Nicole Lawson spent the beginning of the pandemic incredibly worried about her daughter, who has asthma. Five-year-old Scarlett’s asthma attacks were already landing her in the ER or urgent care every few months. Now a scary new virus was spreading.

Respiratory viruses are known triggers of asthma attacks and doctors also feared at the time that asthma itself could lead to more severe coronavirus infections. So, Lawson’s family in Ohio hunkered down quickly and masked up often to keep Scarlett healthy.

The ensuing months, to everyone’s surprise, turned into “this beautiful year,” Lawson told me. Scarlett hasn’t had a single asthma attack. Not a single visit to the ER. Nothing. She’s breathing so much better, and all it took was a global pandemic that completely upended normal life.

All around the country, doctors have spent the pandemic wondering why their patients with asthma were suddenly doing so well. Asthma attacks have plummeted. Paediatric ICUs have sat strangely empty. “We braced ourselves for significant problems for the millions of people living with asthma,” says David Stukus, Scarlett’s doctor at Nationwide Children’s Hospital.

“It was the complete opposite. It’s amazing.” Fears about people with asthma getting more severe Covid-19 infections haven’t been borne out either. Studies in other countries, including England, Scotland and South Korea, also found big drops in hospital and doctor’s-office visits for asthma attacks.

The massive global experiment that is the pandemic is now leading doctors to rethink some long-held assumptions about the disease. Asthma is a chronic condition that occasionally flares up, leading to 3,500 deaths and 1.6 million emergency-room visits a year in the United States.

These acute attacks can be triggered by a number of environmental factors: viruses, pollen, mould, dust mites, rodents, cockroaches, pet dander, smoke, air pollution, etc. Doctors have often scrutinised allergens that patients can control at home such as pests and second-hand smoke. But patients have stayed at home for a year and suffered dramatically fewer asthma attacks, suggesting bigger roles for other triggers, especially routine cold and flu viruses, which nearly vanished this year with social distancing and masks.

With life in the US snapping back to normal, asthma doctors and patients are facing another new reality. Masks are going away; schools will be reopening in the fall. The pandemic unexpectedly reduced asthma attacks, and now doctors and patients have to navigate between what they know is possible in extraordinary conditions and what is practical in more ordinary ones.

The most compelling evidence that asthma attacks truly did go down during the pandemic exists because of a stroke of good luck.

Back in 2018, Elliot Israel, a pulmonologist at Brigham and Women’s Hospital, in Boston, began asking Black and Hispanic or Latino adults with asthma to track their attacks at home for a study called PREPARE.

These groups have disproportionate rates of severe asthma, compared with white patients.

Israel intended to compare two different ways of using long-term asthma medication, such as inhaled steroids. His team enrolled its last participant – patient No.1,201in – March 2020. The Covid-19 shutdowns began a week later.

“We were very lucky,” Israel said. Because of the study’s timing, his team had plenty of data from before the pandemic. And because the participants were filling out monthly questionnaires from home, the shutdowns did not affect the data collection.

Meanwhile, Israel, like his colleagues across the country, was noticing an eerie lack of non-coronavirus patients. Hospital visits for heart attacks and strokes were also dropping during the pandemic. Were asthma patients just avoiding the hospital because they were afraid of catching the virus?

“That was the initial thought: What if these people are suffering at home?” says Justin Salciccioli, a pulmonologist at Brigham and Women’s Hospital and a co-author with Israel on the resulting paper about asthma attacks during the pandemic.

The answer became clear as the monthly questionnaires started rolling in. The number of attacks the participants suffered at home really was dropping. It fell by 40 per cent after the onset of the pandemic. “We know that this isn’t reluctance to go to the emergency room,” Israel said. “This is a true, real decrease.”

In that case, why? Israel and his team didn’t see a clear pattern connected to changes in air pollution. People who normally worked outside the home, however, had bigger decreases in asthma attacks than those who worked at home (65 per cent compared with 23 per cent), perhaps because they were no longer being exposed to viruses and irritants at work.

And people whose type of asthma is driven by environmental triggers also saw bigger improvements than those whose asthma is driven more by underlying inflammation. All of this suggests that people really were able to avoid triggers during the pandemic.

Ordinary respiratory viruses may play a bigger role in asthma attacks than previously thought, Israel said. People with asthma, like everyone else who masked up and practised social distancing, were this year exposed to many fewer viruses known to trigger flare-ups. Even asymptomatic infections that normally go unnoticed might cause an asthma attack in someone whose airways are especially sensitive. “That extra irritation, that extra inflammation, pushes them over the edge,” Israel said.

Asthma experts I spoke with all agreed that reduced viral exposure likely played a part in the drop, but the pandemic changed so many things at once that other factors are hard to rule out. Staying at home might have made it easier for people to keep up with their regular long-term asthma medication.

They were also no longer exposed to potential triggers at work or school, such as diesel from school buses or chemicals in cleaning products. Asthma can be very individual, with exact triggers varying from person to person. But the overall picture is impossible to ignore: The sweeping changes to our social lives during the pandemic made asthma a lot easier to control.

If viruses indeed play a bigger factor in asthma attacks than initially thought, doctors might have been mistakenly fixating other factors. “We’ve forever talked about the environmental contribution to asthma. There are pollutants and irritants and allergens inside the home,” says Stukus, who is also a member of the Asthma and Allergy Foundation of America’s Medical Scientific Council. If these factors really were so important, though, asthma attacks should have gone up, not down, during the pandemic.

It’s long been routine for doctors to question parents of kids with asthma about dust mites or cockroaches or smoking in the home, says Christopher Carroll, a paediatric-critical-care doctor at Connecticut Children’s Hospital. He’s asked these questions himself. But, he says, “the unstated implication when you’re asking about triggers like that is that those are causes of your child’s asthma.”

This has the effect of blaming patients or parents of patients, when factors outside the home might actually play a bigger role. “We have this paternalistic attitude in medicine,” adds Janine Zee-Cheng, a paediatrician in Indiana. “You’re noncompliant with your medicines. Or you’re not monitoring your kid’s medicines. Or you’re smoking indoors.” It’s “doctor knows best” – but the pandemic has exposed how much doctors did not know.

Rethinking the role of viruses in asthma attacks is a bit more complicated in practice. Covid-19 precautions tamped down every other respiratory virus, but those precautions won’t last forever. Cases of respiratory syncytial virus, one cause of the common cold, have already spiked.

Carroll expects that he will keep wearing a mask in hospitals, but masks are coming off everywhere else. More and more now, wearing one means sticking out. And unfortunately, the health benefits of a face mask have also been overwhelmed by its potency as a political symbol.

This is what worries Lawson, as Scarlett goes off with her friends and begins pre-K in the fall. She can’t keep Scarlett cocooned forever. Her daughter will be exposed to viruses. “I would be lying if I said it didn’t make me anxious,” Lawson said.

Masking up in the winter seems like a no-brainer, but she can already imagine the judgment her family might face. This choice isn’t about politics, though. It’s about Scarlett’s asthma. Lawson remembers the two Thanksgivings in a row when Scarlett got so sick, she had to be hospitalized. It didn’t happen this past Thanksgiving, and she hopes it never happens again.

• The Atlantic report