COVID-19 vaccine study has a warning for people who take common IBD drug

A new study is alerting people who take a common drug for Irritable Bowel Disease (IBD) that their body's response to the first COVID-19 vaccine dose may be lower than expected. The issue was observed in people taking an immune-suppressing drug called infliximab, which is commonly prescribed for IBD.

Vaccines, including the COVID-19 vaccine, work by triggering the patient's own immune system, resulting in the development of antibodies that help protect the individual from an infection caused by the related virus. The level of protection offered by a vaccine depends on the number of antibodies it results in.

According to a new study led by the University of Exeter, people who take the anti-TNF biologic drug infliximab may experience an inadequate immune response after receiving their first COVID-19 dose. That's based on data from hundreds of people treated with infliximab, around a third of whom generated enough antibodies after the first vaccine dose for effective protection.

The number dropped when evaluating people who were taking both it and other immunomodulator drugs, according to the study, with only 125 people out of 537 generating enough antibodies for them to detect on a test. The good news, however, is that participants who'd previously contracted SARS-CoV-2 and developed COVID-19 experienced a 'significantly' higher antibody level, as did people who'd received the second shot.

The news is bittersweet, indicating that people who take this medication should get priority when it comes to the second vaccine — but, ultimately, that the two-dose regimen is effective at protecting them from the virus. The study's co-author Dr. Nick Powell explained:

Although we know that this has been an incredibly difficult time for people with IBD, our research indicates that people treated with infliximab should consider that they are not protected from COVID-19 until they have had both doses of a vaccine and should continue to practice enhanced physical distancing and shielding if appropriate.