Incidence of persistent SARS-CoV-2 gut infection in patients with a history of COVID-19: Insights from endoscopic examination

The study titled “Incidence of persistent SARS-CoV-2 gut infection in patients with a history of COVID-19: Insights from endoscopic examination” offers significant insights into the long-term effects of COVID-19 on the gastrointestinal system.

Here’s a detailed summary:

Background and Aims: The study investigates the common occurrence of gut infection during acute COVID-19 and the possibility of persistent SARS-CoV-2 gut infection months after the initial infection, potentially related to long-COVID syndrome. The primary objective was to determine the incidence of this persistent gut infection in patients with a history of COVID-19 undergoing endoscopic examination​​.

Methodology: Conducted from October 2022 to February 2023, this cross-sectional study involved patients undergoing upper or lower gastrointestinal endoscopy (UGE or LGE). Those with previous PCR-confirmed COVID-19 were included. The primary endpoint was the detection of persistent SARS-CoV-2 gut infection using immunohistochemistry in endoscopic biopsies. The study also aimed to assess the relationship between positive immunostaining and various clinical factors, including prior COVID-19 infection history, symptoms, and vaccination status​​.

Participants: The study included 249 patients, predominantly males (52%), with a median age of 53 years. Hypertension and diabetes mellitus were the most common comorbidities. A majority of the biopsies were from the upper gastrointestinal tract (67%)​​.


  • Immunostaining Findings: Positive immunostaining for SARS-CoV-2 was more common in UGE biopsies (37.34%) than in LGE biopsies (16.87%). The presence of SARS-CoV-2 nucleocapsid proteins was identified in 76 biopsies (31% of total), primarily in the stomach.
  • Risk Factors: Smokers and patients with diabetes showed a significantly higher incidence of positive immunostaining. Smokers had an odds ratio (OR) of 7.68 for a positive test, indicating a much higher likelihood of persistent gut infection. Diabetic patients also had a higher OR (2.84) for a positive test result.
  • Vaccination Status: Vaccination status did not significantly influence the likelihood of a positive stain test result​​.


  • Gastrointestinal Involvement in Acute COVID-19: The study discusses the severe gut involvement during acute COVID-19, including symptoms like gastrointestinal bleeding and various endoscopic findings like ulcers and erosions. These manifestations are attributed to the direct invasion of gastrointestinal cells by SARS-CoV-2.
  • Pathophysiology: SARS-CoV-2 uses the ACE2 receptor, abundant in the small intestine’s enterocytes, for cell entry. The virus can directly damage the gastrointestinal epithelium, leading to symptoms like diarrhea. Prolonged gastrointestinal infection or viral shedding is also indicated by the presence of viral particles in feces, even when respiratory tests are negative.
  • Persistent Gut Infection: The study highlights the presence of viral RNA and nucleocapsid proteins in various gastrointestinal organs months post-infection, suggesting that the gut can act as a long-term reservoir for SARS-CoV-2. This persistence might be linked to extended gastrointestinal symptoms observed in some long-COVID cases​​.

Conclusions: The study concludes that gut mucosal tissues can harbor SARS-CoV-2 for months following the primary infection. Smokers and individuals with diabetes are at an increased risk of persistent viral gut infection. These findings provide crucial insights into the dynamics of SARS-CoV-2 infection in the gastrointestinal system and underscore the need for further research in understanding long COVID.

This detailed analysis offers a comprehensive overview of the study, making it suitable for your blog post and providing valuable information on the long-term gastrointestinal impacts of COVID-19.

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