Effect of heat and humidity on SARS-COV2

[Guderian]

Many people, myself included, had been hoping that the heat and humidity in Thailand might prevent the virus from spreading. The recent increases in new cases don't support that idea, but there does seem to be some evidence that the virus doesn't thrive in a hot, humid environment as well as it does in a cold, dry one. There was an interesting article in this morning's Daily Mail health section by their acting US health editor. This is largely based on research done in China and it's the most comprehensive review I've seen in the public domain so far. And there's even some good news - the heat and humidity here won't stop the virus in its tracks, but it looks like they might significantly reduce the transmission rate from person to person. That effect, combined with strict social distancing and quarantine where necessary, might be enough to allow us to avoid becoming another Lombardy. Let's hope so, anyway.

 

Here's the article if you missed it:

 

https://www.dailymail.co.uk/health/article-8143727/High-temperatures-humidity-significantly-slow-spread-coronavirus.html

 

High temperatures and humidity can 'significantly' slow the spread of coronavirus, but won't completely stop it, study find

• Previous research has suggested that coronavirus can't survive at 86 degrees  F
• President Trump told Americans that heat would kill the virus and suggested it would subside by April but now says it may cripple the US well into the summer
• Chinese researchers found that for every one degree C increase in temperature or one percent increase in humidity, coronavirus's transmission rate falls 
• But rising temperatures won't be enough to the number of people each infected person passes COVID-19 on to to zero  
• Coronavirus symptoms: what are they and should you see a doctor?

By Natalie Rahhal Acting Us Health Editor

Published: 20:06 GMT, 23 March 2020 | Updated: 22:04 GMT, 23 March 2020

Rising temperatures and humidity levels will likely slow the spread of coronavirus around the globe, a new study suggests - but changing weather can't stop the disease alone. 

As the weather grew warmer and more humid in 100 Chinese cities researchers at Beihang University and Tsinghua University found that the transmission rate of COVID-19 fell. 

'High temperature and high relative humidity significantly reduce the transmission of COVID-1, the study authors wrote. 

President Donald Trump for weeks assured the American public that coronavirus, which has now infected more than 41,000 people in the US would likely fade by April because 'the heat generally speaking kills this kind of virus.' 

 

Although public health experts and the new study suggest that the virus doesn't thrive in warm temperatures, heat and humidity will only reduce the transmission rate - not stop it in its tracks. 

 

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As temperatures rose in 100 Chinese cities, the average number of people who those infected with coronavirus passed it to fell from 2.5 to less than 1.5, Chinese researchers found 

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A similar trend was seen with rising humidity, with transmission rates rarely exceeding three when humidity rose to 100% in the cities they assessed. Each blue dot signifies the average number of transmissions per infected person at a given humidity level, meaning that on days when humidity was 100%, the transmission rate hovered mostly below two per infected person

Since COVID-19 emerged in China in December, the virus has spread like wildfire to more than 350,000 people worldwide amid cold weather. 

In China, the outbreak reached its peak in February with more than 15,000 cases diagnosed in a single day. 

But it's officially spring there now, and with the departure of winter has come a precipitous fall of cases in China. 

Last week, China reported no new cases of coronavirus from local transmission - an encouraging development, if one met by some skepticism. 

It came just before the first day of spring (which was Saturday, March 21), but also followed draconian measures that locked down tens of millions of people in Wuhan and other Chinese cities. 

Parsing out the role in weather in China's seemingly successful fight against COVID-19 from other factors is more difficult than simply looking at case numbers and temperatures. 

In an effort to do just that, the researchers at Beihang and Singhua universities assessed data on more than 100 cities in China where there were 40 or more cases of coronavirus between January 21 and January 23. 

 

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They predict that transmission rates will fall to the rate of one person per every infected individual in areas where humidity and temperatures will rise in tandem during the spring and summer months, such as the Easter half and far West Coast of the US 

 

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Nearly 42,000 Americans have been infected with coronavirus. President Trump has said optimistically that the heat might kill the virus, but it's not expected to remain active in the US through the summer despite warmer temperatures  

They tracked the estimated number of transmissions, temperatures and humidities in those cities prior to January 24, when lockdowns went into place and Lunar New Year celebrations were cancelled. 

Using the R coefficient, a number that measures the average number of people each person with coronavirus infects, the team tracked transmission rates. 

They adjusted these numbers to account for factors that might otherwise influence the transmission rate, like how densely populated or wealthy each city was. 

After doing so, they estimated the average number of people that each person with the virus would pass it on to. 

Experts worldwide have tried to estimate the R0, or spread of the disease.

It seems to hover between 2 and 2.5, meaning that every person infected gives coronavirus to between two and two-and-a-half people. 

But that value falls as temperatures and humidity rise, according to the authors of the Chinese study, published earlier this month. 

'One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively.' 

 

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Warmer weather is unlikely to spare the US health care system from becoming overwhelmed. Pictured: A National Guard member in Florida strips off his PPE at a COVID-19 testing site

 

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The researchers not that new cases per day remained lowest in more tropical, warm environments like Thailand and Malaysia, while transmissions were high in drier Iran and Korea

It's a small impact, but not one to be dismissed, according to the researchers. 

'In the early dates of the outbreaks, countries with relatively lower air temperature and lower humidity (e.g. Korea, Japan and Iran) saw severe outbreaks than warmer and more humid countries (e.g. Singapore, Malaysia and Thailand) do,' the study authors wrote.  

Scientists aren't entirely sure why so many viruses - including the broader coronavirus family to which COVID-19 belongs - fare better in colder temperatures in the environment.

But we do know that the human immune system is depressed during the winter. Colder, dryer air dries up the mucous in our noses that act as a first line of defense, and respiratory viruses typically enter through the nasal passageway. 

Certain immune cells, called phagocytes, also seem to be less active in the body at colder temperatures, meaning they're less likely to spot and kill viruses.   

By the Chinese researchers' equation, if the temperature in the US increases by 15 degrees C, or 27 degrees F, an infected person would spread coronavirus to about 0.6 fewer people. 

Coupled with social distancing, this could go a long way to reduce the virus's spread, but it's not a full stop, as some studies citing that the virus can't survive at 86 degrees F might suggest.    

[sikishrory]

someone shared a video to me yesterday saying it lives in your sinuses in the beginning and you can kill it by exposure of 15 mins a certain number of times to 56° Celcius heat. 

suggestions were sauna, dessert (<deleted> idiots) or misting your face with water while shooting a hairdryer up your nose. your hand covering the inlet a bit so it runs hotter.

now. i don't believe everything i read on Facebook so i googled around.

there is truth to it but it is misleading. 

some supposed credible report debunks it by saying it's unrealistic to be able to get yourself above 56°.

Although admitting the temp does kill the virus in a lab.

main point to highlight i think is the 56° doesn't fix the symptoms caused by the virus and that was the whole basis for the debunking.

in summary. there seems to be truth to it but it is misleading

[alanrchase]

I become skeptical when I see claims that it can't survive above 86f. Body temperature is about 96f, how does it manage to survive that?

[Estrada]

I was involved in solving the source of the Legionella outbreak in the UK back in the '80s, working in conjunction with Porton Down Germ Warfare Establishment. I also have written technical manuals for airconditioning systems and designed water and waste treatment systems. The outside temperature (average 35C) and humidity (80%R.H) will not allow the Corona Virus to survive more than a few hours. At low temperatures and low humidity it can survive for up to 28days. Inside airconditioned shopping malls, offices and other buildings with centralised Ventilation systems with de-humidifiers, the wrong setting can allow the virus to survive a long time (see graph). With the VAC sytems set correctly, this will help prevent transmission.

 

[Estrada]

4 minutes ago, alanrchase said:

I become skeptical when I see claims that it can't survive above 86f. Body temperature is about 96f, how does it manage to survive that?

Because it is outside the body (host).

 

[nervona81732]

Buy a simple hair blow dryer and apply heat (133 degree's F ) to heat the four 4 nasal cavities 2 upper 2 lower and sustain 133 d for a period of time ( up to you ) spray bottle with nam ken to cool the facial skin while treating yourself with 133 f , stand by ( while this fragile virus melts from the heat ( very fragile fat based outer membrane ) and repeat. A Sauna would do it to. 

The genetic ( engineered on purpose ) inside the fat based outer membrane collapses on it's self .

The fact that the cell membrane ( protection of the engineered genetic material ) will be exposed and vanish for it does not have protection from the outer membrane which does have receptors that ARE respiratory specific ( targeting the elderly , pre-existing , on heavy BIG PHARMA poisonous meds, and there are exceptions but obscure ). It's up to you but PANIC ( lowers your immune system ) Vita C, Vita D SUN SUN SUN ( no sun screen..........) Eat right and just use come sense ( if there is anyone out there like that ) live not in fear and take charge of your own <deleted>. Cheers have a great day. In Issan and feel safe.

 

 

[Aspaltso]

42 minutes ago, alanrchase said:

I become skeptical when I see claims that it can't survive above 86f. Body temperature is about 96f, how does it manage to survive that?

I've heard this argument before, and it makes sense. However there's one reason why it may survive on a body longer,  and not on a surface or thing. That reason is that your body is a living thing, with living skin cells, and that's what viruses need to survive. So even though your body temp is 96 degrees Fahrenheit, the fact that the virus is on living cells may account for something.

[Aspaltso]

As mentioned in a previous comment. Hopefully the combination of social distancing measures, and the weather will reduce transmissions in Thailand.

[mixed]

No reports of transmission from the protests? I think the last one was mid-March. Everyone crammed together, it was hot and all had masks.

 

[DrTuner]

Your body regulates your temperature by sweating and through blood circulation. Forget blowdryers unless you want to cause burns on your mucuous membranes.

 

Finns have gone to sauna for centuries ( I am one and I do have a sauna ) and there's no evidence of bathing in hot helping with viral infections, other than the age old saying: If sauna, booze and tar won't kill it, you're toast ( no, don't start drinking tar either ).

Edited March 25, 2020 by DrTuner

[PETERTHEEATER]

Why don't they load the virus into the Thai Immigration computer then no one will get it....

[Iron Tongue]

AVERAGE HUMIDITY IN WUHAN, CHINA: 80%

 

AVERAGE HUMIDITY IN MILAN, ITALY: 90%

 

So what happened there?

[Nyezhov]

Didnt anybody do HS science?

 

Once, we swabbed snot on to an aluminum plate and measured the bacteria with our kiddie microscopes as it set out in the sun. You know what happened as it got hotter (in the USA) dont you?

 

UV light is a recognized way to sterilize. Kills em dead.

 

Two ways to catch the virus:

 

Someone spews it on you.

Someone spews on a surface that you touch and then when you lick your fingers after some drippy chili crab, ya get it.

 

Heat doesnt mean much to a direct spew.

 

But think about the difference between these scenarios.

 

Milan Italy: Vito Genovese blows snot allover his fingers, then opens the door inside a train station in cool conditions.

 

Bangkok Thailand: Porn Wamasuttachanwit picks her nose, then opens the door of a massage parlour to enter. its 29 degrees and the handle is in partial  sun.

 

Siem Reap Thailand: Jaques Strappe from Paris sneezes on the metal rail near the tourist gate at Angkor Wat. 35 degress and bright sun.

 

Ever have metal almost burn you in the tropics? If you flinch, will a virus live thereon?

 

Logically, tell me where I am more likely to get the China flu if I come along 7 hours later and touch the surfaces set forth above.

 

The debate is not whether the virus will die off as the UV increases, but how that will slow the spread. I think it will and I think most scientist will agree.

Edited March 25, 2020 by Nyezhov

[stbkk]

I did read somewhere that the heat and humidity makes it more difficult for the airborne droplets that contain the virus to stay airborne, and consequently (in theory) they would infect fewer people.

 

Seems to make some sense, and would explain the slightly lower infection rates in hotter countries. Although I have no confidence in the government figures from Thailand, at least.

 

[tomazbodner]

59 minutes ago, Iron Tongue said:

AVERAGE HUMIDITY IN WUHAN, CHINA: 80%

 

AVERAGE HUMIDITY IN MILAN, ITALY: 90%

 

So what happened there?

Near 0C temperature and little or no sunlight?

[natway09]

The virus does not last long in direct sunlight

[Tayaout]

Even if heat and humidity slow down the virus, sharing a spoon and a drink counter that. ????

[Nyezhov]

1 hour ago, natway09 said:

The virus does not last long in direct sunlight

Yeah go lay out in the sun in a field in Isaan and see how long you last ????

 

[DrTuner]

4 hours ago, Nyezhov said:

Didnt anybody do HS science?

 

Once, we swabbed snot on to an aluminum plate and measured the bacteria with our kiddie microscopes as it set out in the sun. You know what happened as it got hotter (in the USA) dont you?

 

UV light is a recognized way to sterilize. Kills em dead.

 

Two ways to catch the virus:

 

Someone spews it on you.

Someone spews on a surface that you touch and then when you lick your fingers after some drippy chili crab, ya get it.

 

Heat doesnt mean much to a direct spew.

 

But think about the difference between these scenarios.

 

Milan Italy: Vito Genovese blows snot allover his fingers, then opens the door inside a train station in cool conditions.

 

Bangkok Thailand: Porn Wamasuttachanwit picks her nose, then opens the door of a massage parlour to enter. its 29 degrees and the handle is in partial  sun.

 

Siem Reap Thailand: Jaques Strappe from Paris sneezes on the metal rail near the tourist gate at Angkor Wat. 35 degress and bright sun.

 

Ever have metal almost burn you in the tropics? If you flinch, will a virus live thereon?

 

Logically, tell me where I am more likely to get the China flu if I come along 7 hours later and touch the surfaces set forth above.

 

The debate is not whether the virus will die off as the UV increases, but how that will slow the spread. I think it will and I think most scientist will agree.

Good analogies. However I'll play devil's advocate:

 

Isaan Thailand: Somchai Whattanoporn drinks in a circle of 35 friends all shoutings and spitting at each other at a cock fight with their newly arrived buddied from BKK

 

Bangkok Thailand: Noi Wassup spends her days at a Bangkok mall stuffing her face at a conveyor belt Japanese buffet

 

Yai Maibpenrai: Eats in a circle of friends on the floor sharing the communal dishes in the middle each with their own spoon dipping into the grub

 

Plenty of direct modes of transmission available. And it's rainy season soon when they'll huddle in closed quarters during the showers. 

Edited March 25, 2020 by DrTuner

[Nyezhov]

22 minutes ago, DrTuner said:

Good analogies. However I'll play devil's advocate:

 

Isaan Thailand: Somchai Whattanoporn drinks in a circle of 35 friends all shoutings and spitting at each other at a cock fight with their newly arrived buddied from BKK

 

Bangkok Thailand: Noi Wassup spends her days at a Bangkok mall stuffing her face at a conveyor belt Japanese buffet

 

Yai Maibpenrai: Eats in a circle of friends on the floor sharing the communal dishes in the middle each with their own spoon dipping into the grub

 

Plenty of direct modes of transmission available. And it's rainy season soon when they'll huddle in closed quarters during the showers. 

Not going to deny any of that, and that has no effect on what I am saying. IM saying that for folks who practice the simple rules of hygeine and pay attention to the distancing etc will have less of a chance of catching it from surfaces as the weather warns.

 

As to the USA, as long as Im still here, there wont be a lot of spoon dipping in other folks food. Or even running the buffet line with my own runcible spoon. Dont worry folks, Im far away.

 

Its like AIDs. Dont shoot up and dont take in it the you know where and your chances of getting it are small.

[tjinks]

Fake news.

[ukrules]

10 hours ago, Iron Tongue said:

AVERAGE HUMIDITY IN WUHAN, CHINA: 80%

 

AVERAGE HUMIDITY IN MILAN, ITALY: 90%

 

So what happened there?

It's called 'relative' humidity for a reason, but now is not the time to educate you. Begin your journey by learning what it's 'relative' to.....

 

Also see this, it's 3pm in the afternoon in Milan right now - one of the hottest times of the day :

 

Edited March 25, 2020 by ukrules

[DrTuner]

50 minutes ago, ukrules said:

It's called 'relative' humidity for a reason, but now is not the time to educate you. Begin your journey by learning what it's 'relative' to.....

Information is always a good thing so I'll add the pointers:

 

https://en.wikipedia.org/wiki/Relative_humidity

 

 

I also have first hand experience with the dew point having worked outside in construction. Had to wait many a morning for the dew to disperse as the air got warmer.

 

This might bring a component of contageous hours within a day to the mix. It's wet after a cool night, to point the obvious.

Edited March 25, 2020 by DrTuner