Severe COVID-19 linked to higher risk of gastrointestinal conditions for two years

2 November 2026

People who have been hospitalised with COVID-19 are at increased risk of developing a range of digestive health problems. This effect can last for up to two years after infection, according to a new study involving researchers at the University of Bristol.

Published in BMJ Public Health, the study analysed health records from more than 18 million adults in England. The study team wanted to investigate whether COVID-19 was linked to later gastrointestinal disease, and whether vaccination made a difference.

Researchers used data from the OpenSAFELY platform, which provides secure access to linked NHS health records. They examined rates of 10 digestive conditions, including:

Gastrointestinal bleeding
Acid reflux
Irritable bowel syndrome (IBS)
Stomach ulcers
Gallstones
Pancreatitis (inflammation of the pancreas)

The team found that people diagnosed with COVID-19 were more likely to develop gastrointestinal diseases than those who had not had the infection. Risks were highest in the weeks immediately after diagnosis. However, they remained elevated for up to two years among people whose COVID-19 infection was severe enough to require hospital admission.

The strongest associations were seen for gastrointestinal bleeding. In the first month after hospitalisation with COVID-19, the risk of upper gastrointestinal bleeding was around 20 times higher than before or without infection. Although the risk decreased over time, it was still elevated more than a year later. Similar patterns were observed across other digestive conditions.

Importantly, the study found that these long-term digestive health risks were less pronounced among people who had been vaccinated before their COVID-19 infection. Vaccinated people generally experienced lower rates of post-COVID gastrointestinal disease than unvaccinated people, particularly when infections did not result in hospitalisation.

The findings suggest that vaccination may help reduce not only the risk of severe COVID-19, but also some of its longer-term health consequences.

Dr Rachel Denholm, Associate Professor in Applied Health Data Sciences at the University of Bristol and senior study author, said:

“Our findings show that the impact of COVID-19 can extend well beyond the initial infection.

“People who experienced severe COVID-19 were more likely to develop a range of digestive health conditions, and these increased risks could persist for years after infection.

“Our results also showed that the longer-term digestive health risks were lower among vaccinated people, reflecting the impact role vaccination plays in reducing severe COVID-19.”

Researchers say their findings highlight the importance of monitoring patients who have had severe COVID-19 for signs of gastrointestinal disease, even after they have recovered from the initial infection. They also reinforce the value of vaccination in reducing the long-term burden of COVID-19 on patients and healthcare services.