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.