CHICAGO — It’s been only nine months since the world learned of a new coronavirus that would trigger a pandemic declaration in March and ultimately disrupt billions of lives.
That’s little more than a blink of the eye when it comes to understanding a novel disease, and the advice from scientists and doctors is still evolving as they accumulate experience with COVID-19.
“People seem to think that we would have all the information on it right away,” said Northwestern University professor Aaron Packman, an environmental engineer who specializes in surveillance of wastewater and buildings to detect disease-causing germs. “What most people don’t appreciate is when you have a new disease — a new infectious disease, a new pathogen — historically it’s taken years to get all the information you need to fully deal with it. This is all accelerated, a lot.”
Here are some things that science has learned — so far — about the SARS-CoV-2 coronavirus and the disease it causes.
1. The disease spreads primarily through the air.
Early advice on how to protect oneself from COVID-19 focused a great deal on surfaces, after initial studies found that SARS-CoV-2 can survive on surfaces for two or three days.
That led to an early public health focus on frequent hand-washing, disinfecting surfaces and groceries, and telling people to “stop touching your face.”
But as epidemiologists watched the pandemic unfold, evidence emerged about the disease spreading in crowded rooms — especially at bars, restaurants and churches — suggesting that airborne virus particles were the main cause of transmission.
While hand-washing and cleaning surfaces are still good practices, the primary focus has shifted to mask-wearing and maintaining social distance.
2. Wearing a mask helps prevent the virus from spreading.
In the days leading up to the pandemic declaration on March 11, national public health officials were saying people didn’t need to wear a mask, in some cases contending masks weren’t effective at preventing COVID-19 transmission.
But in April, the Centers for Disease Control and Prevention changed course and recommended that people wear a cloth face covering when distance from others could not be maintained.
The early advice was based on a lack of understanding about how COVID-19 spreads and the fear that a run on medical-grade masks would place health care workers in danger at a time when protective gear was in short supply.
But it soon became clear the virus was spreading via particles exhaled from the mouths and noses of infected people. And early experiments involving cloth face coverings suggested they could reduce the amount that escapes into the air. That, in turn, limits how much of the virus is inhaled by others nearby, which can prevent infection or reduce the severity of the disease.
“The truth was that we didn’t know how effective fabric masks were or were not, or are or are not. We know now,” said Dr. Emily Landon, executive medical director of infection prevention and control at University of Chicago Medicine.
Dr. Rahul Khare, CEO of the Innovative Express Care immediate care facility in Chicago and an early advocate of mask use, said he’s heartened that so many people have adopted mask-wearing in public.
“It has become a cultural norm to have a mask on when outdoors or when even in your office space, which three months ago would be crazy,” Khare said. “And we actually feel uncomfortable when we see someone or talk with someone who does not have a mask. So I think that’s pretty remarkable.”
3. Six feet apart sometimes isn’t far enough.
By now, people are very familiar with the advice to maintain a “social distance” of 6 feet.
That guidance is based on the idea that the respiratory droplets emitted while talking, singing or coughing fall to the ground relatively quickly and don’t travel far.
But it isn’t just the droplets we have to worry about, experts now say. Researchers have found the virus also can be present in much smaller particles called aerosols that are lighter, linger in the air longer and can spread much farther.
“In the beginning, we thought this was going to be a droplet-borne infection,” said Landon. Two other diseases caused by coronaviruses, SARS and MERS, “are entirely droplet-borne,” she said. “And the ordinary coronavirus that causes colds we get every year is mostly droplet-spread, and we don’t see a lot of airborne spread.”
The new knowledge about aerosols has put a wrinkle in the 6-foot rule. Outdoors, where fresh air rapidly disperses the virus, 6 feet is likely enough space between people who aren’t wearing masks, but people should wear masks indoors even if they are 6 feet apart, Landon said.
Scientists are also turning their focus to improving the ventilation of indoor spaces and looking at ways to kill the airborne virus inside buildings.
4. People without symptoms can transmit COVID-19, giving rise to the term “silent spreaders.”
The spread of COVID-19 primarily by air is especially concerning in light of another unexpected behavior of SARS-CoV-2: It can infect someone and cause no symptoms, and people can be infected for weeks before symptoms do emerge. That means people can be spreading infected droplets and aerosols and not know it.
“The toughest thing about this virus seems to be that there’s quite a prolonged incubation period,” said Dr. Sadiya Sana Khan, an epidemiologist at Northwestern University Medical Center who specializes in cardiac care. “Typically, in influenza, you’ll have symptoms in a day or two. Here, the average end of the median time is five days. That’s a long time to be infected and potentially spreading without even knowing it. And on the longer end, (it can take) 14 days, and some have reported even longer than that.”
That’s one reason why having everyone wear a mask is so important, experts said. It’s also further proof of the need for wide availability of testing, which can help detect infections earlier and allow people to isolate before they spread the disease.
5. Some drugs show promise in helping sick people.
Strides are being made in treatment, even if there still is no cure-all.
Remdesivir, an intravenous antiviral drug, has been found to reduce recovery times. The Food and Drug Administration recently expanded its early emergency approval of the drug to treat any hospitalized COVID-19 patient. But the drug is expensive and in limited supply.
Steroids, which are widely available and inexpensive, are also being used to treat patients. Steroids don’t fight SARS-CoV-2, but it’s believed they can help prevent an overreaction of the immune system to the virus that proves fatal in some patients.
The World Health Organization recently called for steroids to be standard treatment for people with “severe and critical” COVID-19. That came after a clinical study concluded that the treatment reduced deaths.
Other potentially promising treatments are being studied. Plasma, which recently received FDA emergency use authorization but has its detractors, is taken from recovered patients with antibodies in their systems and given to sick people.
Monoclonal antibodies created in a laboratory have been used to treat other diseases, like Ebola and cancer. They are now being tested in the fight against COVID-19, with Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, calling it a “promising form of therapy.”
6. Helpful new treatment protocols are emerging.
Khare, who also practices emergency medicine, said his work treating COVID-19 patients has changed significantly.
“It used to be that we would intubate these patients early,” Khare said, referring to the process of putting someone on a ventilator to help them breathe. “And then we found out it’s very difficult to get them off of the ventilator. In fact, it increases mortality.”
So for people with COVID-19, he said, doctors are tolerating lower blood oxygen levels that would normally mean using a ventilator.
Khare added that doctors also have been placing many patients in a prone position, instead of on their backs, to improve breathing.
But, in a sign of how the science keeps evolving, there is concern that patients placed face down could suffer nerve damage.
Landon mentioned that doctors initially were reluctant to use what are known as high-flow nasal cannulas to deliver oxygen for fear that the greater flow of oxygen would help spread the disease. “But it became very clear that patients did a lot better when they got it,” she said, “so we just changed around the way we did our infection control to make it safe to do that.”
7. Even after they “recover,” many COVID-19 patients have lingering health problems.
Another disturbing discovery about COVID-19 is it can leave people with serious ailments — including damage to the kidneys, nervous system, heart and lungs — long after the infection clears their system. Other symptoms that can linger include fatigue and loss of smell and taste.
All of that has given rise to the term “long haulers,” the designation given to people with persistent symptoms.
“We don’t know if those problems are going to be permanent yet,” Landon said. “But the fact that they could be is absolutely in the back of my mind when I say: Please, please, please wear your mask and be socially distant.”
8. Infected children can get very sick.
Early in the pandemic, people were advised that children were far less likely to get sick. That is still borne out by the facts on the ground.
But some children do get very ill. And after the infection is cleared from their bodies, some young children and teenagers develop what’s now called multisystem inflammatory syndrome in children, or MIS-C. It’s a condition that can swell organs and cause them to fail, sometimes to fatal effect.
It also was thought that children were unlikely to spread the disease, but there’s now some evidence that they do.
9. Wastewater testing can help detect outbreaks.
Even as COVID-19 testing becomes more widely available, many cases are still being missed or go undetected for several days while the person is contagious. That interferes with the ability to control outbreaks by identifying and isolating infected people.
Scientists say wastewater testing can help by detecting the presence of the virus even before people develop symptoms. The tests search for fragments of the genetic building blocks of SARS-CoV-2 left in human waste.
“It’s an early warning system,” said Packman, the Northwestern University professor who specializes in surveillance of wastewater and buildings.
When the virus showed up last month in the wastewater from one dorm at the University of Arizona, the school quickly tested all 311 residents, finding two with asymptomatic cases. Those students were quarantined, perhaps preventing a much larger outbreak. Similarly, 287 students were quarantined at Utah State University after the virus was detected in four dorms.
10. Strict stay-at-home orders may not be needed anymore.
When the pandemic started, there was a shortage of protective equipment, a lack of sufficient testing and a dearth of knowledge about the disease. So stay-at-home orders were viewed as the best way to limit the spread of COVID-19.
But six months into the pandemic, with greater knowledge and experience, many scientists now believe masks and social distancing are a workable alternative.
That, Landon said, should dispel the idea that society must choose between a complete shutdown and a wide-open society.
“We now know that’s a false choice — that’s a false dichotomy,” she said. “There certainly are ways to protect people. We are able to protect our health care providers and keep them from getting COVID while taking care of COVID patients. We’re able to protect the public, and we could get on with a lot of things.
“There are a lot of countries,” Landon said, “that have been able to get on with their normal life and not have a thousand people die a day.”
Khare said the message is getting through to many people and it’s brought relief in difficult times.
“For the most part, people feel less anxiety about going outside and visiting with others, meeting at parks,” Khare said. “If you go to Chicago on Saturdays and Sundays, it’s actually a beautiful scene. There are groups of young people that are responsibly social distancing, wearing masks and talking in a circle. Three months ago, that wasn’t going to happen. You were kind of told you shouldn’t do that.
“So, people are learning to live in this new age of COVID-19.”
But he concedes there are still large pockets of resistance to mask-wearing.
“Some of the behaviors and the resistance to putting on masks — I think it’s gotten better, but there’s an unbelievably significant amount of people that just feel like they are not getting treated well because they don’t have the freedom to do what they wish to do,” Khare said. “That’s always to me as a public health person a little bit disturbing. But that continues. That’s America.”