Vietnam has taken this epidemics 10x more seriously than Italy, that could just be the difference.

They are testing as much as they can, everybody who had contact with infected people are tracked down and quarantined, streets where you had infected people are closed down and disinfected, almost everybody wear masks, you have temperature checks & hydroalcoholic gel available in public areas, schools are fully closed since early January.

Yes. However, there's also no travel restriction between Cambodia and Vietnam, significant cross-border traffic, and Cambodia is not "taking it nearly as seriously" as Vietnam is.

If Vietnam had the transmission going on that Italy does, the case-tracking and quarantining would be a lot harder, and I just don't buy that the other things (masks, forehead temperature checks[0], hand sanitizer that hardly anyone knows how to use properly) have much of an impact.

There has to be some much larger factor than those at play (and this study suggests what that factor could be).

[0] I encourage people to ask or look what the reading is when getting these checks. About a third of the time when I get a forehead temperature check, the reading is totally nonsensical, like 31C, but the person just waves me through since it's under the threshold. I'm skeptical of the efficacy of a test that is this inaccurate.

I live in Vietnam, maybe you too. It is true that Government here is being very restrictive, controlling flights, quarantine people, etc... But its true that during early January, still many people coming from China came to Vietnam, also people comng from other south east asians. During second half of february there were no restrictions for visa exemption for tourists, thousands came from Spain, Italy, Germany, UK... What I mean if this was Italy, Austria, Norway, the virus would have been unstoppable. We would have case everywhere , thousadns, same should be Singapore, Thailanda, laos, etc... Its very clear that the virus can be transmited here? YES, of course but only thorugh very direct contact, what is that is happening. I am sure the weather played a big role and virus is not stable for long time when exposed. I am sure also, that all this here is creating a huge oportunity of propaganda for the socialist government, they make popultaion feel fear all the time, all the people here think they will die if they catch the virus so they see like sheeps the government as an angel. They are taking too strict measurements and the damage here economically speaking is already HUGE. An example how to manage this is Singapore. They always had imported cases, and few direct contact cases from this imported cases. But they still run the country as normal as possible with not too strict measures. Here they are literally crazy. Of course, personal opinion, cheers

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.

Sorry if I was unclear. I was trying to say that it seems clear to me intuitively that something other than "taking it seriously" is reducing the transmission rates in VN. It's just a "feeling" -- but this study seems to provide some (thin) evidence supporting it.