At a University of Maryland lab, people infected with the new coronavirus take turns sitting in a chair and putting their faces into the big end of a large cone. They recite the alphabet and sing or just sit quietly for a half hour. Sometimes they cough.
The cone sucks up everything that comes out of their mouths and noses. It's part of a device called "Gesundheit II" that is helping scientists study a big question: Just how does the virus that causes COVID-19 spread from one person to another?
It clearly hitchhikes on small liquid particles sprayed out by an infected person. People expel particles while coughing, sneezing, singing, shouting, talking and even breathing. But the drops come in a wide range of sizes, and scientists are trying to pin down how risky the various kinds are.
The answer affects what we should all be doing to avoid getting sick. That's why it was thrust into headlines a few days ago when a US health agency appeared to have shifted its position on the issue, but later said it had published new language in error.
The recommendation to stay at least 6 feet (2 meters) apart — some authorities cite about half that distance — is based on the idea that larger particles fall to the ground before they can travel very far. They are like the droplets in a spritz of a window cleaner, and they can infect somebody by landing on their nose, mouth or eyes, or maybe being inhaled.
But some scientists are now focusing on tinier particles, the ones that spread more like cigarette smoke. Those are carried by wisps of air and even upward drafts caused by the warmth of our bodies. They can linger in the air for minutes to hours, spreading throughout a room and build up if ventilation is poor.
The potential risk comes from inhaling them. Measles can spread this way, but the new coronavirus is far less contagious than that.
For these particles, called aerosols, "6 feet is not a magic distance,'' says Linsey Marr, a leading researcher who is studying them at Virginia Tech in Blacksburg. But she says it's still important to keep one's distance from others, "the farther the better," because aerosols are most concentrated near a source and pose a bigger risk at close range.
Public health agencies have generally focused on the larger particles for coronavirus. That prompted more than 200 other scientists to publish a plea in July to pay attention to the potential risk from aerosols. The World Health Organization, which had long dismissed a danger from aerosols except in the case of certain medical procedures, later said that aerosol transmission of the coronavirus can't be ruled out in cases of infection within crowded and poorly ventilated indoor spaces.
The issue drew attention recently when the US Centers for Disease Control and Prevention posted and then deleted statements on its website that highlighted the idea of aerosol spread. The agency said the posting was an error, and that the statements were just a draft of proposed changes to its recommendations.
Dr Jay Butler, CDC's deputy director for infectious disease, told AP that the agency continues to believe larger and heavier droplets that come from coughing or sneezing are the primary means of transmission.
Last month Butler told a scientific meeting that current research suggests aerosol spreading of the coronavirus is possible but it doesn't seem to be the main way that people get infected. Further research may change that conclusion, he added, and he urged scientists to study how often aerosol spread of the coronavirus occurs, what situations make it more likely and what reasonable steps might prevent it.
Marr said she thinks infection by aerosols is "happening a lot more than people initially were willing to think."
As a key piece of evidence, Marr and others point to so-called "superspreader" events where one infected person evidently passed the virus to many others in a single setting.
In March, for example, after a choir member with coronavirus symptoms attended a rehearsal in Washington state, 52 others who had been seated throughout the room were found to be infected and two died. In a crowded and poorly ventilated restaurant in China in January, the virus evidently spread from a lunchtime patron to five people at two adjoining tables in a pattern suggesting aerosols were spread by the air conditioner. Also in January, a passenger on a Chinese bus apparently infected 23 others, many of whom were scattered around the vehicle.
Butler said such events raise concern about aerosol spread but don't prove it happens.
There could be another way for tiny particles to spread. They may not necessarily come directly from somebody's mouth or nose, says William Ristenpart of the University of California, Davis. His research found that if paper tissues are seeded with influenza virus and then crumpled, they give off particles that bear the virus. So people emptying a wastebasket with tissues discarded by somebody with COVID-19 should be sure to wear a mask, he said.
Scientists who warn about aerosols say current recommendations still make sense.
Wearing a mask is still important, and make sure it fits snugly. Keep washing those hands diligently. And again, staying farther apart is better than being closer together. Avoid crowds, especially indoors.
Their main addition to recommendations is ventilation to avoid a buildup of aerosol concentration. So, the researchers say, stay out of poorly ventilated rooms. Open windows and doors. One can also use air-purifying devices or virus-inactivating ultraviolet light.
Best of all: Just do as much as you can outdoors, where dilution and the sun's ultraviolet light work in your favor.
"We know outdoors is the most spectacularly effective measure, by far,'' says Jose-Luis Jimenez of the University of Colorado-Boulder. "Outdoors it is not impossible to get infected, but it is difficult."
The various precautions should be used in combination rather than just one at a time, researchers say. In a well ventilated environment, "6 feet (of separation) is pretty good if everybody's got a mask on" and nobody stays directly downwind of an infected person for very long, says Dr. Donald Milton of the University of Maryland School of Public Health, whose lab houses the Gesundheit II machine.
Duration of exposure is important, so there's probably not much risk from a short elevator ride while masked or being passed by a jogger on the sidewalk, experts say.
Scientists have published online tools for calculating risk of airborne spread in various settings.
At a recent meeting on aerosols, however, Dr. Georges Benjamin, executive director of the American Public Health Association, noted that preventive steps can be a challenge in the real world. Keeping apart from other people can be difficult in homes that house multiple generations. Some old buildings have windows that were "nailed shut years ago," he said. And "we have far too many communities where they simply don't have access to clean water to wash their hands."
It might seem strange that for all the scientific frenzy to study the new coronavirus, the details of how it spreads can still be in doubt nine months later. But history suggests patience.
"We've been studying influenza for 102 years," says Milton, referring to the 1918 flu epidemic. "We still don't know how it's transmitted and what the role of aerosols is."
Two officers were shot and wounded on Wednesday night as people protest in Louisville in US, hours after a Kentucky grand jury brought no charges against Louisville police for Breonna Taylor's death.
Interim Louisville Police Chief Robert Schroeder said both officers are expected to recover, and one is undergoing surgery, reports AP.
A suspect was in custody but did not offer details about whether that person was participating in the demonstrations, he said.
He says the officers were shot after investigating reports of gunfire at an intersection where there was a large crowd.
Several shots rang out as protesters in downtown Louisville tried to avoid police blockades, moving down an alleyway as officers lobbed pepper balls, according to an Associated Press journalist.
People covered their ears, ran away and frantically looked for places to hide. Police with long guns swarmed the area, then officers in riot gear and military-style vehicles blocked off roadways.
The violence comes after prosecutors said two officers who fired their weapons at Taylor, a Black woman, were justified in using force to protect themselves after they faced gunfire from her boyfriend.
The only charges were three counts of wanton endangerment against fired Officer Brett Hankison for shooting into a home next to Taylor's with people inside.
The FBI is still investigating potential violations of federal law in connection with the raid at Taylor's home on March 13.
Ben Crump, a lawyer for Taylor's family, denounced the decision as “outrageous and offensive,” and protesters shouting, “No justice, no peace!” immediately marched through the streets.
Scuffles broke out between police and protesters, and some were arrested.
Officers fired flash bangs and a few small fires burned in a square that's been at the center of protests, but it had largely cleared out ahead of a nighttime curfew as demonstrators marched through other parts of downtown Louisville. Dozens of patrol cars blocked the city’s major thoroughfare and more police arrived after the officer was shot.
Demonstrators also marched in cities like New York, Chicago, Washington, D.C., Atlanta and Philadelphia.
State Attorney General Daniel Cameron, however, said the investigation showed the officers announced themselves before entering. The warrant used to search her home was connected to a suspect who did not live there, and no drugs were found inside.
Along with the killing of George Floyd in Minnesota, Taylor’s case became a major touchstone for nationwide protests that have drawn attention to entrenched racism and demanded police reform. Taylor’s image has been painted on streets, emblazoned on protest signs and silk-screened on T-shirts worn by celebrities. Several prominent African American celebrities joined those urging that the officers be charged.
The announcement drew sadness, frustration and anger that the grand jury did not go further. The wanton endangerment charges each carry a sentence of up to five years.
A fourth Phase 3 clinical trial evaluating an investigational Covid-19 vaccine has begun enrolling adult volunteers, the U.S. National Institutes of Health (NIH) announced on Wednesday.
The trial is designed to evaluate if the investigational Janssen Covid-19 vaccine JNJ-78436725 can prevent symptomatic COVID-19 after a single dose regimen, the NIH said in a release, reports Xinhua.
Up to 60,000 volunteers will be enrolled in the trial at up to nearly 215 clinical research sites in the United States and internationally.
The Janssen Pharmaceutical Companies of Johnson & Johnson developed the investigational vaccine, and is leading the clinical trial as regulatory sponsor.
It is the fourth large-scale phase 3 clinical trials for a Covid-19 vaccine in the United States.
The other three trials are for vaccine candidate AZD1222, co-invented by the University of Oxford and its spin-out company Vaccitech; vaccine candidate mRNA-1273, developed by the U.S. National Institute of Allergy and Infectious Diseases (NIAID) and American biotechnology company Moderna; and vaccine candidate BNT162b2, developed by American biopharmaceutical company Pfizer and German company BioNTech.
While the other vaccine candidates require two doses, the Janssen vaccine candidate will be studied as a single-dose vaccine. It is a recombinant vector vaccine that uses a human adenovirus to express the SARS-CoV-2 spike protein in cells.
Preclinical findings published in Nature show that the Janssen vaccine induced neutralizing antibody responses in rhesus macaques and provided complete or near-complete protection against virus infection in the lungs and nose following SARS-CoV-2 challenge.
The trial is designed primarily to determine if the investigational vaccine can prevent moderate to severe Covid-19 after a single dose. It also aims to understand if the vaccine can prevent Covid-19 requiring medical intervention and if the vaccine can prevent milder cases of Covid-19 and asymptomatic SARS-CoV-2 infection, according to the NIH.
An independent Data and Safety Monitoring Board will provide oversight to ensure the safe and ethical conduct of the study.
"Four Covid-19 vaccine candidates are in Phase 3 clinical testing in the United States just over eight months after SARS-CoV-2 was identified. This is an unprecedented feat for the scientific community made possible by decades of progress in vaccine technology and a coordinated, strategic approach across government, industry and academia," said NIAID Director Anthony Fauci.
"It is likely that multiple Covid-19 vaccine regimens will be required to meet the global need. The Janssen candidate has showed promise in early-stage testing and may be especially useful in controlling the pandemic if shown to be protective after a single dose," Fauci said.
President Donald Trump on Tuesday demanded that the United Nations hold China accountable for the coronavirus pandemic as he defends his own handling of COVID-19 in America where the death toll is nearing 200,000.
"We have waged a fierce battle against the invisible enemy – the China virus – which has claimed countless lives in 188 countries," Trump said in a prerecorded address to the UN General Assembly that lasted less than seven minutes.
"As we pursue this bright future, we must hold accountable the nation which unleashed this plague onto the world: China."
While Trump blames China, he has been harshly criticized for his administration's track record in battling the coronavirus, now a top issue in his bid for reelection. Democratic opponent Joe Biden claims Trump bungled the response to COVID-19 and is responsible for the US having more deaths than any other nation.
Trump encouraged the reopening of US society even as the virus was spreading rapidly and holds campaign rallies where few wear face masks or practice social distancing.
But Trump points to the virus' origins in China and says the Chinese government acted irresponsibly in allowing the virus to spread.
"The United Nations must hold China accountable for their actions," Trump said. The president also took aim at China's environmental record and the United Nations itself.
"Those who attack America's exceptional environmental record while ignoring China's rampant pollution are not interested in the environment. They only want to punish America. And I will not stand for it," Trump said.
Tropical Storm Beta stalled out Tuesday along the Texas coast, flooding streets in Houston and Galveston hours after making landfall amid an unusually busy hurricane season.
The storm made landfall late Monday just north of Port O’Connor, Texas, and has the distinction of being the first time a storm named for a Greek letter made landfall in the continental United States. Forecasters ran out of traditional storm names last week, forcing the use of the Greek alphabet for only the second time since the 1950s.
Early Tuesday, Beta was 10 miles (15 kilometers) east-southeast of Victoria, Texas, with maximum winds of 40 mph (64 kph), the U.S. National Hurricane Center said. The storm was moving toward the northwest near 3 mph (4 kilometers) and is expected to stall inland over Texas through Wednesday.
“We currently have both storm surge and rainfall going on right now,” said National Weather Service meteorologist Amaryllis Cotto in Galveston, Texas.
Cotto said 6-12 inches (15-30 centimeters) of rain has fallen in the area, with isolated amounts of up to 18 inches (45 centimeters). Dangerous flash flooding is expected through Wednesday, Cotto said.
Beta was the ninth named storm that made landfall in the continental U.S. this year. That tied a record set in 1916, according to Colorado State University hurricane researcher Phil Klotzbach.
Beta was expected to linger over Texas then eventually move over Louisiana, Arkansas and Mississippi later in the week, bringing the risk of flash flooding.
Forecasters warned of heavy rainfall Tuesday on the middle and upper Texas coast, which will cause significant flash flooding. Six to 12 inches of rain (15 to 30 centimeters) was expected, with some isolated areas of up to 20 inches (51 centimeters), forecasters said.
However, forecasters and officials reassured residents Beta was not expected to be another Hurricane Harvey or Tropical Storm Imelda.
Harvey in 2017 dumped more than 50 inches (127 centimeters) of rain on Houston, causing $125 billion in damage in Texas. Imelda, which hit Southeast Texas last year, was one of the wettest cyclones on record.
Storm surge up to 4 feet (1.2 meters) was possible in the Galveston and Beaumont areas through Wednesday morning, forecasters said. In Galveston, an island city southeast of Houston, there was already some street flooding Monday from rising tides and part of a popular fishing pier collapsed due to strong waves.
Farther south on the Texas coast, Maria Serrano Culpepper along with her two daughters and dogs left their home in Magnolia Beach near Matagorda Bay on Sunday night.