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Comment by codebolt | Hacker News Reader

I have in-laws in Nigeria. We just tipped them off a couple of days ago that now might be a good time to buy some Chloroquine and keep at the house, in case the situation gets worse. This is a commonly known medicine down there, that you can get from pharmacies without prescription.

But based on what we're seeing so far, it seems plausible that this virus prefers cooler northern climates. So hopefully it will turn out to be an unnecessary precaution.

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In the east coast of Spain we have had great weathee (25+ degrees celsius) and it didn't seem to greatly influence transmission speed :(

The numbers so far suggest you need tropical heat and humidity to slow down transmission speed. That would need to be 35C+ weather, and no air conditioning.

Before I've read you message I was sure that dry air slows down transmission speed. But indeed, it's humidity https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3551767

Sorry, I'm now picturing email offers from Nigerians that I would openly welcome.

Citation needed on it preferring colder climates. My own quick glimpse of the global numbers showed plenty of equatorial cases per capita. Many aren’t rigorously tested populations, too.

It's something I first read from the Goldman Sachs client call notes that has been circulating:

https://www.forbes.com/sites/abrambrown/2020/03/16/the-priva...

Certainly not the best citation, and I have no idea where GS gets their analyses, but seems plausible enough that I'm at least hoping there could be some truth to it. See e.g. India, the virus doesn't seem to have taken off there despite a few early cases.

If it's wrong, I fear things could get really bad, especially in heavily populated cities like Lagos.

I think this presentation is a great source of facts.

https://drive.google.com/file/d/1DqfSnlaW6N3GBc5YKyBOCGPfdqO...

Weather: Maybe 10 oF increases the doubling time 2x (steady-state reduction in exterior virus levels by 50% per Pubmed 22312351, plus reducing time × concentration of people indoors).

I don't think a paper about SARS-CoV-2 and temperature has been written yet (that I've seen), but people are hoping it reacts like SARS-CoV. See here: https://www.ncbi.nlm.nih.gov/pubmed/22312351

Keep in mind, that doesn't mean zero cases in hot weather, just that it is less contagious.

“ It may also explain why some Asian countries in tropical area (such as Malaysia, Indonesia or Thailand) with high temperature and high relative humidity environment did not have major community outbreaks of SARS.”

Iirc, Maylasia has a pretty strong breakout on its hands. They recorded their first death today and are at something like 670 cases. I think their double rate was 2-3 days. Edit-it’s 1 day today. See link. Not good news I think for the hypothesis.

https://ourworldindata.org/coronavirus

The rapid transmission in industrialized countries is most likely helped by the daily indoor concentration of people in the big cities, during commute, in large schools and workplaces. Large cities in Africa will surely get it to some extent, but the spread might be slower since Africans don't spend as much time indoors, and the rural communities are already practicing "social distancing" to some degree.

I think you have a very Hollywood view of African societies...

Having lived in African countries for more than 5 years I don't rely on Hollywood for my sources.

I'd offer the Ebola outbreak as a counter-example.

Ebola is different: It does not spread over air like the Corona virus.

The Ebola virus " spreads to people initially through direct contact with the blood, body fluids and tissues of animals. Ebola virus then spreads to other people through direct contact with body fluids of a person who is sick with or has died from EVD". [0]

[0] https://www.cdc.gov/vhf/ebola/about.html

Only 2 Ebola outbreaks have had more than 1000 infected people.

This thing is in the early stages still and there are already 7x more recorded cases than the largest Ebola outbreak.

Nirobi, Metro Area Population 10 million

https://www.civitatis.com/en/nairobi/

Compare:

Largest cities in Africa

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

Largest cities in USA

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

It's not a matter of big cities only. People in the big cities in industrialized countries spend their time indoors with large crowds to a much higher degree. It indicates that the spread will be slower in Africa (while not absent)

What exactly do you expect those 10M people to do during the day?

> But based on what we're seeing so far, it seems plausible that this virus prefers cooler northern climates. So hopefully it will turn out to be an unnecessary precaution.

Wuhan has temps around 50F-75F (~15C-22C). Certainty not hot, but not a cooler climate given how it's still winter in this hemisphere.

Italy and Spain aren't known for being especially cold either, mountainous areas notwithstanding.

All of these locations are still cooler northern climates. I agree that they're not exactly cold.

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