COVID-19 is the first major pandemic in the social media era — offering experts a rare opening to study the relationship between online misinformation and human behavior on a large scale, my colleague Sara Fischer and I write.

Why it matters: As misinformation about COVID-19 vaccines runs rampant, researchers are trying to measure how much memes and messages with false information can alter someone's decision to get vaccinated.

What's happening: Daily COVID-19 vaccinations in the U.S. have slowed over the past month, and those remaining Americans are less enthusiastic about being vaccinated, suggesting the country is hitting a vaccine wall.

• "There is mounting evidence that exposure to certain types of media is associated with hesitancy," says Kayla de la Haye, who studies social networks and their impact on health and disease prevention at the University of Southern California.
• Tech platforms are scrambling to deal with vaccine disinformation, but experts argue they may be too late and misinformation is persisting.

Details: Researchers at Indiana University's Observatory on Social Media found states where a higher percentage of discussions on Twitter included low-credibility sources also tended to have a higher percentage of people who are hesitant to get vaccinated.

• In another study, published earlier this year, knowledge and misinformation emerged as key predictors of whether someone intended to get vaccinated.

Yes, but: It's really hard to connect exposure to misinformation to behaviors, says de la Haye.

• "There's a recognition this is a big problem, but it's a problem that's part of a complicated set of factors that influence whether someone gets vaccinated," she says.
• A person's political affiliation, assessment of their own risk of disease, access to vaccines, technology and transportation, and socioeconomic status are also factors, many of which are interconnected.

The big picture: One word dominates the reasons people give for being hesitant or resistant to getting a COVID-19 vaccine: trust, says David Lazer of Northeastern University who, with his collaborators, has conducted dozens of surveys over the past year to study people's attitudes and behaviors during the pandemic.

• A lack of trust in government, companies or institutions may be why some people accept misinformation and even actively seek it, and why they're skeptical of getting vaccinated, he says.

What to watch ... the roughly 30 million Americans who aren't saying they won't get a vaccine or are waiting but say they'll do it when they can.

• Some people who are considered hesitant are trying to make an informed decision while encountering a wave of disinformation, says Samuel Scarpino, a business professor of network science at Northeastern University College of Science.
• "I’m skeptical that reaching them is by convincing Facebook to remove misinformation and more about taking vaccines out to people and reducing the friction of 'I can’t be bothered,'" Scarpino says, pointing to efforts to vaccinate people on the New York City subway, at baseball games and in churches.

The bottom line: "Even if there isn’t a whole lot we can do about fighting misinformation or backing out its individual contribution to hesitancy, it doesn’t mean there isn’t a whole lot else we can do," Scarpino says.

Read the full story.

"The U.S. averaged fewer than 40,000 new cases per day over the past week," Axios' Sam Baker and Andrew Witherspoon report.

Fully vaccinated people don't need to wear masks indoors in most cases, the CDC said today.

A SARS-CoV-2 variant first detected in India is a global "variant of concern," the World Health Organization said Monday. Preliminary studies suggest B.1.617 may be more transmissible than other variants, per the WSJ.

Pfizer-BioNTech's COVID-19 vaccine was authorized for use in people ages 12–15, Axios' Shawna Chen and Marisa Fernandez report.

"The COVID-19 pandemic was a 'preventable disaster' that exposed weak links 'at every point' of the preparedness process, according to a World Health Organization-commissioned report published Wednesday," per Axios' Ivana Saric.

As the participant imagined writing a letter, sensors implanted in his brain picked up on patterns of electrical activity, which an algorithm interpreted to trace the path of his imaginary pen. Credit: F. Willett et al./Nature 2021.

The imagined handwriting of a person with paralysis can be translated into text through a brain–computer interface (BCI) that was faster than other types of assistive communication, Axios' Eileen Drage O'Reilly reports.

Why it matters: While the interface was only tested in one person and is a proof-of-concept finding, some experts say it's an "important milestone" in developing the technologies needed by millions of people globally who've lost the ability to use their upper limbs or the ability to speak due to paralysis, strokes or Lou Gehrig's disease.

Details: The team of researchers, whose trial is part of an international collaboration called BrainGate2, implanted electrodes on the surface of the brain of the participant (who is paralyzed from the neck down) to study the complex patterns of neural activity used when visualizing the task of handwriting individual letters.

• They were able to decode the electrical activity from about 200 different neurons into a prediction of what letter the person was wanting to make, says study co-author Krishna Shenoy, a professor of engineering at Stanford University.

What they found: The participant was able to compose sentences and communicate at a rate of about 90 characters per minute with a 94% raw accuracy and 99% accuracy with autocorrect, according to the results published in Nature.

• This compares with existing communication BCIs that use the brain to "point and click" on letters at a pace of about 40 characters per minute.

What they're saying: Jennifer Collinger, associate professor at the University of Pittsburgh's Rehab Neural Engineering Lab who was not part of this study, says the findings are "exciting and interesting" for several reasons.

• One is that from a practical communications standpoint, the new technique appears to double the current rate of assistive communications, Collinger says.
• "But, more than that, I would not have thought to try to decode handwriting. It seems like a very challenging problem: How is that going to be better than accessing an onscreen keyboard that people have been working towards for decades? The fact they were able to achieve such a high level of performance is really, really interesting," she says.

What we're watching: "The future really is — as we learn more and more about the brain — [that] we should be able to interact with it and help overcome dysfunction as well as to understand how it normally functions," Shenoy says.

Satellites are ushering in a new era of environmental accountability (Miriam Kramer and Andrew Freedman — Axios)

New White House panel aims to separate science, politics (Seth Borenstein — AP)

The night the zoo burned (Ben Crair — New Yorker)

Blind patients hope landmark gene-editing experiment will restore their vision (Rob Stein — NPR)

Diamonds are one of the few ways scientists can access the deep Earth and our planet's history.

What's new: Researchers this week report they can measure the age of fluids trapped in a diamond, chemical messages about Earth's evolution.

How it works: Most diamonds form between 150 km and 200 km below the surface and were brought up by volcanic eruptions.

• Gem-quality diamonds are pure carbon, which doesn't carry much information.
• But lower-quality, fibrous, or "dirty" diamonds are gems in their own right for geologists because they contain inclusions or impurities from the surroundings where diamonds are formed.
• "Whatever was encapsulated inside them stays pristine for billions of years," says study co-author Yaakov Weiss of Columbia University's Lamont-Doherty Earth Observatory and the Hebrew University of Jerusalem.

What they found: Weiss and his co-authors measured the amount of thorium and uranium in fluid trapped in 10 diamonds from South Africa. They then looked at these levels relative to helium-4, which is produced as the radioactive thorium and uranium decay.

• A key advance, though, was that the team also measured how fast helium diffused out of the diamonds, which influences the ratio calculated and the dating of the diamond's age.

The big picture: The researchers then used the measurements to try to connect the diamonds' formation with the geological history of South Africa.

• During the earliest period — 2.6 billion to 700 million years ago, inclusions were full of carbonate, possibly a reflection of the formation of mountains on Earth's surface at the same time or connected to older events, the researchers write in Nature Communications this week.
• Impurities rich in silica were dated to 540 million to 300 million years ago.
• Sodium and potassium were found in elevated amounts in inclusions formed 130 million to 85 million years ago, suggesting the source of carbon for the diamonds changed, possibly coming from an ocean floor pulled beneath the surface. The end of this period is also the time when the diamonds were likely pushed to the Earth's surface by eruptions.

What they're saying: Fibrous diamonds were thought to be young, but the new research shows they grew way before magma brought them to the surface, says Suzette Timmerman, who studies diamonds as a postdoctoral fellow at the University of Alberta and wasn't involved in the new study.

• "Diamonds are forever. Now we can see that these fibrous diamonds can be really old as well."