I have been deeply concerned about the level of misinformation being provided to the public on coronavirus and the degree to which scientific papers are misinterpreted by the lay media, but I had an experience yesterday that raised my worries to a whole new level. This experience suggests that the flood of information on coronavirus, much of it preliminary or partially digested, coupled with the ease and speed with which misinformation can be widely disseminated make all of us, even the most skeptical and highly trained, susceptible to viral misinformation. I have tried to dig into this as a case-study in information epidemiology. How did this disease of misinformation get started and how did it spread?

This particular story came to my attention, when a friend shared my blog with a group of senior scientists. They both liked the blog but took exception to my assertion that Covid19 is not what epidemiologists would consider an airborne disease. My goal is not to shame anyone, because I think these mistakes are easy to make, so I will refer to them as Scientist A and Scientist B and paraphrase their responses. 

Scientist A:

A recent colloquium at UCSF med school concluded that it’s spread primarily by breathing infected people’s exhaled air, even if they’re not coughing.  

Scientist B:

You’re right.  The smallest droplets from coughing, sneezing, or breathing stay in the air three to four hours.  If someone with COVID19 coughs or sneezes in the grocery aisle and you walk down it an hour later, you could become infected.  

When I first saw this, I was mortified. The statement, “. .it’s spread primarily by breathing infected people’s exhaled air, even if they’re not coughing”, was contrary to everything I had read. But it seemed experts at a top medical school were suggesting just the opposite. Was there something I had missed? I thought I had researched this carefully, but had I just gotten it wrong? I began thinking about how I would explain this horrible gaff and figuring it might be time to shut down my blog if my information was so completely wrong. 

There are two different sources of misinformation here. Scientist B is referring to a recent paper, which has been widely misreported in the press. I will get to it in a later post, but suffice it to say he’s not quite correct about viruses hanging out in grocery aisles. So, I wasn’t worried about the second comment, but the first had me worried. If this could be spread by people breathing, then I was passing out bad information and I was dangerous.

So I went back to my friend to ask if she knew any more about the colloquium. She pointed me toward the UCSF website, where there was a link to video of a webinar that she presumed was the source. When I tried to watch it, I discovered it was only for staff, students and affiliates of UCSF. I am trying to get access to that video, but if I couldn’t watch, neither could either of these scientists. What had he seen?

It turns out there is a set of notes taken by a Bay Area endocrinologist that has been widely circulated on this topic. My friend shared that document with me. It consists of a list of 12 takeaways from an “infectious disease conference” at UCSF. At first glance, all of the information looked consistent with what I was hearing. Then, item #5 jumped out at me.


5. Findings confirm that COVID-19 is spread simply through breathing, even without coughing. It seems unlikely that contact with contaminated surfaces is a primary means of spread: “Don’t forget about hand washing, but if you don’t want to get infected, you can’t be in crowds.” …….

I had never seen any research suggesting this disease is spread “simply through breathing” with no one coughing. If there was evidence of such a thing, I needed to track it down. Then I noticed that there was a Covid-19 FAQ list on the UCSF website. I clicked on it and one of the first questions listed was, “How is it spread?” Their answer:

The virus that causes COVID-19 is spreading from person to person. Someone who is actively sick with COVID-19 can spread the illness to others. The principle mode of transmission is still thought to occur mainly via respiratory droplets that travel up to six feet in the air after an infected person coughs or sneezes. This transmission is similar to how influenza and other respiratory pathogens spread. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs.

Close contact with an infectious person, such as shaking hands, or touching a doorknob, tabletop or other surfaces touched by an infectious person, and then touching your nose, eyes, or mouth can also transmit the virus. It is not yet known how long the new coronavirus can survive on surfaces, but based on data from other coronaviruses, such as SARS, it may be for up to two days at room temperatures.

This agrees with everything I have been telling people and directly contradicts the “notes” from the meeting. THERE IS NO MENTION OF IT BEING SPREAD BY BREATHING WITHOUT ANYONE COUGHING.

That is where the mystery of misinformation begins. Did someone on the webinar misspeak? If so, how did they get it wrong. If not, how did the author of the notes get it wrong? And how did it circulate so widely? Today, I will begin to dig into this. By tomorrow I hope to have some answers.