A study shows that the coronavirus that causes Covid-19 can spread within days from the respiratory tract to the heart, brain and almost any organ system in the body, where it can survive for months.
In what they describe as the most comprehensive analysis to date of the distribution and persistence of the SARS-CoV-2 virus in the body and brain, say scientists at the US National Institutes of Health. They discovered that pathogens have the ability to replicate in human cells a lot. Respiratory.
The results, published online Saturday in a manuscript under review for publication in the journal Nature, indicate that delayed viral clearance is a potential cause of symptoms persistent flare-ups of so-called people with persistent Covid. Understanding how the virus survives, along with the body’s response to any virus reservoir, holds promise for improving care for those who are sick, the authors say.
Ziyad Al-Aly, director of the clinical epidemiology center at the St. Louis in Missouri, who has led separate studies on the long-term effects of Covid-19 said: “This is particularly important work. “We have long been scratching our heads and questioning why prolonged Covid seems to affect so many organ systems. This article sheds light on and may help explain why prolonged Covid can have such effects. can occur even in people with mild or no symptoms. epidemics.”
The findings and techniques have yet to be reviewed by independent scientists and are primarily related to data collected from Covid cases that have died, not patients with persistent Covid or “acute post-acute sequelae.” of SARS-CoV-2″ as it is also called.
Surprising find
The propensity of coronavirus to infect cells outside the airways and lungs is controversial, with numerous studies providing evidence for and against this possibility.
The study, conducted at the NIH in Bethesda, Maryland, was based on extensive sampling and analysis of tissues taken during autopsies on 44 patients who died after contracting the coronavirus during the first year of the pandemic. in U.S.A
Daniel Chertow, who runs the NIH’s emerging pathogens division, and his colleagues, wrote:
The team detected persistent SARS-CoV-2 RNA in many parts of the body, including regions across the entire brain, for a period of 230 days after the onset of symptoms. They say this may represent infection with faulty viral particles, which have been described in cases of persistent measles virus infection.
“We don’t fully understand Covid, but these changes may explain the ongoing symptoms,” said Raina MacIntyre, professor of global biosecurity at the University of New South Wales in Sydney. . MacIntyre was not involved in the study, which she said “provides a warning about mass infection in children and adults.”
Methods of Prevention
“We still don’t know what the burden of chronic disease will lead to in the years to come,” she said. “Are we seeing young-onset heart failure survivors, or early-onset dementia? These are unanswered questions that require a precautionary public health approach.” to minimize the spread of this virus.”
In contrast to other Covid autopsy studies, the NIH team’s post-mortem tissue collection is more comprehensive and typically takes place within about a day of a patient’s death.
The researchers also used a variety of tissue preservation techniques to detect and quantify virus levels, as well as grow viruses collected from a variety of tissues, including the lungs, heart, small intestine, and adrenal glands. kidney from a Covid patient who died within the first week of illness.
“Our results suggest that although the highest burden of SARS-CoV-2 is in the respiratory tract and lungs, the virus may be shedding early in infection and transmission,” the authors said. infect cells throughout the entire body, including the brain,” the authors said.
MacIntyre at the University of New South Wales said the study provides pathological data that supports the findings of previous research showing that SARS-CoV-2 directly kills heart muscle cells and survivors. After infection, there will be cognitive decline.
Phase ‘Viremic’
The NIH researchers suggest that infection of the pulmonary system can lead to an early “viremic” stage, in which the virus is present in the blood and is seeded throughout the body, including across the blood-brain barrier, even through in patients with mild or no symptoms. One patient in the autopsy study was a minor who likely died from unrelated convulsive complications, suggesting that children with mild Covid-19 infections can also develop systemic infections. , they say.
The less efficient clearance of the virus in tissues outside the lung system may be related to a weak immune response outside the respiratory tract, the authors say.
SARS-CoV-2 RNA was detected in the brains of all six autopsy patients who died more than one month after developing symptoms and on most of the assessed sites in the brain during the year, including included one patient who died 230 days after the onset of symptoms.
Al-Aly at the St. Veterans Affairs Health Care System. Focusing on multiple brain regions is particularly helpful, says Louis.
“It could help us understand the neurocognitive decline or ‘brain fog’ and other neuropsychiatric manifestations of long Covid,” he said. “We need to start thinking of SARS-CoV-2 as a systemic virus that can resolve in some people, but in others can persist for weeks or months and produce a prolonged Covid – a multifaceted systemic disorder.”
(This story has not been edited by NDTV staff and was automatically generated from the feed provided.)
