Coronavirus can persist in tissues for up to 230 days

(ORDO NEWS) — A new study by American scientists showed that certain tissues of the body were posthumously affected by SARS-CoV-2 in absolutely all patients who died from Covid-19, although the virus was found in vivo in blood plasma samples only in a third of cases.

In a preprint currently undergoing peer-review for publication in the journal Nature, researchers at the US National Institutes of Health analyzed tissue samples taken during autopsies of 44 patients who died of coronavirus infection in 2020. In some of them, SARS-CoV-2 remained viable for up to 230 days.

As the authors emphasized, they used a “more comprehensive approach” postmortem tissue harvesting, which was carried out on the first day after death (maximum – after 26.2 hours). Scientists have also used various methods of preserving tissues, primarily flash freezing – in order to accurately determine the real viral load in them. We used both highly sensitive modifications of the PCR technique and the culture method, that is, the cultivation of SARS-CoV-2 in specially designed cells.

All 44 people who underwent autopsy (autopsy) were in hospitals, death occurred on average 35.2 days after hospitalization, maximum – after 230 days. Seroconversion (the formation of antibodies to SARS-CoV-2) was detected in 38 cases. 29.5% of cohort participants are women, median age is 59.2 years.

All patients were severe, with various comorbidities, at least one underlying disease was present in 95.5% of cases. The most common were arterial hypertension (54.5%), obesity (52.3%) and chronic diseases of the respiratory system (34.1%). At the same time, 81.8% managed to be on mechanical ventilation, 22.7% – on ECMO, 40.9% – on dialysis.

Coronavirus RNA was isolated in 97.7% of samples taken from the respiratory tract, in 86.4% from the lymph nodes, and in 79.5% from the tissues of the heart and blood vessels. In addition, the genetic material of the pathogen was isolated from the kidneys, endocrine glands, reproductive organs, muscles, skin, adipose tissue, peripheral nerves, formations and eye fluids. In 90.9% of samples,

it was found in the brain. At the same time, in living plasma samples of patients’ blood, the virus was detected only in 12 cases, and posthumously certain tissues were affected in absolutely all participants.

“Collectively, our results indicate that although the upper respiratory tract and lungs are the most burdened with SARS-CoV-2, the virus can spread early in infection and infect cells throughout the body, including the entire brain.

While previous studies suggested that the spread of the virus occurs through cell traffic due to reports of the inability to culture the virus from blood, our data support an early phase of viremia, during which the pathogen spreads throughout the body, ”the authors conclude.

They emphasize that the coronavirus is able to penetrate the blood-brain barrier, and this can occur in the early stages, when Covid-19 is asymptomatic or with mild manifestations. Long-term persistence of the virus in some tissues is also possible, although the person in this case remains non-infectious (similar processes were previously described for measles). It is possible that this information may shed light on postcoid syndrome, the nature of which is still poorly understood.

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