Updated: May 21
New report from CDC suggests that COVID primarily spreads person-to-person through respiratory droplets, and that contaminated surfaces are not a primary mode of infectious spread.
There were a small number of studies/articles that suggested solid surfaces were a primary mode of spread, but now it is believed that respiratory droplets is the primary mode.
Given that many of the super-spread events that have seeded outbreaks and hot spots in this disease have involved crowds of people indoors, breathing shared air, and often involving forceful breathing like intense workouts, singing, or talking loud (or coughing or sneezing obviously). These expel large volumes of virus long distances, and emerging knowledge makes it clear that volume of virus one is exposed to is a key factor in determining whether the viral infection takes root.
This reinforces the notion that primary viral mitigation strategies should include (1) mask wearing in indoor public places, especially when around large groups of people, (2) avoiding large crowds, especially settings where people are yelling or singing, and of course (3) covering coughs and sneezes with one's arms.
This does NOT mean we should not disinfect, wash our hands, or be careful in public places, especially surfaces like doorknobs and elevator buttons and light switches that are often touched, but just that the respiratory spread is considered much more common. This means our primary mitigation efforts should potentially be focused on stopping respiratory spread.
Some steps that previously were considered primary mitigation factors including extreme disinfecting of surfaces, restrictions of gathering together outdoors, and preventing people from going anywhere "non essential" without making exceptions for places where social distancing and mask wearing can mitigate spread.
We are gradually learning more fine details about the virus and its spread, and hopefully this will help construct effective targeted mitigation strategies that can limit viral spread while allowing some modicum of normalcy in people's lives.