments.’

Current NHS guidance says people who have cancer or have received treatment for certain types of cancer may be at higher risk from Covid-19.