SARS-CoV-2 vaccination in immunosuppressed patients with inflammatory bowel disease: should our approach change?

Since the publication of the British Society of Gastroenterology (BSG) Inflammatory Bowel Disease (IBD) section position statement on SARS-CoV-2 vaccination,¹ developments concerning vaccine safety have prompted the BSG to review its guidance.

Concerns have arisen with the well-publicised association between the ChAdOx1 nCoV-19 (Oxford/AstraZeneca) vaccine and very rare reports of serious thromboembolic events, including cerebral venous sinus thrombosis, with concurrent thrombocytopenia.² There have been similar reports with the JNJ-78436735 (Johnson & Johnson) vaccine in the USA. This news will be of particular interest to patients with IBD, who are at increased risk of venous thromboembolism, especially during active disease.3, 4

Based on data from over 20 million people having received a first dose of the ChAdOx1 nCoV-19 vaccine, the UK Medicines and Healthcare products Regulatory Agency (MHRA) reports the risk of such thromboembolic events at just over ten per million people vaccinated, with a slightly higher risk in younger individuals.⁵ The MHRA guidance⁵ now states that individuals under 40 years of age, without underlying conditions that put them at higher risk of severe COVID-19 disease, should be offered an alternative COVID-19 vaccine in preference to ChAdOx1 nCoV-19 vaccine, where it will not delay vaccination unduly.

By comparison to the risk of vaccination, the risk that a person will develop a deep venous thrombosis from a single long-haul flight is greater than one in 5000 and the risk of cerebral venous thrombosis in patients with COVID-19 infection is around four times higher than following the ChAdOx1 nCoV-19 vaccine.⁶ The observed thromboembolic events associated with vaccination are thought to be idiosyncratic and mechanistically may be linked to development of antibodies to platelet factor 4. Other than in very specific pro-thrombotic conditions (patients with a history of cerebral venous sinus thrombosis, acquired or hereditary thrombophilia, heparin-induced thrombocytopenia, or antiphospholipid syndrome), the MHRA does not advise avoiding use of the ChAdOx1 nCoV-19 vaccine. We also note that in clinically extremely vulnerable groups and immunosuppressed adult patients with IBD, early vaccination remains the priority, irrespective of age or vaccine type.

We would like to reiterate the firm reassurance issued by the MHRA and other regulatory authorities regarding the ChAdOx1 nCoV-19 vaccine. Furthermore, with data now emerging from the CLARITY IBD study demonstrating attenuated immunogenicity to single dose COVID-19 vaccination in systemically immunosuppressed patients with IBD,⁷ we would like to re-affirm the importance of completing the full vaccination schedule when a second dose is offered, and we strongly recommend that UK health policy makers update their guidance to avoid the extended 12 week dosing regimen in immunosuppressed patients.

JLA reports sponsorship from Vifor Pharma for accommodation/travel to BSG 2019, outside the submitted work. NP reports he has served as a speaker for Allergan, Bristol Myers Squibb, Falk, Ferring, Janssen, Pfizer, Tillotts, and Takeda, and as a consultant and/or an advisory board member for AbbVie, Allergan, Celgene, Bristol Myers Squibb, Ferring, and Vifor Pharma.