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High Temperature and High Humidity Reduce the Transmission of Covid-19

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Re: High Temperature and High Humidity Reduce the Transmission of Covid-19

#41

Post by _-___________-_ »

I am eagerly awaiting more studies into this subject. Something doesn't feel right about the relative lack of local transmission in e.g. Vietnam (temperatures over 30C at least in the south right now) compared to e.g. Italy (temperatures, what, 15C or lower in the north right now?).

Cambodia's extremely low case count can easily be explained away by them not testing anyone, but Vietnam appears to be quite proactive with tracing and testing, yet still has a relatively low count and minimal transmission.

Re: High Temperature and High Humidity Reduce the Transmission of Covid-19

#42

Post by echelon »

nate_meurer wrote: post #37
tn890 wrote: post #22

Earlier quoted context omitted.

Can someone with a better understanding of molecular biology and virology explain what this means? I don't want to jump to conclusions.

The paper describes how virologists in Wuhan engineered a "SARS-like" virus -- previously limited only to bats -- specifically to make it infective in humans via the ACE2 receptor. That's the same receptor used by the SARS-CoV-2 bug we're fighting now. Note that the paper was submitted 12 years ago. They've had a lot of time to work out the kinks, if they were so inclined. EDIT: I want to repeat what I've said in oth…

Why on earth would they do this? What sort of application does this have or serve?

If it's a bioweapon, why was it published?

Is there any concrete genetic or documented evidence to show COVID-19 is engineered? This is a big claim and has severe ramifications for China, if true.

Re: High Temperature and High Humidity Reduce the Transmission of Covid-19

#43

Post by _-___________-_ »

Animats wrote: post #24

But not by enough. This epidemic has a growth rate (R) of at least 2. The article claims "One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively." The March to July difference for New York City is only 19C. San Francisco, 9C. For both cities, humidity is relatively uniform year round. Even assuming this result is meaningful, it still leaves…

There are plenty of places that are hotter all year round, or have a larger temperature+humidity difference between seasons. Or was your comment only intended to address large US cities?

Re: High Temperature and High Humidity Reduce the Transmission of Covid-19

#44

Post by kijin »

Animats wrote: post #24

But not by enough. This epidemic has a growth rate (R) of at least 2. The article claims "One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively." The March to July difference for New York City is only 19C. San Francisco, 9C. For both cities, humidity is relatively uniform year round. Even assuming this result is meaningful, it still leaves…

In many parts of China, it will be 30C hotter and 50%p more humid in the summer than it is now. The combination might reduce R to virtually nothing.

In Japan, this could mean that it was the right decision to schedule the Olympics in the middle of summer after all.

Re: High Temperature and High Humidity Reduce the Transmission of Covid-19

#45

Post by tomerico »

svscam wrote: post #11

Here's a likely related paper from 2007: https://jvi.asm.org/content/82/4/1899 In this study, a human immunodeficiency virus (HIV)-based pseudovirus system was employed to address these issues. Our results indicated that the SL-CoV S protein is unable to use ACE2 proteins of different species for cell entry and that SARS-CoV S protein also failed to bind the ACE2 molecule of the horseshoe bat, Rhinolophus pearsonii.…

Wow. Quite an eerie find. Where did you come across it?

Re: High Temperature and High Humidity Reduce the Transmission of Covid-19

#46

Post by virtualwhys »

_-___________-_ wrote: post #41

I am eagerly awaiting more studies into this subject. Something doesn't feel right about the relative lack of local transmission in e.g. Vietnam (temperatures over 30C at least in the south right now) compared to e.g. Italy (temperatures, what, 15C or lower in the north right now?). Cambodia's extremely low case count can easily be explained away by them not testing anyone, but Vietnam appears to be quite proactive w…

What doesn't feel right?

The abstract states that high temperature and high humidity reduce transmission rates relative to colder climates, which corresponds with the high transmission rates during the northern hemisphere winter and early spring.

And yes, lack of testing has resulted in some eyebrow raising numbers.

Up in Da Nang now, both locals and foreigners are aware and taking it seriously -- scary times.

Re: High Temperature and High Humidity Reduce the Transmission of Covid-19

#47

Post by snapetom »

Animats wrote: post #24

But not by enough. This epidemic has a growth rate (R) of at least 2. The article claims "One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively." The March to July difference for New York City is only 19C. San Francisco, 9C. For both cities, humidity is relatively uniform year round. Even assuming this result is meaningful, it still leaves…

The study uses relative humidity, which is affected by the dew point. While straight humidity is often consistent at least in the US, relative humidity fluctuates wildly. Relative humidity is what gives the muginess feel. Most of the US except the Rockies and most of the West Coast have way higher relative humidity in the summer months. NYC can get especially bad (or good in this case). In the South, that increase has already started.

Admittedly, it's not a huge affect, but taking your NYC example, the temperature alone will decrease the R0 by at least .5. I'll take that.

Re: High Temperature and High Humidity Reduce the Transmission of Covid-19

#48

Post by tomerico »

Animats wrote: post #24

But not by enough. This epidemic has a growth rate (R) of at least 2. The article claims "One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively." The March to July difference for New York City is only 19C. San Francisco, 9C. For both cities, humidity is relatively uniform year round. Even assuming this result is meaningful, it still leaves…

It's important to understand the limitations of the paper. the paper simply plotted a set of regions where the outbreak happened, and analyzed the growth rate in these regions vs the average climate in that region. Notably, it did not include areas where there was no growth (which coincidentally, are almost universally hot or tropical regions). If those were included, you'd have seen a much larger effect.

With that said, even with just including areas with the epidemic - it found a statistically significant effect. Just, as you note - not a significant effect (which doesn't mean that a significant effect might not exist)

Re: High Temperature and High Humidity Reduce the Transmission of Covid-19

#50

Post by thysultan »

Animats wrote: post #24

But not by enough. This epidemic has a growth rate (R) of at least 2. The article claims "One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively." The March to July difference for New York City is only 19C. San Francisco, 9C. For both cities, humidity is relatively uniform year round. Even assuming this result is meaningful, it still leaves…

I think this serves to better explain the low case totals out of africa, but that might change in the near future.
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