Guys, rather than arguing over whose facts are more correct (only a good historical accounting will be able to decide), why don’t we keep focus on who is providing good actionable information.
Clearly, information and models are changing almost daily (mostly for the better thankfully) and we should focus on what we can do to stay positive and healthy.
https://www.google.com/amp/s/mediabiasfactcheck.com/cnn/%3Famp
Cool website they even rated cnn and msnbc!
It’s a good thing none of these are where I educate myself. News channels, for the most part, are for those unable to critically think for themselves.
Guys, if we are unable to be civil, I will be forced to move much of this discussion to the politics section, and as one of the mods, I am getting tired of moving stuff there. Can we please just be civil.
Exactly.
I would like to find info on what they are really counting as cases. Those admitted to hospital for treatment ? Or those who call their doctor, doctor says to get tested (based on symptoms), and then blood test or throat swab comes back positive, and most told to just stay isolated?
Do the treat at home get counted?
I also see mixed messages about being passed on when infected person coughs or sneezes, not through normal breathing. Others say can be passed from just normal breath carrying virus.
And when in lines, 6 feet apart, then lines moves along, aren’t you repeatedly walking into what person in front of you just exhaled? (I started wearing a scarf/mask) in this scenario.).
@MM2 I think the reality is it’s confusing because even the experts are sort of winging it.
I think anyone who tests positive is counted as positive right now. But plenty of people in NYC and California I know are being told “act as if you have it – I don’t doubt you have it, but I can’t get you tested.” Those people are not being counted. Right now, the directive in California is only to test those who are healthcare workers or who are hospitalized – even close contacts of a confirmed case who are symptomatic are not getting tested because of the backlog. So our undercount right now is likely pretty severe in California. New York has done way more testing, so it has the best idea of its outbreak – but it’s also so much more prevalent there that there are still tons of people who are being told to self-isolate as if they have COVID-19, without the benefit of a positive test result. Then, too, about 30% of these tests are false negatives, so if you have symptoms and, say, your relative tests positive, you should assume you have it even if you test negative.
We have the rough outlines of how the disease is transmitted, but we don’t know how important each mode is for transmission. Which reveals something about how little we understood even common respiratory viruses like the flu. For instance, we know contact transmission *can occur – but how dominant is it as a mode of transmission? Is transmission through inhalation through the nose or via the mouth more dominant? We know that respiratory droplets (i.e. fairly large gobs of mucus that fly out when you cough or sneeze) can transmit the virus, but how important are aerosol droplets (smaller ones that stay suspended in air rather than falling to the ground)? We’ve studied influenza for years and we still don’t really know…
Newer research shows that respiratory droplets are one way of things transmitting, but a case of a choir in Skagit, Washington where at least 45 people were infected, suggests that aerosols may play a role as well. We think that talking or shouting or singing (or sneezing) would propel things further and more would come out of your mouth. But in theory, you are emitting some small viral particles even when breathing. Because we don’t know how many virus particles it takes to become infected, and we don’t know how each case became infected, we can’t say how common any given mode of transmission is.
What experts have told our reporters: 6 feet is probably fine when you’re on the street, but if you’re in an enclosed space with poor ventilation, it may not be enough. 6 feet from someone in a conversation for 2 hours is probably not safe. 6 feet as you walk by them quickly is plenty.
There is also evidence of contact transmission and presymptomatic transmission: 1 in Singapore, where a couple from China sat in one seat at a church, and then at a later service someone who sat in the same seat contracted COVID-19 (case report doesn’t say how far in time these two events were separated, but I am guessing maybe an hour?)
One case where a person was in a singing class with someone, then later had symptoms, and transmitted it before symptoms appeared:
BUT, the one thing I find reassuring is that when people do the contact tracing (which for the most part we’re not doing here anymore), they find that by far the biggest risk is having “sustained” close contact with a person, which basically means being in their presence, talking to them, for like 15 to 30 minutes. Each of these cases of transmission could have occurred via sneezes, or breathing, or talking, or touching something contaminated – we don’t know. But that does give us some confidence to say that certain things, like briefly walking past a person on the street briefly, is lower risk.
Personally, I’m still wearing a homemade mask, mainly because I could be infected and not know it, and a new study suggests that masks do contain droplets and aerosols well, even if they maybe don’t do a great job of blocking them from the outside.
Thank you for taking the time to make that detailed post. You make a number of good points including that what we know is changing so quickly.
The choir in Skagit, WA is an interesting case. It seems reasonable to think that singing (particularly by trained singers that know how to REALLY sing) is probably a lot closer to sneezing and coughing in terms of emitted droplets.
There was a faculty member at MIT who has studied this and claims that sneezes and coughs can move particles as far as 25 feet.
I am also wearing a homemade mask when I pickup takeout food or other cases when I am likely to be comparatively close to anyone. When I walk the dog, I can cross the low-traffic street or walk off a paved trail so that I don’t encounter anyone at a range of less than 30 feet. In that case, I am not wearing my homemade mask I know that not everyone has that luxury when they walk.
Stay safe out there.
John
So true - we do not know, and understandably so - it is very difficult to tell how transmission may occur and how likely each mode may be. Thanks for the Singapore reference. This recent NPR article provides a good summary of our current knowledge and various expert opinions.
Thanks, your response and the articles you linked is just what I was looking for.
Nor do we know, yet, the relationship between “dose” of exposure and infectivity, let alone severity of disease/risk of fatality.
Just read a probing piece in the (sorry, left-leaning!) New Yorker by biologist/oncologist Siddhartha Mukherjee that explores this and other questions. We will have time afterwards to more carefully examine the data, spotty as it is right now, and get a clearer picture of how this virus acts and moves.
https://www.newyorker.com/magazine/2020/04/06/how-does-the-coronavirus-behave-inside-a-patient
I rarely post from my site, but I think this story was very interesting – about the possibility of spread via speech.