Kinder COVID? Israeli lab probes whether virus mutating to become less vicious

As Italian doctor says virus has changed from an ‘aggressive tiger’ to a ‘wild cat,’ Tel Aviv virologist is tasked by Health Ministry to test ‘attenuation’ theory

Nathan Jeffay is The Times of Israel's health and science correspondent

Illustrative image: Joyful man, cured of the disease, standing at a railway station in a medical mask (iStock/Nikolay Chekalin)
Illustrative image: Joyful man, cured of the disease, standing at a railway station in a medical mask (iStock/Nikolay Chekalin)

Israeli researchers have started carrying out genome analysis to test whether the novel coronavirus is changing to become less vicious.

Evolutionary virologist Adi Stern told The Times of Israel that she has been tasked by the Health Ministry with conducting an analysis of dozens of samples from recent coronavirus patients, and comparing them to old samples.

“The hypothesis is that the virus has attenuated, which means it’s become less virulent, and there may be a genetic signal that shows this,” she said, adding that she was sequencing the genome of the virus in recent infections and contrasting it with samples from March.

Stern, who runs a Tel Aviv University virus lab, said that if this proves correct, it could explain why a smaller proportion of COVID-19 patients today end up being hospitalized in serious condition. It would have a major impact on the way governments and doctors plan for the rest of the pandemic, she commented, adding that the analysis will take several more weeks.

Adi Stern of Tel Aviv University’s School of Molecular Cell Biology and Biotechnology (courtesy of Tel Aviv University)

As Israel is getting underway with the research, an Italian doctor has been making headlines with claims that the virus is becoming gentler.

“It was like an aggressive tiger in March and April but now it’s like a wild cat,” Prof. Matteo Bassetti told The Sunday Telegraph.

Bassetti, the chief of infectious diseases at San Martino General Hospital in Genoa, said: “Even elderly patients, aged 80 or 90, are now sitting up in bed and they are breathing without help. The same patients would have died in two or three days, before.”

In Israeli hospitals, there are some similar suggestions.

“The disease is losing its virulence by mutation,” the leading infectious diseases specialist David Greenberg told The Times of Israel.

A top World Health Organization doctor, however, has spoken out against such claims.

“We need to be careful: this is still a killer virus,” WHO emergencies director Michael Ryan told a virtual press conference on June 1, following earlier claims that the virus was weakening. “We need to be exceptionally careful not to create a sense that, all of a sudden, the virus, by its own volition, has now decided to be less pathogenic. That is not the case at all.”

Doctors at Tel Aviv Sourasky Medical Center treat a patient in the coronavirus unit, May 4, 2020. (Yossi Aloni/Flash90)

But Greenberg, head of pediatrics and the pediatric infectious diseases unit at Soroka University Medical Center in Beersheba, disagrees, and thinks there is a sound logic why a virus may undergo a softening.

”It seems to adapt to the human being, and doesn’t want to kill the hosts but live on in them and flourish. We can see it all over the world, not just in Israel,” he said.

David Greenberg, head of pediatrics and the pediatric infectious diseases unit at Soroka University Medical Center (courtesy)

Greenberg believes this helps explain why the proportion of elderly people among the newly infected in Israel is low compared to earlier in the pandemic — while he would expect it to be higher as, post-lockdown, the elderly now have more contact with kids. He thinks that a softening of the virus means that the elderly are more prone to have the virus but remain unaware.

“A lot of old people are mixing with children, but the virus mutates; [there could be] lots of parents and grandparents who don’t know they have it,” he said.

Stern, who is testing the theory, is more circumspect. She suggested that the hypothesis that the virus is weakening is something of a long shot, saying that a range of other factors, including increased medical knowledge, may be improving outcomes.

Nevertheless, she is “hopeful,” and commented: “If this is true then it’s important to realize it, because it would affect policymaking.

“A lot of the models that are trying to predict the virus spread, such as how many people with the disease will need hospitalization and ventilation, are based on what we’ve seen so far. If the virus is becoming less virulent, this is important to understand.”

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