In For The Long Haul With COVID

"This is remarkably important work. For a long time now, we have been scratching our heads and asking why long COVID seems to affect so many organ systems."

"This paper sheds some light, and may help explain why long COVID can occur even in people who had mild or asymptomatic acute disease."

Zyad Al-Aly, director, clinical epidemiology centre, Veterans Affairs St.Louis Health Care System, Missouri

 

"We don't fully understand long COVID, but these changes could explain ongoing symptoms."

"[The research] provides a warning about being blase about mass infection in children and adults."

"We don't yet know what burden of chronic illness will remain in years to come. Will we see young-onset cardiac failure in survivors, or early onset dementia?"

"These are unanswered questions which call for a precautionary public health approach to mitigation of the spread of the virus."

Raina MacIntyre, professor of global biosecurity, University of New South Wales, Sydney

"Our results collectively show that while the highest burden of SARS-CoV-2 is in the airways and lung, the virus can disseminate early during infection and infect cells throughout the entire body, including widely throughout the brain."

NIH Study authors

 

A new study concludes that the coronavirus causing COVID-19 has the ability to spread within days from the airways to the heart, brain and just about every bodily organ system, in addition to which it may persist for months. The study authors describe their work as the most comprehensive analysis to the present of the SARS-CoV-2 virus's widespread distribution and duration in both body and brain. 

 

Scientists at the U.S. National Institutes of Health discovered that the pathogen has the capacity to replicate in human cells beyond the respiratory tract.

The manuscript, pre-released on line, is currently under review preparatory to publication in the journal Nature; its results spell out delayed viral clearance as a possible contributor to the pernicious symptoms stubbornly wracking the minds and bodies of long-COVID sufferers. Knowing how the virus is able to persist, as well as the body's response to a viral reservoir has the potential to aid in improving care for those sufferers.

The investigative discoveries and the techniques used are yet to be reviewed by independent scientists, and relate to data gathered from fatal COVID cases, and not from people suffering with long COVID or "post-acute sequelae of SARS-CoV-2", the authors point out. Numerous earlier studies provide evidence both for and against the possibility that the coronavirus has the propensity to infect cells outside the airways and lungs.

 

Undertaken at the National Institutes of Health in Bethesda, Maryland, the research is based on sampling extensively, and analysis of tissues reserved during autopsies on 44 American patients who failed to survive their encounter with the coronavirus. Daniel Chertow, who heads the NIH emerging pathogen section, wrote that the burden of infection outside the respiratory tract and the time it takes to clear the virus from infected tissues, particularly in the brain, fail to be characterized.

Persistent SARS-CoV-2 RNA was detected by the study group in multiple parts of the body, as well as throughout the brain, for up to 230 days after symptom onset, which may represent infection with defective virus particles, seen as well in persistent infection with the measles virus. The NIH team's post-mortem tissue collection was comprehensive, occurring within about a day of the patients' demise.

A variety of tissue preservation techniques to detect and quantify viral levels was also used, along with growing the virus collected from multiple tissues, including lung, heart, small intestine and adrenal gland. Pathological data can be drawn from the study supporting findings of previous research indicating, as an example, that SARS-CoV-2 directly destroys heart muscle cells, and those who survive an infection suffer cognitive deficits.

Infection of the pulmonary system may result in an early "viremic" phase where the virus is seeded throughout the body, including in patients experiencing mild or no symptoms, posit the NIH researchers. An example given was that of a juvenile included in the autopsy study who was presumed to have died from unrelated seizure complications, suggesting infected children with mild COVID-19 onset are also able to experience systemic infection.

Getty -- The Atlantic