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Daily briefing: Underwhelming trial results for leading Chinese COVID vaccine

The CoronaVac vaccine, developed by Sinovac in China, reports mixed results in Brazil. Plus, what we know about COVID’s toll on smell and taste, and the mysterious extinction of the dire wolf.

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Underwater photos of Volta’s electric eel (Electrophorus voltai) in Xingu River.

Not always a lone hunter, the Volta’s electric eel can join forces with dozens of its kind to haul in a big catch.L. Sousa

Electric eels hunt in packs

Electric eels (Electrophorus voltai) in Amazon rivers don’t just pack the strongest shock ever measured in a living animal. They also gang up to herd shoals of fish and deliver a coordinated death zap. “I was shocked,” says biologist Douglas Bastos. “This behavior is unprecedented for electrical eels and also rare among freshwater fishes.”

Science | 5 min read

Reference: Ecology and Evolution paper

COVID-19 coronavirus update

COVID’s toll on smell and taste

Many people infected with SARS-CoV-2 lose their sense of smell or taste — even without displaying other symptoms. Some haven’t yet recovered these senses. And for a proportion of people who do, everything smells unpleasant. Although the mechanisms are not fully understood, there is an emerging consensus that smell loss occurs when the coronavirus infects cells that support neurons in the nose. A lack of research means few established treatments exist. But one option is smell training, in which people sniff prescribed odours regularly to relearn them.

Nature | 7 min read

CoronaVac vaccine reports mixed results

Researchers in Brazil have reported that CoronaVac, developed by Sinovac in China, was 50.4% effective at preventing severe and mild COVID-19 in late-stage trials. That’s much lower than those from early trials of the same vaccine in Turkey and Indonesia, and below the efficacy first reported by the Brazil trial team last week. It’s also well below the 90% efficacies of several leading vaccines. But if the latest results check out — they have not been peer reviewed — the two-dose vaccine could be immediately beneficial in countries with raging outbreaks. CoronaVac is stable at refrigerated temperatures and easy to distribute.

Nature | 6 min read

Do dose delays promote dangerous mutations?

Researchers are divided over strategies to extend the time between jabs of two-dose COVID vaccines. Some virologists worry that the approach will create large groups of people with partial immunity. These people might have enough antibodies to slow the virus and avoid developing symptoms — but not enough to wipe it out. This might give SARS-CoV-2 more time to mutate in ways that could compromise vaccine efficacy. Other experts say the risk — which is still just theoretical — doesn’t outweigh the benefits of protecting more people during out-of-control outbreaks. “It’s carnage out there,” says evolutionary microbiologist Andrew Read. “Twice as many people with partial immunity has got to be better than full immunity in half of them.”

Science | 4 min read

Notable quotable

“In virology, as in many other fields, knowing your enemy is critically important.”

Conspiracy theories about the origins of SARS-CoV-2 have led to political interference in essential scientific investigations into the biology of the virus, argues global-health and security researcher Angela Rasmussen. (Nature Medicine | 5 min read)

Features & opinion

Tentacles fold around the head of a human figure

Illustration by Jacey

Futures: The dream cartel

Author Preston Grassmann delves further into the fictional dream market of Canvas Town in the latest short story for Nature’s Futures series. Grassmann was inspired by a festival in Thailand in which crowds gather to release paper lanterns into the sky as a symbol of purging painful memories. “I wanted to take another look at what that might mean if that ‘release’ was more than symbolic,” says Grassmann.

Nature | 4 min read

Podcast: What happened to the dire wolf?

Dire wolves (Canis dirus) were once the most common predator in North America. Then, 13,000 years ago, they disappeared. Ancient genomics and proteomics reveal that dire wolves were very different from similar-looking, smaller grey wolves (Canis lupus), which survive to this day. That genetic difference might have been the stumbling block for dire wolves’ survival, because it couldn’t interbreed with other dog-like animals. The dire wolf broke “rule number one” for surviving as a canid species, says palaeogenomicist Laurent Frantz — hybridizing with others. “The environment was changing quite rapidly at the end of the pleistocene,” Frantz tells the Nature Podcast. “It wasn’t able to adapt fast enough potentially because it wasn’t able to borrow genes from these incoming species.”

Nature Podcast | 32 min listen

Subscribe to the Nature Podcast on Apple Podcasts, Google Podcasts or Spotify.

Reference: Nature paper

Where I work

Clara Barker sitting in a lab surrounded large metallic lab equipment and wearing shoes with blue, pink and white striped soles

Clara Barker is a materials scientist and manager of the Centre for Applied Superconductivity at the University of Oxford, UK.Credit: Leonora Saunders for Nature

Clara Barker is a materials scientist and manager of the Centre for Applied Superconductivity at the University of Oxford, UK. “As you can see from the sole of my shoe, which is decorated with the transgender pride flag, I’m a trans scientist,” says Barker. “I’d long believed that coming out as transgender would be career-ending. Instead, Oxford was the first place where I could be myself, where I’ve enjoyed being in the laboratory, because I was no longer pretending or hiding — I was accepted for being me.” (Nature | 2 min read)

Quote of the day

“I decided to search for ‘number of Black women with degrees in computational biology’ on the Internet and found nothing… The next person that searches for Black women in computational biology will be able to find us.”

Jenea Adams, the founder of the Black Women in Computational Biology Network, discusses the organization and her hopes for efforts to dismantle structural racism in academia. (Nature Computational Science | 9 min read)

Today the lovely Leif Penguinson is watching the snow fall on the River Wharfe in the grounds of Bolton Abbey, North Yorkshire. Can you find the penguin?

The answer will be in Monday’s e-mail, all thanks to Briefing photo editor and penguin wrangler Tom Houghton.This newsletter is always evolving — tell us what you think! Please send your feedback to

Flora Graham, senior editor, Nature BriefingWith contributions by Nicky Phillips

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