In the largest study to track SARS-CoV-2 RNA in feces and symptoms of COVID-19, scientists at Stanford University in California found that nearly half of infected patients leave traces of the virus in their waste in the week following infection 4% of patients still excrete them. after seven months. Researchers also linked coronavirus RNA in feces to gastric upset, and concluded that SARS-CoV-2 directly infects the gastrointestinal tract, where it can hide.
“This raises the question of whether ongoing infections in hidden parts of the body may be important for a longer COVID,” said Ami Bhatt, a senior author of the study published online Tuesday in the journal Med and a professor of medicine and genetics at Stanford. Associate Professor She said in an interview, the Linging virus can directly invade cells and damage tissues or produce proteins that are stimulating the immune system.
No one yet knows what causes the constellation of post-Covid symptoms, often called prolonged covids, that afflict 5% to 80% of people following SARS-CoV-2 infection. It is possible that at least four different biological mechanisms give rise to different conditions or subtypes of chronic COVID, said Akiko Iwasaki, a professor of immunobiology and molecular, cellular and developmental biology at Yale University.
“Long COVID is the potential for many different diseases,” Iwasaki said in an interview last week at his lab in New Haven, Connecticut. In one of these forms, persistent SARS-CoV-2 can trigger a harmful immune response that can lead to diseases that can be suppressed with drugs that target the virus, he said.
“I’ve heard of people recovering from antivirals or monoclonals for a long time,” said Iwasaki, who wants to collaborate on clinical studies of potential treatments. “I’m really excited at the prospect of testing for long-term direct antiviral and monoclonal antibodies” to COVID, she said.
pfizer drug
Pfizer Inc.’s PaxLovid received emergency use authorization from the Food and Drug Administration in December, launching the first COVID treatment taken in pill form. Pfizer does not have any long-term COVID studies going on, but is assessing their potential, the drugmaker said in an email.
Karl Diefenbach, director of the AIDS department at the National Institute of Allergy and Infectious Diseases, said once antiviral products are fully approved, instead of being authorized as most, researchers will have more freedom to study them in combination. . Diefenbach is also co-leading an antiviral program to counter the threat of the pandemic.
Some scientists believe that Omicron and its subtypes developed in the same patient with a long-term covid infection. Medicines that accelerate the eradication of such infections may reduce the risk that new immune-suppressing strains will emerge.
SARS-CoV-2 is mostly spread through respiratory particles released from the airways of infected individuals. However, it is difficult to show that fecal matter contains infectious particles, as this requires isolating, purifying and testing live virus from microbe-containing feces in laboratories specifically equipped to handle dangerous pathogens.
The digestive tract is the main site outside the respiratory tract for SARS-CoV-2 persistence and periodic viral shedding, researchers in China showed in 2020. Traces of the virus were identified within weeks of the emergence of COVID and prompted the use of wastewater. Surveillance to measure the spread of the pandemic.
autopsy findings
“The gut is a place where people have consistently reported antigens and RNA,” Iwasaki said. Others have reported evidence of persistence in lymph tissues, the brain, and other organs, mostly from autopsies performed on people who died of severe, intense bouts. covid. “It is not clear how much is actually happening in tall Covid patients,” she said.
Stanford’s Bhatt said there is a lack of data on the frequency and duration of coronavirus in the stool of people with mild to moderate covid. In May 2020, as part of a separate study, he and his colleagues began monitoring long-term COVID symptoms and the degree and location of viral shedding in people.
When researchers analyzed stool samples from 113 participants at specific time points after infection, about 13% were still shedding viral RNA four months later, when they had cleared the virus from their airways. Traces of the virus were found in the stools of two participants approximately 210 days after infection.
The researchers were not able to isolate enough viral RNA to determine which variant infected the participants, or to conclusively show that the strain was isolated from a given individual at early and later time points. The samples were the same strain. Nevertheless, samples were collected in the first year of the epidemic, when the likelihood of reinfection with another strain or variant was low during the study period.
Bhatt, who trained as a cancer clinician and studied the interaction of gut microbes and patient outcomes, says the new findings will improve understanding of clues that can be obtained from sewage on community transmission of the coronavirus. Huh.
“When we look at wastewater-based epidemiology and try to interpret it, it is important that we understand how much people are shedding and for how long,” she said.
This story has been published without modification in text from a wire agency feed. Only the title has been changed.