Experts consider ulcerative colitis an autoimmune disease. An overactive immune response causes the immune system to attack healthy tissue in the gut, leading to inflammation of the large intestine.

Some medications people with ulcerative colitis (UC) take also compromise the immune system. However, this does not necessarily mean a person with ulcerative colitis has a higher risk of infection, including with the virus that causes COVID-19.

In this article, we look at the link between the immune system and ulcerative colitis, whether ulcerative colitis increases the risk of infection, and how treatments work to manage ulcerative colitis.

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According to the Benaroya Research Institute, UC is an autoimmune disease.

An autoimmune disease happens when a person’s immune system becomes overactive and attacks their healthy tissue.

In UC, the immune system attacks the intestines, causing inflammation in the large intestine.

See a list of autoimmune conditions here.

If a person does not manage their condition correctly, UC may lower their immune system’s overall function. Excessive immune activity in the gut could mean less immune activity in the rest of the body.

The following table shows a list of immunosuppressive drugs that can treat IBD, as well as drugs that do not suppress the immune system:

Immunosuppressant treatment for IBDIBD treatments that do not suppress the immune system
Steroids: Prednisone and budesonide5-aminosalicylates: Mesalamine, balsalazide, olsalazine, sulfasalazine
Immunomodulators: Azathioprine, 6-mercaptopurine, methotrexateAntibiotics: Ciprofloxacin, metronidazole
Anti-TNF: Infliximab, adalimumab, golimumab, certolizumab pegolDietary interventions: Elemental diet
Anti-IL12/23: Ustekinumab
Anti-integrin: Vedolizumab, natalizumab
JAK inhibitor: Tofacitinib

Learn more about biologics for ulcerative colitis here.

According to a 2021 review, the current evidence suggests people with inflammatory bowel disease (IBD), which includes UC and Crohn’s disease, are not at higher risk of COVID-19 than the general population.

Immunomodulators and biologics are all unlikely to raise a person’s risk of infection.

The American College of Gastroenterology adds that most people taking standard IBD therapies do not have a higher risk of getting COVID-19. They listed the following statements that a person with IBD may find useful regarding COVID-19:

  • Researchers believe that if a person keeps their IBD in remission, it is protective against COVID-19.
  • If a person manages their IBD successfully and does not require steroids or hospitalization, it can put less strain on the existing supply of medical resources.
  • A person should keep taking their IBD medications as a doctor has prescribed.
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Learn about keeping ulcerative colitis in remission here.

A 2021 review found that treatments for IBD did not increase the risks of COVID-19 complications, except for people taking aminosalicylates (5-ASA) and steroids.

In people with IBD who tested positive for COVID-19, 27% of people required treatment in a hospital, and mortality rates were less than 5%.

Negative outcomes were higher in people with UC than Crohn’s disease. This may be because people with UC were more likely to be older and more likely to be taking 5-ASA than those with Crohn’s disease.

Researchers also found that taking biologics reduced negative outcomes.

Learn about the effects of COVID-19 on the body here.

Two of the current COVID-19 vaccines available in the United States are mRNA vaccines. According to the Crohn’s and Colitis Foundation, mRNA vaccines:

  • cannot cause COVID-19, as they do not contain the live virus which causes COVID-19
  • do not affect DNA in any way
  • cannot cause or worsen IBD

In a position statement on COVID-19 vaccines, the Crohn’s and Colitis Foundation states:

  • non-live vaccines are safe for people with IBD, no matter what type of IBD treatment they receive
  • certain type of immune-modifying medications may cause a reduction in vaccine immune response, but this should not be a reason for delaying vaccination
  • if people are taking systemic corticosteroids, they can talk to their healthcare provider about a possible decrease in COVID-19 vaccine effectiveness
  • current FDA-approved vaccines are safe for people with IBD who are pregnant, planning to become pregnant, or are lactating

The foundation encourages people with IBD to discuss any concerns about getting a COVID-19 vaccine with their healthcare provider, and to decide whether they should receive the vaccine based on their individual case.

Learn about the different COVID-19 vaccines and what they do here.

In general, a person seeking to reduce their risk of exposure to the virus that causes COVID-19 should:

  • Avoid non-essential travel
  • Discuss with their doctor whether appointments are necessary at this time
  • Discuss the possibility of virtual, telehealth appointments with their doctor

A person should also follow the CDC guidelines relevant to their situation:

Learn more tips to prevent coronavirus transmission here.

Keeping symptoms of UC in remission can be protective against infection with the virus that causes COVID-19. Therefore, it is important a person knows how to manage their condition. A doctor can provide the most accurate and individualized information. Some treatment methods a doctor may recommend could include:


  • Aminosalicylates: These medications target the lining of the gastrointestinal tract to reduce inflammation. They are effective for the treatment of mild to moderate UC, and help prevent relapses.
  • Corticosteroids: These medications suppress the whole immune response and treat moderate to severe UC. Corticosteroids can cause short- and long-term side effects, and are generally only used to treat acute inflammation before switching to another medication.
  • Immunomodulators: These medications suppress the immune system response to prevent further inflammation. Immunomodulators can take several months to start working. People may use them if aminosalicylates and corticosteroids are not effective in causing remission of UC.
  • Janus Kinase (JAK) inhibitors: JAK inhibitors suppress the immune system. They block an enzyme called the JAK enzyme, which causes inflammation. People may take JAK inhibitors to treat moderate to severe UC.
  • Biologics: These medications are protein-based and come from materials that occur naturally. Biologics are antibodies that prevent certain proteins within the body from causing inflammation. Biologics can help to treat moderate to severe UC.

Learn more about medical treatments for ulcerative colitis here.


A person should discuss any dietary changes they are considering making with their doctor. Medical treatment may be more effective in preventing symptoms than dietary changes.

The Crohn’s and Colitis Foundation suggest the following diets may be helpful in managing IBD symptoms:

  • carbohydrate exclusion diet
  • Mediterranean diet
  • low-fiber diet
  • low fermentable, oligo-, di-, monosaccharides and polyols (FODMAP) diet
  • gluten-free diet

Learn which foods to eat and avoid with ulcerative colitis here.

Ulcerative colitis is an autoimmune condition in which the immune system attacks healthy tissue in the gut. This causes inflammation of the large intestine, which causes the symptoms of UC.

Without proper treatment, UC could lower the immune system. Certain medications to treat UC may also suppress the immune system.

People can discuss with their doctor the benefits and risks of certain treatments for UC, as well as any dietary changes which may help manage UC symptoms.