More young people are being infected with the coronavirus, and even though they're less likely to die from it, experts warn the virus' wide and rapid spread among young adults may further fuel outbreaks across the U.S.

Why it matters: Some people in their 20s and 30s face serious health complications from COVID-19, and a surge in cases among young people gives the virus a bigger foothold, increasing the risk of infection for more vulnerable people.

• "We may see a pattern of younger people being affected initially, but then, in a number of weeks from now, we’re going to see a more deadly pandemic spreading to elderly people," says Alison Galvani, an epidemiologist at Yale University.

People can transmit the virus without knowing they have it, and younger people, in particular, could be unknowingly spreading the disease.

• A study in Italy, yet to be peer reviewed, found the probability of having symptoms increased with age and that among 20-39-year-olds only about 22% had a fever or respiratory symptoms (compared with about 35% of 60-79-year-olds).
• About half of the clusters in a study in Japan were traced back to people 20-39 years old at karaoke bars, offices and restaurants — and 41% of them did not have symptoms at the time.
• "Younger people are at lower risk for serious COVID outcomes but are disproportionately responsible for asymptomatic transmission," says Galvani, who published a study earlier this week that found the majority of COVID-19 transmission is from silent carriers who are pre-symptomatic or asymptomatic.

By the numbers: From Arizona to Allegheny County, Pa., young people increasingly account for COVID-19 cases.

• In L.A. County, nearly 50% of cases are now in people under 40 (compared to about 30% in April), per the LA Times.
• In Harris County, Texas, home to Houston, 43% of the 40,000 cases are in people ages 20-39.
• In Florida, the median age of confirmed cases is hovering in the mid- to late-30s, compared to age 65 in March.

And the proportion of young people hospitalized for COVID-19 has also grown.

Between the lines: Yes, young people are going to bars and parties — but also to work.

• There's a need for better education so that young people choose to take steps to prevent infection but also for policies that get employers to provide safe workplaces, says Lauren Ancel Meyers, a mathematical epidemiologist at the University of Texas at Austin.

Where it stands: Young people are still much less likely to be hospitalized or die from the virus than people older than 60.

• Yes, but: They can and do get very sick with the disease — from dangerous blood clots in their lungs to inflammation of the heart, lungs and even brain. And the long-term consequences are unknown.
• The risk is higher for young people of color: for example, the majority of coronavirus hospitalizations among Latino/Hispanic Americans are for people ages 18-49, my Axios colleague Caitlin Owens reported.

"The death rate among the young is not zero, and it is particularly not zero for people who have at least one co-morbid condition. This is not a completely benign disease of the young."

What to watch: "If hospitals are strained now dealing with younger cases, they are going to be all the more taxed when the age distribution of infections shifts to the elderly," says Galvani.

• Already hospitals in some states are hitting their capacity of ICU beds, indicating more vulnerable people are being infected, and the death rate is climbing in hot spots.

Go deeper.

Thirty-three states saw their caseloads increase this week, continuing a scary nationwide trend that’s been getting worse since mid-June, my colleagues Sam Baker and Andrew Witherspoon report.

Why it matters: The U.S. is right back in the situation we were afraid of earlier this year, with a rapidly spreading outbreak, strained hospitals and projections of more than 200,000 deaths by the end of the year.

What we’re watching: New coronavirus cases surged over the past week in places that were already heading quickly in the wrong direction.

• That includes Arizona (a 23% jump over the past week), California (38%), Florida (25%) and Texas (28%). All of those states have experienced dramatic increases for several weeks in a row, and those cases are now threatening to overwhelm some local hospitals.

Those worsening conditions across the board make clear that these numbers largely are not a product of increased testing but rather a worsening outbreak.

• Nationwide, testing increased by 7% over the past week. Cases rose by 24%.

The spillover of pathogens from animals to humans — driven mainly by human behaviors like urbanization and the demand to eat meat — is increasing and will continue wreaking havoc unless global action is taken, Axios' Eileen Drage O'Reilly reports.

Driving the news: The United Nations Environment Programme issued a report this week outlining steps to prevent spillovers and encouraging governments to adopt a "One Health" approach to humans, animals and the environment.

What can be done: Several scientific experts tell Axios global surveillance is one of the big first steps to prevention.

1. Track wildlife and livestock to catch pathogens before they spread to humans.

• One suggestion is reinstating PREDICT, a federally funded program designed to hunt down new pandemic pathogens globally that was shut down in 2019 just before the COVID-19 pandemic, despite its now-prescient warnings. A USAID spokesperson told the L.A. Times there would be a new initiative to stop the spillover of viruses from animals to humans, awarded in August.
• Another could be "a more cost-effective, decentralized disease surveillance system" that empowers local wildlife and public health professionals to test for diseases year round, at the source, according to a proposal published in Science today by the Wildlife Disease Surveillance Focus Group.

2. Fund and facilitate new technologies that can provide efficient, less costly and consistent testing, even in remote areas.

• "There is a scarcity of genetic and genomic research technologies within the conservation world and within ecology, at a lot of these really biodiverse regions. And we think that this decentralized model can really bring that technology to those areas," says Caroline Moore, a fellow with San Diego Zoo Global in disease investigations and part of the focus group.

3. Develop global databases to first track what's happening in wildlife and then eventually with humans.

• Mrinalini Erkenswick Watsa, another focus group member and researcher for the Institute for Conservation Research, says they hope to establish a wildlife database similar to the GISAID initiative, originally designed to track influenza but now also focused on COVID-19.

Go deeper.

A coalition of AI groups is forming to produce a comprehensive data source on the coronavirus pandemic for policymakers and health care leaders, Axios' Bryan Walsh reports.

Why it matters: A torrent of data about COVID-19 is being produced, but unless it can be organized in an accessible format, it will do little good. The new initiative aims to use machine learning and human expertise to produce meaningful insights for an unprecedented situation.

Driving the news: Members of the newly formed Collective and Augmented Intelligence Against COVID-19 (CAIAC) announced today include the Future Society, a nonprofit think tank from the Harvard Kennedy School of Government, as well as the Stanford Institute for Human-Centered Artificial Intelligence and representatives from the United Nations.

• Within six to eight weeks, CAIAC's platform will produce a decision-making tool that will initially focus on digital contact tracing of coronavirus infections, ferreting out misinformation about the pandemic, and identifying second- and third-order effects of COVID-19 that go beyond illness and death.

What they're saying: "With COVID-19 we realized there are tons of data available, but there was little global coordination on how to share it," says Cyrus Hodes, chair of the AI Initiative at the Future Society and a member of the CAIAC steering committee.

• Hodes says CAIAC will be targeting U.N. agencies as some of the first users for the platform.

Context: COVID-19 has produced a flood of statistics, data and scientific publications — more than 35,000 of the latter as of July 8. But raw information is of little use unless it can be organized and analyzed in a way that can support concrete policies.

• CAIAC will join similar initiatives like C3.ai's COVID-19 data lake and the Allen Institute for AI's CORD-19 data set.
• "We want these tools to exist as a legacy for policymakers worldwide to use when the next crisis comes," says Hodes. "COVID-19 won't be the last grand challenge we face."

Fighting the coronavirus infodemic (Bryan Walsh — Axios)

China’s massive effort to collect its people’s DNA concerns scientists (David Cyranoski — Nature News)

Native Americans crossed the Pacific long before Europeans (Abby Olena — The Scientist)

New evidence shows editing human embryos wreaks havoc on DNA (Emily Mullin — OneZero)

Meadows of seagrass on the ocean floor are among the planet's most efficient ecosystems for absorbing and storing carbon.

Why it matters: Climate change, industrial and agricultural run-off, and development along coastlines are threatening the world's seagrass meadows.

• About 161,150 hectares of seagrass have been lost along Australia's coasts since the 1950s, releasing carbon dioxide equivalent to that from 5 million cars each year, according to new research.

What they did: Cristian Salinas of Edith Cowan University and his colleagues compared carbon stored in the sediment of seagrass meadows with areas that no longer had seagrass in western Australia's Cockburn Sound.

• A loss of seagrass by itself didn't account for the carbon dioxide emitted from the soil, the researchers report in the journal Global Change Biology.
• Waves, tides and currents disrupted the soil and sand in shallow areas without seagrass, releasing the carbon sequestered in it.
• They also found seagrass meadows in shallow water stored more carbon than those in deep water, making the nearshore an important area to preserve, Salinas notes.

The big picture: Seagrass meadows — made up of more than 70 species of the marine flowering plant — filter seawater, buffer ocean acidification, regulate carbon and are home to more than 20% of the world's largest fisheries.

• "In one square meter is the same amount of carbon that can be sequestered in 30-40 square meters of forest," says Salinas.
• About 7% of the habitat is lost each year, contributing up to 299 Tg of carbon to the atmosphere, according to a June report from the U.N. Environment Programme.
• The U.N. and others are urging countries to preserve and restore seagrass as one way to address climate change.