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Preexisting Herd Immunity?


ExpatOilWorker

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Could Thailand's, at times unbelievable, success in containing the coronavirus really be down to a preexisting herd immunity?

 

Indeed, human populations in Cambodia, Laos, Thailand and Vietnam appear to be much less affected by the Covid-19 pandemic than other countries in the region, such as Bangladesh, Myanmar, Malaysia, the Philippines and Indonesia. This suggests that the populations of these four countries may be benefiting from a level of herd immunity to Sarbecoviruses.

 

https://theconversation.com/in-2010-a-virus-similar-to-sars-cov-2-was-already-present-in-cambodia-154491

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Its entirely possible. 

 

Back towards the tail end of 2019 and very early on 2020 there were reports of increased cases of viral pneumonia.

 

This would tie in with the sheer volume of tourists entering from China - its difficult to imagine that the SARS-CoV-2 virus was not brought into Thailand and carried / spread in huge numbers. 

 

There are additional theories that ‘East Asians’ have a genetic advantage with 4 specific Halpotypes (groups of genes) missing in East Asians that have been identified in as being prevalent / present in those who develop serious Covid-19 symptoms. 

 

The absence of testing in Thailand (except arrivals) presents a huge gap in date from which more valid conclusions could be drawn. 

 

 

It does seem as though Thailand has dodged a bullet - but the lockdowns, early mask wearing and general repose, curfews  may well have contributed to the success Thailand has seen so far. 

 

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Looking at the map, I think this has been mistranslated:

Quote

The new virus from Cambodia was detected in a bat species endemic to Southeast Asia that does not extend beyond Yunnan, where the two previous bat SARS-CoV-2-like viruses were found.

Beyond should be into.

 

That para seems to refer to R shameli, which is the only one of the three bat species with a range confined to Thailand, Laos, Cambodia and Vietnam.

 

But viruses similar to SARS-COV-2 have also been sequenced from both the other two species on that map, and they have ranges that cover most of Myanmar and southern China (almost reaching to Wuhan).

 

And:

Quote

Chinese researchers have been searching for Sarbecoviruses throughout the country for about 15 years. They found more than 100 SARS-CoV-like viruses but only two related to SARS-CoV-2.

So it sounds like these other bats had viruses similar to the one found in R shameli. Shouldn't this also have conferred immunity to the human populations in the much larger ranges of those additional two species?

 

Arguably some effect is visible in the data for Myanmar; but the range for R afinis extends pretty close to Wuhan, if you take into account how much domestic travel goes on in China, and there wasn't much evidence of pre-existing herd immunity in Wuhan.

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35 minutes ago, richard_smith237 said:

Its entirely possible. 

 

Back towards the tail end of 2019 and very early on 2020 there were reports of increased cases of viral pneumonia.

 

This would tie in with the sheer volume of tourists entering from China - its difficult to imagine that the SARS-CoV-2 virus was not brought into Thailand and carried / spread in huge numbers. 

 

There are additional theories that ‘East Asians’ have a genetic advantage with 4 specific Halpotypes (groups of genes) missing in East Asians that have been identified in as being prevalent / present in those who develop serious Covid-19 symptoms. 

 

The absence of testing in Thailand (except arrivals) presents a huge gap in date from which more valid conclusions could be drawn. 

 

 

It does seem as though Thailand has dodged a bullet - but the lockdowns, early mask wearing and general repose, curfews  may well have contributed to the success Thailand has seen so far. 

 

This topic was discussed a lot last summer when it was becoming apparent that Thailand and its neighbours had got off very lightly. Cambodia, Vietnam, Laos and ourselves all had many Chinese tourists flooding in for 2, maybe 3 months before anyone had even heard of the Covid virus, never mind given it a name.

 

Personally, I think the chances of a number of infected tourists coming down to SEA and NOT spreading the infection are very small indeed. Yes, I think there is a very good chance that a 'silent epidemic' passed through the region and left it with a degree of herd immunity.

 

Neither is this the only region. Studies have shown that the virus was spreading in Italy as early as September 2019! But conditions there, particularly climatic were very different, resulting in a much more serious situation.

 

https://www.weforum.org/agenda/2020/11/coronavirus-italy-covid-19-pandemic-europe-date-antibodies-study/

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1 hour ago, richard_smith237 said:

Its entirely possible. 

 

Back towards the tail end of 2019 and very early on 2020 there were reports of increased cases of viral pneumonia.

 

This would tie in with the sheer volume of tourists entering from China - its difficult to imagine that the SARS-CoV-2 virus was not brought into Thailand and carried / spread in huge numbers. 

 

There are additional theories that ‘East Asians’ have a genetic advantage with 4 specific Halpotypes (groups of genes) missing in East Asians that have been identified in as being prevalent / present in those who develop serious Covid-19 symptoms. 

 

The absence of testing in Thailand (except arrivals) presents a huge gap in date from which more valid conclusions could be drawn. 

 

 

It does seem as though Thailand has dodged a bullet - but the lockdowns, early mask wearing and general repose, curfews  may well have contributed to the success Thailand has seen so far. 

 

datA

 

respoNse

 

It's ok, the rest makes an interesting theory.

 

 

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2 hours ago, ExpatOilWorker said:

Could Thailand's, at times unbelievable, success in containing the coronavirus really be down to a preexisting herd immunity?

 

I've been saying this for months now. No way Thailand or any country could stop viral spread by closing the airports and masking the population.

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2 hours ago, ExpatOilWorker said:

Could Thailand's, at times unbelievable, success in containing the coronavirus really be down to a preexisting herd immunity?

 

Indeed, human populations in Cambodia, Laos, Thailand and Vietnam appear to be much less affected by the Covid-19 pandemic than other countries in the region, such as Bangladesh, Myanmar, Malaysia, the Philippines and Indonesia. This suggests that the populations of these four countries may be benefiting from a level of herd immunity to Sarbecoviruses.

 

https://theconversation.com/in-2010-a-virus-similar-to-sars-cov-2-was-already-present-in-cambodia-154491

 

It's possible.

 

Asymptomatic/mild infection may also indicate pre-existing immunity- at least partially.

 

Nothing new in this though.

 

I agree there have been very similar viruses doing the rounds.

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8 hours ago, NorthernRyland said:
10 hours ago, ExpatOilWorker said:

Could Thailand's, at times unbelievable, success in containing the coronavirus really be down to a preexisting herd immunity?

 

8 hours ago, NorthernRyland said:

 

I've been saying this for months now. No way Thailand or any country could stop viral spread by closing the airports and masking the population.

Or by lying about the numbers as many still seem to think.

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According to the map R. shameli hardly occurs in Vietnam. 

However, I think the matter could be settled by doing immunological studies in various countries. As an easy test one could first design simple antibody tests (by lateral flow) against the two claimed horse shoe bat viruses as well as COVID-19 (the latter have become much more reliable recently though still far from perfect).  More advanced studies could look at cross-reactivity of existing antibodies (if these actually occur) against the bat viruses towards SARS-CoV-2.

And note that some SEA countries are not alone in having low COVID incidences/capita. As an example, the value for Taiwan is less than two times higher than Vietnam (source: worldometer).  

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I have read over a month ago, that scientists do suspect a similar virus was in SEA some 15-20k years ago and gave genetic immunity.

 

but even getting through some other viral infection, like dengue or any other oriental virus, might boost immune system. Local people get dengue every 9 years (statistically), with 80% asymptomatic, 15% mild symptoms.

 

there is also a theory, that use of anti-malaria and other anti-parasitic medicines in africa, and in some parts of asia, also protects them from covid.

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Would imagine the fact that Indonesia having 1.1 million infections and  31,000 deaths,  philippines having 500,000 infection and 11,000 deaths, Malaysia having 250,000 infections and 800 deaths is a clear indication of a Thai herd immunity being plain nonsense. 

 

thailand has supposedly 600,000 die every year of all reasons.

 

I've yet to see any data coming out of Thailand on the testing of the deceased.

 

If worldometer was correct on Thailand only doing 1.2 million tests, then they have either only tested 600,00 live people or 1.2 million live people and no dead people to see if they died of covid.

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54 minutes ago, RichardColeman said:

Would imagine the fact that Indonesia having 1.1 million infections and  31,000 deaths,  philippines having 500,000 infection and 11,000 deaths, Malaysia having 250,000 infections and 800 deaths is a clear indication of a Thai herd immunity being plain nonsense. 

they are more populated than thailand and they are not budhist (greeting not wai, but hand shaking or even hugging/kissing). 

Also obligatory sunday mass and friday/daily prayer in mosques are contributing to virus spread - vide korean christian church, with singing. Deep believers tend to ignore danger of virus and don't put feight in social distancing, wearing masks and other virus hygiene   

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3 hours ago, RichardColeman said:

Would imagine the fact that Indonesia having 1.1 million infections and  31,000 deaths,  philippines having 500,000 infection and 11,000 deaths, Malaysia having 250,000 infections and 800 deaths is a clear indication of a Thai herd immunity being plain nonsense. 

 

thailand has supposedly 600,000 die every year of all reasons.

 

I've yet to see any data coming out of Thailand on the testing of the deceased.

 

If worldometer was correct on Thailand only doing 1.2 million tests, then they have either only tested 600,00 live people or 1.2 million live people and no dead people to see if they died of covid.

No sign of overcrowded hospitals. Or the medical system in general being overwhelmed. 

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2 hours ago, internationalism said:

they are more populated than thailand and they are not budhist (greeting not wai, but hand shaking or even hugging/kissing). 

Also obligatory sunday mass and friday/daily prayer in mosques are contributing to virus spread - vide korean christian church, with singing. Deep believers tend to ignore danger of virus and don't put feight in social distancing, wearing masks and other virus hygiene   

But by your reasoning, that would mean that masks and social distancing should be very effective. And as the quashing of the latest wave of contagion shows, they do work.

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1. A very weak point is that the authors do not provide any proof that the mentioned bat viruses can infect humans.

 

2. Furthermore, when it comes to bats, these occur world-wide. An interesting article describes attempt to predict which wildlife species could harbour betacoronaviruses https://www.biorxiv.org/content/10.1101/2020.05.22.111344v3.full.pdf

 

3. If  for instance 10,000 persons/year died in Thailand with COVID-19 you would not notice that in the total mortality figures. Even in some European countries you cannot see excess mortality outside the 95% CI range, check Norway and Finland for instance on euromomo.eu where data go back 5 years or so. And no, you cannot calculate how many people died with COVID from the graphs (they are mortality from all causes) but you do get a good idea which countries have been affected badly and in almost all cases, reported deaths with COVID are significantly less than excess mortality so data are realistic. Data may be lowered by less flu deaths, road victims or increased by people that could/would not be treated for other diseases, etc (nicely explained in ourworldindata.com).  

 

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