Drug to treat IBD may blunt Covid immunity after virus or first vaccine, study shows

Professor Shaji Sebastian

A Hull hospital team has made a major contribution to research indicating that patients with inflammatory bowel disease on a commonly used medication may not mount adequate immunity and immune memory if they contract Covid-19, or following their first dose of the vaccine.

Professor Shaji Sebastian and his team at Hull University Teaching Hospitals NHS Trust co-led the CLARITY study of 7,200 patients with Crohn’s disease and ulcerative colitis from 92 hospitals in the country.

The study discovered fewer than half who receive the drug Infliximab had detectable antibodies after catching the virus, suggesting the treatment had blunted the immune response to infection.

In a second paper, currently in review, they describe the same effect following vaccination for Covid-19, particularly if patients were being treated with Infliximab as well as an immunosuppressant such as azathioprine.

Professor Sebastian, the lead consultant in inflammatory bowel disease (IBD), said CLARITY was the first study involving these clinically vulnerable patients which has raised some concern about their immune response.

He said: “The good news is that almost all patients had a boost in immune response after the second dose or after the first dose if they had been infected with Covid-19 before.

“Overall, it appears that these patients need more than one challenge – either with two doses of vaccines or at least one dose in those who had previous infection.”

He said it was important that people with IBD continued their medication and took up the offer of vaccine as the evidence suggested their outcomes if they caught the virus were better.

“We and others across the world are now looking at whether further booster doses are required in some patients by measuring their antibody levels over time after vaccination and specific immune cell functions,” said Professor Sebastian.

“I am grateful for our patients who are participating in this ongoing study, and also the excellent integrated IBD team, in particular research nurses Alison Talbot, Sally Myers, and Jack Turnbull.”

The Hull team recruited 330 patients with IBD; the most recruited by any of the hospitals taking part in the study led by the Royal Devon and Exeter NHS Foundation Trust and the University of Exeter Medical School.

The study was also supported by Crohn’s and Colitis UK and the UK National Institute for Health Research.

Around half a million people in the UK live with IBD and many have been shielding since the start of the pandemic.

Sarah Sleet, chief executive officer at Crohn’s and Colitis UK, said: “The CLARITY results are an important first step in helping us understand how different medicines for Crohn’s and Colitis affect a person’s response to coronavirus. 

“At this stage, the key message is people with Crohn’s and Colitis should keep taking their medication to stay well and take the vaccine when offered. But we also need research like this to continue.”