Covid can spread from dead bodies, scientists report

Like a zombie in a horror movie, the coronavirus can survive long after death in infected patients and even spread to others, according to two startling studies.

The risk of contagion is mainly to those who handle cadavers, such as pathologists, coroners and medical staff, and in settings such as hospitals and nursing homes, where many deaths can occur.

While cadaver transmission is unlikely to be a major factor in the pandemic, bereaved family members should exercise caution, experts said.

“In some countries, people who have died from Covid-19 are left unattended or returned to their homes,” said Hisako Saitoh, a researcher at Chiba University in Japan who has published two recent studies on the phenomenon.

“So I think it’s knowledge that the general public should be aware of,” he wrote in an email.

Several studies have found traces of infectious virus in cadavers up to 17 days after death. Dr. Saitoh and his colleagues went further and showed that dead bodies can carry significant amounts of infectious virus and that dead hamsters can transmit it to live cage mates.

The research has not yet been reviewed for publication in a scientific journal, but outside experts said the studies were well done and the results compelling.

The risk of a living patient spreading the coronavirus is far greater than the potential transmission from cadavers, said Dr. pointed out Saitoh and other scientists.

If cadaveric infection accounted for a large number of cases, “we would have noticed, wouldn’t we?” said Vincent Munster, a virologist at the National Institute of Allergy and Infectious Diseases.

Still, “When there’s an infectious virus, there’s always a risk of transmission,” he continued. “I don’t think it’s something that’s often brought up.”

In the United States, bodies are usually embalmed or cremated shortly after death. But in the Netherlands, where Dr. Munster grew up, as in many parts of the world, family members are allowed to wash and dress the corpses.

In July 2020, the Japanese government asked bereaved family members to keep their distance from dead bodies and not to touch them – let alone look at them. Officials also recommend sealing bodies in impermeable bags and cremating them within 24 hours.

The guidelines were revised in May 2022 to allow family members to see loved ones who have died from Covid but “in a hospital room with adequate infection control”.

These guidelines prompted Dr. Saitoh to find out what happens to the virus in the body after death.

He and his colleagues examined samples from the nose and lungs of 11 people who had died from Covid. The researchers found that high levels of the virus persisted in six of the 11 bodies 13 days after death.

“It was surprising that infection titers remained at the same high level as in clinical patients,” said Dr. Saito wrote. “Most surprising, however, were the results of the animal experiments.”

In these experiments, he and his colleagues found that hamsters that died within days of being infected with the coronavirus could transmit it to other animals. Humans are also most likely to be infected if a patient dies shortly after infection, when the virus concentration in the body is very high, the researchers said.

The team found more virus in the lungs of human cadavers than in the upper airways. That suggests those performing autopsies should take extra care when handling the lungs, experts said. DR Saitoh referred to a study from Thailand that described a forensic practitioner who appeared to have contracted the infection while on the job.

Gases that build up after death can be expelled through any opening in the body, including the mouth, and transmit infectious viruses, the researchers said. Embalming or practicing what is known as “angelic care” — a Japanese ritual of plugging the mouth, nose, ears, and anus with cotton pads — prevented transmission, they found.

Contagious corpses are not without precedent. Most famously, burial and burial practices have fueled major outbreaks of the Ebola virus in Africa.

But the coronavirus is very different, noted Angela Rasmussen, a researcher at the Vaccines and Infectious Diseases Organization at the University of Saskatchewan in Canada.

Up to 70 percent of those infected with Ebola die, compared to about 3 percent of those diagnosed with Covid-19. And the Ebola virus invades every part of the body, so the risk of transmission, even after death, is far greater than that theoretically posed by the coronavirus.

“With Ebola, it’s definitely direct contact with bodily fluids, because if someone dies from Ebola, you have high Ebola titers pretty much everywhere,” said Dr. said Rasmussen.

She was initially skeptical that the coronavirus could spread from corpses, but found the new studies compelling.

“Most people probably still have a lot more to worry about catching Covid from their living neighbors than their recently deceased ones,” she said.

But they “should be very careful about physical contact with the remains of their loved ones,” she added.

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