Months After Infection, Some Patients Continue Shedding COVID-19 in Their Feces

gut illo

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Key Takeaways

  • A new study found that people continue to shed COVID-19 in their feces for months after their infection.
  • While it’s unlikely for people to be infected through feces, the study offers insights on how the virus may manifest in the gut and potentially other areas of the body.
  • Wastewater surveillance is used as a method for tracking COVID-19 cases and trends. It can sometimes pick up data from infectious people who did not seek out lab-based testing.

A new study on the impact of COVID-19 on gut health may present a roadmap for better understanding long COVID.

The study, which tested stool samples of people who were previously infected with COVID-19, found that some people continue to shed the virus in their feces for as long as seven months after their diagnosis.

The study adds to research on COVID-19’s persistence in the gut microbiome and it could motivate future studies on where COVID-19 may linger in the body and how it may produce ongoing infection or immune reaction.

“These findings may form the basis of why people are developing long COVID,” Ami Bhatt, MD, PhD, an associate professor of medicine and genetics at Stanford University and an author of the study, told Verywell.

Bhatt said that COVID-19 genetic material—and potentially the virus itself—could be “hiding out in parts of the body for a much longer period” than expected.

So far, data suggests that the virus is mostly spread through respiratory droplets, and people are unlikely to get COVID-19 through fecal-oral transmission if they wash their hands properly. “Usually, infections that are spread by fecal-oral routes manifest as food borne illnesses, or are acquired through exposure to surfaces, water or foods that have been exposed to feces and have not been cleaned properly,” Bhatt said.

Does This Affect Wastewater Surveillance?

Health authorities have been tracking COVID-19 trends with wastewater surveillance. When it comes to predicting future surges, this surveillance method may have an advantage over lab-based sequencing, which may not have comprehensive data due to a significant reduction of PCR testing sites.

Based on the new study, wastewater surveillance could hold more clues about COVID-19, such as tracking prior infections. It could better quantify the peak of surges, particularly during times when people are less likely to seek testing.

“It helps us know when [COVID-19] is on the rise, and it will also help us understand when it’s on its way out,” Bhatt said.

Some researchers at Stanford are working to devise tools for how to ensure that both old and new cases are being properly recorded, Bhatt said.

Even without separating old cases where people are no longer infectious, wastewater surveillance remains a fairly accurate tool for tracking new cases, according to Kenny Beckman, PhD, director of the University of Minnesota’s Biomedical Genomics Center, who monitors wastewater surveillance in the Twin Cities.

Only 12.7% of the study participants continued to shed virus four months after diagnosis, and only 3.8% seven months after diagnosis. Beckman said people who have acute COVID-19 infections will still be contributing the “vast majority of the signal to wastewater.”

Quantifying COVID-19's Impact on Gut Health

While previous research has shown that COVID-19 can cause gastrointestinal symptoms such as diarrhea and vomiting, it was not clear whether the virus could infect the gut directly. Bhatt’s study suggests that the latter may be true.

“Our work—taken in the context of other work—suggests that there is a real infection of the gut with this virus. And that might be what is responsible for the GI symptoms that some people are having,” Bhatt said.

These findings may differ among variants, as Omicron appears to produce more GI symptoms than previous strains, she added.

“On one hand, this might sound very strange and unlikely. On the other hand, we know that there are coronaviruses that infect other mammals... that are actually diarrheal pathogens,” Bhatt said.

What This Means For You

Wastewater surveillance is used as a method for tracking COVID-19 cases and trends. It can sometimes pick up data from infectious people who did not seek out lab-based testing.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Natarajan A, Zlitni S, Brooks EF, et al. Gastrointestinal symptoms and fecal shedding of SARS-CoV-2 RNA suggest prolonged gastrointestinal infection. Med (N Y). Published online April 13, 2022. doi:10.1016/j.medj.2022.04.001

  2. Wölfel R, Corman VM, Guggemos W, et al. Virological assessment of hospitalized patients with COVID-2019Nature. 2020;581(7809):465-469. doi:s41586-020-2196-x

  3. Centers for Disease Control and Prevention. National Wastewater Surveillance System (NWSS).

  4. Kariyawasam JC, Jayarajah U, Riza R, Abeysuriya V, Seneviratne SL. Gastrointestinal manifestations in COVID-19Trans R Soc Trop Med Hyg. 2021;115(12):1362-1388. doi:10.1093/trstmh/trab042

By Claire Wolters
Claire Wolters is a staff reporter covering health news for Verywell. She is most passionate about stories that cover real issues and spark change.