This partially explains how quickly this virus spreads, and why such incredible measures are required to stop the spread.
This won't help in determining how long to quarantine packages unless someone finds out what the typical viral transfer is e.g. when sneezing or when handling a package with contaminated hands - and how many/few viral particles "ingested" may cause an infection.
I don't think one can simply conclude at all that "viruses will survive X days on cardboard/steel/plastic" because viral particles go through an exponential decay in the environment -- so more particles == more time to inactivate all the viruses, and the reverse.
As far as I understand it, there's no predetermined "viable lifetime" (a sort of biologic clock and death) of a virus, the environment will just eventually destroy it and that point seems essentially random for an individual viral particle with different probability distributions on different surfaces.
So if you start with a viral load that is higher, you will be able to detect viable viruses longer.
So these numbers, e.g. detectable for 3 hours in aerosol don't mean anything unless the average human sneeze excretes as many viral particles as a "3-jet Collison nebulizer". If we excrete more than more viral particles remain viable longer and the detection threshold is reached later. If less, than those 3 hours don't apply.
The study just says they were able to detect live viruses after that amount of time, not that they would definitely infect you. It's likely that the odds of infection are very low before that 3 hour mark.
Unless I'm misreading the study.
Well, that one's true, but the flip side of that, which nobody here has wanted to address so far, is that to the extent the transmissibility is calculated based on corresponding data, that estimate is going to be deficient instead, because it's failing to include some of the contagion that resulted in cases that went undetected. Hopefully the people making the estimates know better than that because of other data sources, but the main one I can think of (maybe aside of South Korea's broad biochemical testing, which may be a relatively unbiased sample according to my perception?) is contact tracing of confirmed cases. And I think it's downright likely that at least our contact tracers would miss fomite transmission and persistent aerosol transmission until now, because the party line touted here, at least officially, is "you get the disease though close contact over a long time with someone who is sick" lately expanded to include "or if somebody coughs or sneezes at you" (emphasis mine).
The other thing I can think of to somewhat reconcile the observations is even if the virus has a high durability in the environment, the total transmission process would be contingent on other factors too, one of which is the dose needed to get an infection going.
I have a life science background, but not specific expertise in this area. Would appreciate if someone has good clarifications to share about how accurate the transmissibility estimates are likely to be and why.
Also if the R0 value is much higher than the current estimate it’s good because it would also means it has a much lower mortality rate and overall much less lower severe infection rate than what we currently can estimate.
R0 values are very hard to calculate for novel viruses you usually only can figure it out after multiple outbreaks where you can account and control for environmental and societal conditions.
Based on the numbers South Korea has put out for numbers of infected vs tested and the extensive contact tracing they've done, it doesn't seem that this virus quite reaches that level of infectiousness. I think there's more to the story, like HCoV-19 may have a half life long enough for experiments to detect on surfaces and in an aerosol, but short enough that it doesn't present enough of a viral load to infect anyone relatively quickly.
Since we're learning that the fatality rate is much lower than SARS, as was feared early on, and that it's much more mild of an illness -- and also that it's highly contagious and already widespread -- it strikes me that the opposite is true.
We should do everything we can to protect the elderly and ill, but a disease that is so mild that 85% of people over 80 still survive it, it doesn't strike me as something worth tanking the global economy over. If you're middle-aged or younger and you drive to work, travel internationally, drink alcohol, etc., you've taken similar risks as COVID-19 poses to you.
This is incredibly unpopular on HN, and I'm ok with that. Holing everyone up in their apartments for the next year would put almost everyone reading this out of a job, many without housing, and without healthcare. This is a "keep calm, wash your hands, and carry on" moment, and we're failing.
Here's a distribution of Italian deaths: https://external-preview.redd.it/nOYqCT3-3vzX6aPnaHk3Jb6LSvS...
Note that over half the deaths are over the average age of life expectancy of an Italian.
edit: And once your health system collapses anyone who needs hospitalization for any reason is in trouble.
Even without high morbidity rates, a survival rate of 85% without treatment is still horrific in scenarios where local healthcare systems become overwhelmed. Reading accounts of just that happening in Italy is chilling.
Sorry, I'd rather take a 2 months economy hit, than a long term burn.... which will cause a longer term economic problem as well.
If you decide to get it now, you probably have a job. If you decide to get it later, you quite possibly don't.
People really need to stop spreading misinformation.
My amateur understanding is that accelerated contagion of COVID-19 will destroy your country's health infrastructure, and then many people who don't have COVID-19 will start dying too because healthcare can't reach them. That's why delaying infection is so valuable. It's not just about the direct symptoms that most people get.
You're wrong, though. Regardless of how dismissive you want to be about people getting the virus, they are going to have symptoms that make them seek treatment. the system cannot accommodate large numbers of people seeking treatment.
No one is going to "keep calm" when they feel severely ill, they're going to rightly seek help from doctors. The crisis is when lots of people seek that help at once. We are trying to prevent that and it's worth it!
If the US economy takes a shit, it's going to be because the government is offering no financial help whatsoever to the people who are going to be destitute when they miss work.