Summary: Autopsy tissue samples from 44 people who died of COVID-19 showed that SAR-CoV-2, the virus that causes the coronavirus, had spread throughout the body and to the brain, with traces of the virus lingering for 8 months.
Source: University of Minnesota
Analysis of tissue samples from autopsies of 44 people who died with COVID-19 shows the SAR-CoV-2 virus spread throughout the body – including the brain – and persisted for nearly eight months.
The study was published in Nature.
Scientists from the National Institutes of Health (NIH) tested samples from autopsies performed from April 2020 to March 2021. They performed extensive sampling of the nervous system, including the brain, in 11 of the patients.
RNA and viable virus in various organs
All patients died with COVID-19 and none were vaccinated. Blood plasma from 38 patients tested positive for SARS-CoV-2, three tested negative, and plasma was not available for the remaining 3.
Thirty percent of patients were female and the median age was 62.5 years. Twenty-seven patients (61.4%) had three or more comorbidities. The median interval between symptom onset and death was 18.5 days.
The analysis showed that SARS-CoV-2, as expected, primarily infected and damaged the airways and lung tissue. But the researchers also found viral RNA in 84 separate body locations and bodily fluids, and in one case they isolated viral RNA 230 days after a patient’s symptoms began.
The researchers detected SARS-CoV-2 RNA and proteins in the hypothalamus and cerebellum of one patient and in the spinal cord and basal ganglia of two other patients. But they found little damage to brain tissue, “despite a significant viral load”.
The researchers also isolated the viable SARS-CoV-2 virus from various tissues inside and outside the respiratory tract, including the brain, heart, lymph nodes, gastrointestinal tract, adrenal gland and the eyes. They isolated the virus from 25 of the 55 samples tested (45%).
The authors wrote: “We demonstrated virus replication in multiple non-respiratory sites during the first two weeks after symptom onset.”
They add, “Our focus on short post-mortem intervals, a comprehensive standardized approach to tissue collection, brain dissection prior to fixation, tissue preservation in RNA later, and flash freezing of fresh tissue allowed detection and quantification of SARS-CoV-2 RNA levels with high sensitivity by [polymerase chain reaction] and [in situ hybridization]as well as isolating the virus in cell culture from several non-respiratory tissues, including the brain, which are notable differences from other studies.
Possible ramifications for the long COVID
The study’s lead author, Daniel Chertow, MD, MPH, said in an NIH press release that prior to the work, “the thinking in the field was that SARS-CoV-2 was primarily a respiratory virus. “.
The discovery of viral presence throughout the body – and sharing these findings with colleagues a year ago – has helped scientists explore a relationship between widely infected body tissues and “long COVID”, or the symptoms that persist for weeks and months after infection.
Part of a Paxlovid RECOVER trial set to begin in 2023 includes an extension of the autopsy work highlighted in the Nature study, according to co-author Stephen Hewitt, MD, Ph.D., who serves on the steering committee of the RECOVER project. Autopsies from the RECOVER trial include people both vaccinated and infected with worrying variants – data that was not available in yesterday’s study.
“We hope to replicate viral persistence data and investigate the relationship to long COVID,” Hewitt said. “In less than a year, we have about 85 cases and we are working to expand those efforts.”
See also
About this COVID-19 and neurology research news
Author: Jim Wappes
Source: University of Minnesota
Contact: Jim Wappes – University of Minnesota
Image: The image is attributed to the researchers
Original research: Access closed.
“SARS-CoV-2 infection and persistence in human body and brain at autopsy” by Sydney R. Stein et al. Nature
Abstract
SARS-CoV-2 infection and persistence in human body and brain at autopsy
Coronavirus disease 2019 (COVID-19) is known to cause multiple organ dysfunction during acute infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with some patients experiencing prolonged symptoms, called post-acute sequelae of SARS-CoV-2.
However, the burden of infection outside the respiratory tract and the viral clearance time are not well characterized, particularly in the brain.
Here, we performed full autopsies on 44 patients who died with COVID-19, with extensive central nervous system sampling in 11 of these patients, to map and quantify the distribution, replication, and cell-type specificity of SARS-CoV. -2 throughout the human body, including the brain, from acute infection to more than seven months after the onset of symptoms.
We show that SARS-CoV-2 is widely distributed, primarily among patients who died of severe COVID-19, and that virus replication is present in multiple respiratory and non-respiratory tissues, including the brain, early in life. infection. Additionally, we detected persistent SARS-CoV-2 RNA in multiple anatomical sites, including throughout the brain, up to 230 days after symptom onset in one case.
Despite widespread distribution of SARS-CoV-2 RNA throughout the body, we observed little evidence of inflammation or direct viral cytopathology outside of the respiratory tract. Our data indicate that in some patients, SARS-CoV-2 can cause systemic infection and persist in the body for months.
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