COVID vaccines slash risk of spreading Omicron — and so does prior infection

But the benefit of vaccines in reducing Omicron transmission doesn’t last for long.

Ruby Prosser Scully

Nature | August 26, 2022

Vaccinated people are less likely to pass on Omicron than those who have not been immunized.Credit: Frederic J. Brown/AFP/Getty

People who become infected with the Omicron variant are less likely to spread the virus to others if they have been vaccinated or have had a prior SARS-CoV-2 infection, according to a study in US prisons¹. And people who have had a prior infection and been vaccinated are even less likely to pass on the virus, although the benefit of vaccines in reducing infectiousness seems to wane over time.

The findings are good news, says Megan Steain, a virologist at the University of Sydney, Australia. They show that the more exposure people have to the virus, whether through vaccines, boosters or infections, the “higher the wall of immunity”, she says. “If we can keep high levels of booster vaccinations up, then we can decrease how infectious people are when they’re sick,” says Steain.

The study was posted as a preprint on medRxiv this month and has not been peer reviewed.

Mouse embryos grown without eggs or sperm: why and what’s next?

Two research teams grew synthetic embryos using stem cells, long enough to see some organs develop.

Cassandra Willyard

Nature | August 25, 2022

Natural and synthetic mouse embryos grown by developmental biologist Magdalena Zernicka-Goetz’s research group.Credit: Gianluca Amadei, Charlotte Handford

The recipe for mammalian life is simple: take an egg, add sperm and wait. But two new papers demonstrate that there’s another way. Under the right conditions, stem cells can divide and self-organize into an embryo on their own. In studies published in Cell¹ and Nature² this month, two groups report that they have grown synthetic mouse embryos for longer than ever before. The embryos grew for 8.5 days, long enough for them to develop distinct organs — a beating heart, a gut tube and even neural folds.

Cities embrace their water — and build resilience

Briony Rogers helps cities to connect to their environment to better survive drought and storm surges.

Nature | August 17, 2022

An infiltration basin at the White Gum Valley development in Perth, Australia, manages stormwater runoff and provides shade.Credit: The Cooperative Research Centre for Water Sensitive CIties

“When we think about making decisions on how we shape our cities, that deep connection and stewardship of water is really important,” says Briony Rogers, a civil engineer at the Monash Sustainable Development Institute and director of MSDI Water, the institute’s water research hub in Melbourne, Australia.

Rogers’ work on ‘water-sensitive’ cities brings together her interest in applying civil engineering to shape the environment humans live in, and her love of the beaches and forests that surround her in Melbourne.

That interest began when she worked as a water engineer at a design infrastructure company and realized that, to create truly sustainable infrastructure, principles of sustainability needed to be incorporated from the very start of the design process.