This is among the first of the large-scale studies of vaccine roll-out in the real-world setting of immune-suppressed people – in this case, people with IBD taking the common anti-TNF drug, Infliximab.  It is also used by many with arthritis.  We’re used to the message that, on average, for most people, even one dose of vaccine offers considerable protection against symptomatic or severe infection.  However, in the real-world, people are complex.  The answer here is that around a third of patients with Inflammatory Bowel Disease who are taking infliximab don’t develop antibodies after one vaccine dose at a level likely to be protective.  While it’s great that so many people in the UK have received one vaccine dose, examples such as this are a reminder not to be complacent and to press on to the second vaccine dose.  Many other studies are in the pipeline to consider other groups of immune suppressed patients and vaccine responses.