A son mentioned this for the first time a couple of days ago, and it struck me as odd that we haven't heard more about it. It matters in a great many other contagious diseases, so I assume it matters with C19 as well. It is one explanation why masks and gloves work with contagious diseases in general.
Is it not being mentioned because public health officials fear it would cause people to be less vigilant?
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At a guess, they're not talking about it because they haven't a clue.
I don't mean to disparage. Solid information, as opposed to educated guesses, takes time (and money).
I think James is right. Ben Rhodes described the typical journalist as a 26 year old who knows nothing (in part because they got their BA in journalism rather than, say, history or pre-med). They don't know what they don't know.
In fact almost nothing being written by journalists on this subject is worth reading. Even when they are interviewing a knowledgeable figure, that person is giving them a summary he thinks the journalist will understand; and the journalist is then repeating back whichever part they did in fact understand, as well as everything they misunderstood.
I suppose it can cut both ways. It might encourage incautious people to risk more exposure in the mistaken belief they only face a slight risk but could encourage people who must risk exposure, like delivery drivers or clerks, to do things to minimize it. I would lean toward more information being better since the incautious people are likely to take those risks regardless of what you tell them. Nobody can heed a warning that's not given.
To Grim's point, even people that could be held out as experts by journalists might not give good information. Powerline's Scott Johnson posted a letter from an MD reader working Boston as a counterpoint to some of the C19 analysis done by the members of that group. I'm sure he's very sincere in his opinions and observations but it was as full of speculation as anything I've read.
My (very vague and very recent) understanding of viral load is that it is a pretty good proxy for what shape you are currently in, but that a small load of virus can quickly become a large load of virus with the forced participation of your own cells.
So while avoidance of people with a large load (and thus lots of "shedding") is a good thing, even exposure to droplets from someone with a small load that is not going to even bring them any symptoms could be enough (with replication within ones self) to cause you great harm.
I suspect, however, that the more you get in initial "dose" the harder it is for your immune system to get ahead of it, and hence the "cytokine storm" that we've seen causing such damage to people.
There's two different things involved here: the amount of virus that a sick person is shedding (and where they're shedding it, such as nasal fluid, droplets, aerosols, feces, etc.); and the amount of virus that you are exposed to initially.
For the first: how much you are shedding, and where, tells how infectious you are. Initial reports are that people sick with COVID shed very large amounts of virus, both into the respiratory mucus (which can then be aerosolized by vigorous breathing, coughing, pulmonary treatments, etc.) and into feces (which is spread by touching with unwashed hands, and by toilets that dropletize/aerosolize material when flushing vigorously). As your body defeats the virus, this kind of "viral load" (the load in your body) drops gradually. Some reports say dosing with hydroxychloroquine and/or antivirals also drops amount of virus dramatically and quickly, which would make you much less infectious right away (hence, safer for medical people and family members to be around).
For the second, and more interesting to me, is the "viral load" that initiates an infection. Here, this "viral load" is the "dose" you get initially. There is a lot of evidence that lower initial doses lead to much milder illness-- this was the reason why "variolation" (deliberate infection with smallpox) worked: they used scabs from a patient who was almost well, then left them for a long period of time in sunlight (i.e., a very low initial viral loading), to inoculate another person deliberately, which rarely resulted in serious illness but still conferred future immunity. This was definitely true for SARS-- a higher initial dose, and repeated exposures, were highly correlated to severe outcomes (e.g. at the Amoy Gardens housing complex in Hong Kong).
So, hypothetically, you get a dose of 10-1000 viral particles once, your body clears it in a few days with no noticeable symptoms, and you get partial or total immunity afterward. If you get 10,000-100,000 particles once, you get a nasty, flu-like illness for 7-10 days, then get over it. But if you get 1,000,000+ particles, or 100,000+ a day, for 5 days straight, because an asymptomatic guy at the gym is panting them out on you for an hour... then you end up in the ICU with a tube down your throat (if they have a bed for you in the ICU, and a tube for you, that is). It might also matter how you receive the virus: in an aerosol that penetrates deep in your lungs, in droplets that stop in your sinuses, touching your eyes with dirty hands, or in food that somebody with dirty hands handled.
But nobody knows what those numbers might be, or even for sure if this is true.
I wonder. I had the impression that the body had lots of generic defense, which, when you introduce a new pathogen, have some probability of disposing of it before it gets a foothold. Once the system recognizes it, it adapts to try to produce more of the anti-bodies or whatever is appropriate. If it gets too late a start, you suffer and maybe die.
If that model is more or less accurate, then it would be possible, with a large enough dose of infectious agents, to overwhelm a system that was nominally immune. Which would have implications for front-line workers here.
Laura, thank you. Very clear information
The wife and I went shopping yesterday, and we put on masks before going in. First, my glasses fogged up, from my exhalation. At the checkout, my nose started running, and my wife's nose was a little bit later. I blew my nose when we got out (I always carry 4 hankies.)
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