[kalipsosu]

For flu, each sick person infects 1 person. So Ro is 1. This means no quarantine needed. But for covid-19 estimated Ro is around 2.5. So containing this virus requires quarantine. Also this is a novel virus which means this strain is new and may be unpredictable. Mutations may occur. We even not sure about source of the virus. If it spreads all over the world it could logarithmicly grow in number. Especially for undeveloped counties with weak healthcare infrastructure pose a real threat.

[droithomme]

> for covid-19 estimated Ro is around 2.5

Los Alamos study today suggests R0 is between 4.7 and 6.6:

https://www.medrxiv.org/content/10.1101/2020.02.07.20021154v...

[meatsalesman]

It's looking like the R0 is significantly higher.

https://www.medrxiv.org/content/10.1101/2020.02.07.20021154v...

>The novel coronavirus (2019-nCoV) is a recently emerged human pathogen that has spread widely since January 2020. Initially, the basic reproductive number, R0, was estimated to be 2.2 to 2.7. Here we provide a new estimate of this quantity. We collected extensive individual case reports and estimated key epidemiology parameters, including the incubation period. Integrating these estimates and high-resolution real-time human travel and infection data with mathematical models, we estimated that the number of infected individuals during early epidemic double every 2.4 days, and the R0 value is likely to be between 4.7 and 6.6. We further show that quarantine and contact tracing of symptomatic individuals alone may not be effective and early, strong control measures are needed to stop transmission of the virus.

An upper end of 6.6 changes everything.

[baddox]

I'm not a doctor or a public health expert, but it seems to be that unqualified uncertainty should not be used as justification for any action other than pursuing more information to qualify that uncertainty. Otherwise we would maximally quarantine any illness for which we are at all uncertain of an upper bound on its basic reproduction number or mortality.

[retsibsi]

There are degrees of uncertainty, and ranges of plausible severity, even when we haven't actually nailed these down quantitatively. We already have enough information about COVID-19 to raise it far above the threat level of a random virus. And given how quickly and stealthily it seems to be capable of spreading, to take no action beyond 'pursuing more information' would be almost the same as assuming the best possible resolution of our uncertainty. That's no more rational than the other extreme of assuming the very worst.

[kalipsosu]

I am. The most important factor here is Ro not uncertainty. Maybe I should emphasize it more.

[baddox]

I was replying specifically to when you said "Also this is a novel virus which means this strain is new and may be unpredictable. Mutations may occur." I interpreted that as meaning that because of our lack of knowledge about this strain and the fact that it may mutate, some unspecified amount of additional concern is warranted.