Sources:
- Nature study, 20th Nov https://www.nature.com/articles/s41467-020-19802-w
- Maria Van Kerkhove, head of the WHO Emerging Diseases and Zoonosis unit https://www.youtube.com/watch?v=NQTBlbx1Xjs
- Fauci in 2018 https://www.youtube.com/watch?v=vrAvjU2LBkg&feature=emb_titl...
I, asymptotic young person with nCoV 2, am spreading it today. The “yet” part is completely irrelevant to this point in time.
In colloquial usage, asymptomatic encompasses presymptomatic. In technical usage, they are different.
If you develop symptoms, then when you were a carrier before then, you were presymptomatic, rather than asymptomatic.
Of course, whether you go on to develop symptoms or not, its still highly pertinent information if asymptomatic spread is not a major driver of infection. As long as you self isolate upon symptom onset that should be enough. It does call into question whether isolating the apparently healthy is an evidence-based public health policy intervention though.
We used to think true asymptomatic infections (never develop any symptoms but test positive) were ~50% of those infected. More recent research puts it at closer to ~20%. Again, some reporting bungled this by reporting studies from controlled populations (like a cruise ship) before they knew if cases were asymptomatic or pre-symptomatic, causing people to quote the number as the former, when it was really a mix.
COVID spreads like wildfire by pre-symptomatic people. There are mountains of evidence to support this. Spread by asymptomatic people is speculation.
> Of course, whether you go on to develop symptoms or not, its still highly pertinent information if asymptomatic spread is not a major driver of infection.
Not sure, but I think you may be using the word "asymptomatic" to denote pre-symptomatic in this sentence.
> As long as you self isolate upon symptom onset that should be enough.
It is not enough.
There is absolutely a difference between 'yet to have' and 'never will have' but I think it is potentially confusing to attempt to delineate between asymptomatic and "pre-symptomatic".
The main concern with messaging that causes confusion in this regard is that a superficial reading of "asymptomatic doesn't spread virus" would imply that if you aren't symptomatic, you aren't a danger.
And the viral load is high two days before the symptoms onset. If you want a proper RCT about it, good luck approving it in an ethics committee.
Asymptomatic has a strict definition. You get the virus and nothing happens to you. This is what the WHO and Fauci are referring to.
But most "asymptomatic" cases aren't. They are either paucisymptomatic (you have mild symptoms - maybe too mild to notice) or pre-symptomatic.
Obviously if people were only contagious if showing symptoms, the pandemic wouldn't be.
> Obviously if people were only contagious if showing symptoms, the pandemic wouldn't be.
I don't think that is obviously the case at all. It would have to be proved. The dominant vectors of contagion are not yet well understood - we could be dealing with very highly infectious airborne virus, that is capable of spreading widely from a relatively small number of symptomatic and pre-symptomatic super spreaders.
The fact remains that current public health interventions orientate around isolating individuals whether they are symptomatic, asymptomatic or paucisymptomatic. Moreover, to greater and lesser degrees we also isolate the healthy, assuming them to be asymptomatic in an abundance of caution. Considering the negative non-covid related knock on effects of these policies its at least worth investigating isn't it?
The calculated R0 does not support this theory. Measles works this way. R0 for Measles is > 10
> that current public health interventions orientate around isolating individuals whether they are symptomatic, asymptomatic or paucisymptomatic
Everywhere, the restrictions are higher if you were tested and/or is suspected of having Covid. Of course a lot of people DNGAF about the restrictions, which is part of the problem.
Again, if your theory that people showing no symptoms do not transmit the disease then it should be super easy to go around and start finding people spreading it. But it isn.t
People will say to themselves well, it's just a cough right? Just a cough. I can't have COVID-19 that's something other people get, those people are sick but I'm healthy, this is just a cough. And that allows the virus to spread.
Or you notice them but because they also match symptoms of colds and allergies, and you’ve been getting them on and off for months, you assume they aren’t COVID.
I don’t think there has been an interval longer than a week since February during which I didn’t have at least a couple symptoms that could have been COVID.
I’ve not had the taste/smell loss, and all my contact with other people has been masked and brief, and I’m in an area where spread has been low, so I’ve probably not had it, but I wish we had widespread cheap testing so I could know.
Exactly. I have occasionally runny nose combined with sporadic sneezes and coughs pretty much every winter. If someone like my had so "mild" COVID symptoms they would consider themselves asymptomatic (paucisymptomatic?), and rightfully so. (My actual COVID symptoms were not as mild, but not very serious either.)
It's remarkable the number of people anecdotally reporting similar symptoms - often out of character for otherwise robustly healthy individuals. I'm guessing some sort of psychosomatic response to the year's stresses.
I have been having the same, but the main reason why I notice it now is that every time I have any symptom, even the mildest of them, I take notice and consider the possibility of Covid, whereas in past years I would forget about them if even notice at all.
For context, I'm a fairly healthy individual who hasn't seen a GP or other medical doctor in at least a couple years, probably longer. Last time I've been to one was because of exercise-related injuries.
This is hypochondria isn't it? A pathology in its own right, no doubt caused by current events.
It's not hypochondria, it's simple awareness.
That being said it seems the most specific symptom is loss of smell/taste so unless you have that it's probably something else (disclaimer: not a doctor and this is not medical advice)
https://www.theglobeandmail.com/canada/toronto/article-stude...
Still not obvious one way or the other about whether these students and staff are spreading it amongst themselves or if they all got it from other symptomatic cases in the community and independently brought it to school with them. But either way, it's sobering how much of it is going undetected.