Francesco Carta photographer / Getty Images
When Linsey Marr looks back at the beginning of 2020, what strikes her is how few people in the world really understood how viruses can travel through the air.
“In the last year, we have come a long way in understanding airborne transmission, or at least a little beyond just the few experts studying it, than we have for decades,” says Marr. “Honestly, I thought it would take us another 30 years to get to where we are now.”
The urgency of the coronavirus pandemic threw her once obscure field into the spotlight, as everyone from public health experts to ordinary citizens tried to measure the safety of countless activities such as going to the grocery store, swimming on the beach or gathering for a party.
“Back in January, understanding how viruses spread through the air was really primitive and incorrect,” said Marr, a researcher at Virginia Tech who has spent years studying virus transmission. “It has been quite wild to see the transmission of viruses in the air become big news.”
At the onset of this coronavirus outbreak, the prevailing assumption among many medical experts was that the respiratory virus mainly spread through saliva and mucus that flies into the air after coughing or sneezing. These were thought to travel only a short distance before falling to a surface. Public health reports therefore urged people to wash their hands and avoid touching their faces.
Coronavirus was not thought to be “airborne”, a word associated with viruses that causes measles. An airborne virus was widely considered to be a bacterium that could move in small particles called aerosols that hang suspended in the air and linger for a while, potentially traveling long distances.
But in reality, there is no clear distinction between a virus that moves in aerosols and one that moves in larger droplets, says Marr. Infected people can emit respiratory viruses in particles of all different sizes that can move over different distances, and large droplets can evaporate into small ones. Very close to an infected person, the concentration of airborne virus can be high, and others can just inhale it.
When the new coronavirus began to spread, it certainly seemed that airborne spread – at a short distance – could be critical.
“Once it became clear that this was a very important route for transmission, you know, I and others started making noise about this,” said Marr, who sent out a Tweet in early March saying “Let’s talk about airborne transmission. of SARSCOV2 and other viruses. A discussion is needed to improve the accuracy and reduce the fear associated with the term. ”
Let’s talk about # airborne transmission of # SARSCOV2 and other viruses. A discussion is needed to improve the accuracy and reduce the fear associated with the term. / 1
– Linsey Marr (@linseymarr) March 5, 2020
Meanwhile, scientific research on how the COVID-19 virus moves through the air was done at an astonishingly fast pace.
“We are not even 12 months in, and we know things about this virus that we do not know about viruses that have been around for decades,” said Josh Santarpia, a researcher at the University of Nebraska Medical Center.
He notes that no one has been able to grow measles virus from an air sample, and yet some insisted that this type of evidence was needed before saying that the new coronavirus could be airborne.
“It was interesting that the burden of proof was so high for this virus when it was not for these other things that we just consider to be airborne,” says Santarpia.
His medical center cared for some of the first coronavirus people in the United States, and Santarpia remembers standing at the end of their beds with a device that collected air while talking or breathing. His laboratory then analyzed the small airborne droplets and looked for the genetic signature of the coronavirus.
“We got positive, more than one positive in the air samples,” says Santarpia. “I was shocked.” Signs of the virus were in such small particles, he worried that nothing less than the most protective masks could stop it.
However, studies showed that even simple masks were able to reduce the amount of virus released into the air, reducing the risk of transmission. Mask use suddenly became a common – albeit politically controversial – part of everyday life.
Santarpia got a floor over how quickly ventilation became a common topic of conversation for the public.
“You know,” How well ventilated is this room? Should I spend time indoors or outdoors? “” says Santarpia. “So much has changed about the way we look at the world.”
Whether this will be a lasting change is an open question.
Donald Milton, a researcher at the University of Maryland, has spent a quarter of a century thinking about transmitting the respiratory virus through the air, and has published studies showing that better ventilation in offices and dormitories is associated with a lower risk of virus transmission.
He hopes the experience over the past year will lead to better engineering solutions in place to improve the overall safety of houses and other indoor spaces: things like improved ventilation, air filters or the use of special lights up in the ceiling of the room to disinfect air circulation.
“How can we make indoor areas safe so that we can keep the economy going and fight a pandemic without all the damage we see from the interventions we are forced to take this year?” says Milton. “I want to see us understand what it is like to make a restaurant a safe place to be in a flu season and during a pandemic.”
He thinks it is feasible, but he is worried that when vaccines get coronavirus in check, people will just lose interest – until the next time there is a new virus that can be transmitted through the air.