Donate to Remove ads

Got a credit card? use our Credit Card & Finance Calculators

Thanks to johnstevens77,Bhoddhisatva,scotia,Anonymous,Cornytiv34, for Donating to support the site

Can anything be learned from Chile?

The home for all non-political Coronavirus (Covid-19) discussions on The Lemon Fool
Forum rules
This is the home for all non-political Coronavirus (Covid-19) discussions on The Lemon Fool
Julian
Lemon Quarter
Posts: 1385
Joined: November 4th, 2016, 9:58 am
Has thanked: 532 times
Been thanked: 676 times

Can anything be learned from Chile?

#402000

Postby Julian » April 6th, 2021, 12:36 pm

I know that a few people here get exasperated by negative posts and this is not intended to be the start of a doom-and-gloom thread. My personal opinion is that I really am not able at this time to even form a decent personal hunch about how the rest of 2021 will pan out. I assume the answer is anywhere on the spectrum from best case no real third wave at all, or if it happens it is cases only with very few hospitalisations or deaths and no new variants of concern arising through to a worst case scenario of variants cutting through the vaccine defences to a significant extent and the UK getting a third wave at least as bad as the one we're just coming out of presumably needing a third similarly severe national lockdown to contain it. There are just too many loose ends (others might call those potential concerns) regarding the current situation that makes me unable to even have much of a hunch about where on that spectrum we will end up.

All of my loose ends relate to vaccines and variants, in particular efficacy of the various vaccines against severe disease arising from the new variants of concern and efficacy of the various vaccines against transmission for even the current B.1.1.7 variant let alone the SA/Brazil/other variants. Here Chile seems to be a very interesting and somewhat alarming test case and I wonder what other people here think about what is going on there. Is it a cause for genuine concern in terms of what might happen in the UK later this year or might there be peculiar factors in Chile that are causing it to see this second wave, severe enough for it to re-enter lockdown, despite it's seemingly extremely good vaccination program?

Here is just one article about the Chile situation from just over a week ago - https://www.theguardian.com/global-deve ... on-success

I was actually totally unaware of this news until I watched Boris's news conference yesterday and one of the journalists asking a question mentioned it. Is it just me or has this had relatively low billing in the UK media?

For convenience some selected (by me) key points from the article above are...

Despite mounting the world’s fastest per-capita Covid-19 vaccination campaign, Chile has been forced to announce strict new lockdowns as it plunges deeper into a severe second wave of cases which is stretching intensive care capacity.
...
Nearly half of the South American country’s population has received at least one vaccine dose, but on Friday, Chile recorded 7,626 new cases over a 24-hour period – the highest total at any point during the pandemic – and it is now approaching 1m cases in total.
...
... Only 169 intensive care beds remain available nationwide – an occupancy rate of more than 95%. ...
...
More than 6 million people have received at least one dose of either the Chinese Sinovac or US Pfizer-BioNTech vaccine, and 3.2 million have had both jabs.
...
“The issue with communication is that it hasn’t been consistent across government,” explained Aguilera. “While the health ministry has repeatedly called on people to look after themselves, the economy minister has been opening casinos, gyms and cinemas.”
...
However, with international travel still allowed, many Chileans took advantage of cheap flights to Miami, Brazil, the Dominican Republic and other destinations, causing the government to tighten restrictions for returning travellers – but not until after the summer holiday season was over.
...


Probably clutching at straws but one explanation that would be encouraging for the UK would be if the Sinovac vaccine isn't particularly good and/or if widespread handling issues with the Pfizer vaccine blunted its average efficacy. Then again, we still have unanswered questions about the efficacy of one of our mainstay vaccines (Oxford/AZ) regarding efficacy against the SA variant in terms of severe and fatal disease.

Another factor is Chile at least being on the same continent as Brazil so maybe far more exposure to an E484K-carrying variant such that it is very prominent in the country whereas in the UK we do seem to be keeping the SA variant in bay. As I suggested in a reply to Mike (Mike4) yesterday the PM press conference yesterday did give numbers for new variants in the UK and they are on slide 4 from yesterday's briefing (https://assets.publishing.service.gov.u ... ation_.pdf).

From that data on total "genomically confirmed and probable" cases we have 544 out of a total of 173,586 being variants carrying the E484K mutation (that's 0.3134%) and the new cases since 24th March is +62 E484K carrying cases out of a total of 17,575 new cases so that's 0.3528% of new cases being E484K carrying variants. That actually looks pretty encouraging to me, the percentage of new variants of concern is still very low in the UK and that means that, if it stays that way, then even if the AZ vaccine is way less effective against those variants the overall reduction in efficacy across the whole UK vaccinated population will be low. So far the rate of E484K carrying variants in new cases since 24th March is pretty much in line with the overall percentage so these new variants, at least for now, don't seem to be building much of a beachhead here in the UK but if they are able to escape the vaccines far better than the B.1.1.7 variant can then that balance could change over time - how much time I have no idea. The press briefing also said that a lot of those E484K positives were from quarantine testing of incoming travellers from red zones and to me those positives seem far less worrying since the carriers did not get into the community but went straight into enforced hotel quarantine.

My personal take-away from this is that we really shouldn't have too much hope for much summer international travel, and maybe it is partly this Chile experience that is causing the government to send out quite so many signals to this effect at the moment. Personally I also wouldn't be at all surprised to see at least the 21st June final unlock stage delayed or happen as scheduled but not be quite such a big relaxation as is currently proposed. I also wonder whether the 17th May unlock really will allow rule-of-6 meetings in private homes as is currently intended (https://www.gov.uk/government/publicati ... 21-summary). To me it would seem to make sense to assess the effect of rule-of-6 in theoretically Covid-safe controlled indoor environments such as pubs, restaurants etc for 5 weeks and maybe delay blanket rule-of-6 indoors until the 21st June unlock stage. ANd maybe booster shots in September onwards are more essential than I was perhaps thinking before I became aware yesterday of what was going on in Chile.

Sorry, long post, but I think Chile is an important "battlefield" to analyse when it comes to the fight against SARS-CoV-2 especially when looking at a strong vaccination program vs the virus.

- Julian

redsturgeon
Lemon Half
Posts: 8910
Joined: November 4th, 2016, 9:06 am
Has thanked: 1309 times
Been thanked: 3665 times

Re: Can anything be learned from Chile?

#402003

Postby redsturgeon » April 6th, 2021, 12:45 pm

Interesting questions and similar to my own at the moment. On R4 this morning I heard scientists were warning of a third wave larger than the second in the UK if we relax measures too quickly this summer...although I did not hear when they would expect this to strike.

Like you I would be very surprised if foreign holidays are relaxed enough for most people to travel abroad and the fact that tests would be required both pre and post any holiday would rule this out for many people purely on a cost basis. Personally I think this is a good thing and I am somewhat surprised that people place so much store on their fortnight in the Costas.

Perhaps our learnings should be from the like of China and South Korea etc who seem to have things under control, effectively stomping on any new wave before it takes hold.

John

Lootman
The full Lemon
Posts: 18674
Joined: November 4th, 2016, 3:58 pm
Has thanked: 628 times
Been thanked: 6559 times

Re: Can anything be learned from Chile?

#402033

Postby Lootman » April 6th, 2021, 2:15 pm

redsturgeon wrote:I would be very surprised if foreign holidays are relaxed enough for most people to travel abroad and the fact that tests would be required both pre and post any holiday would rule this out for many people purely on a cost basis. Personally I think this is a good thing and I am somewhat surprised that people place so much store on their fortnight in the Costas.

Perhaps our learnings should be from the like of China and South Korea etc who seem to have things under control, effectively stomping on any new wave before it takes hold.

But there is a lot more to travel than just the Benidorm crowd. There are people who need to travel because their family is geographically split, or for work or study, or for emergencies and crises, and so on.

Boris today said that he supports the idea of allowing the cheaper lateral flow tests for travel from countries that will be designated in the "green" zone, with no need for isolation.

The Amber zone would require tests and self-quarantine as now. And the red zone will required enforced hotel quarantine.

A reasonable compromise? The risk is not visiting countries with low infection rates and/or a successful vaccination programme. I feel sure your son in Iowa would benefit from a travel corridor between the UK and the US, based on the advances both nations have made on vaccinations, as an example.

redsturgeon
Lemon Half
Posts: 8910
Joined: November 4th, 2016, 9:06 am
Has thanked: 1309 times
Been thanked: 3665 times

Re: Can anything be learned from Chile?

#402063

Postby redsturgeon » April 6th, 2021, 4:02 pm

Lootman wrote:
redsturgeon wrote:I would be very surprised if foreign holidays are relaxed enough for most people to travel abroad and the fact that tests would be required both pre and post any holiday would rule this out for many people purely on a cost basis. Personally I think this is a good thing and I am somewhat surprised that people place so much store on their fortnight in the Costas.

Perhaps our learnings should be from the like of China and South Korea etc who seem to have things under control, effectively stomping on any new wave before it takes hold.

But there is a lot more to travel than just the Benidorm crowd. There are people who need to travel because their family is geographically split, or for work or study, or for emergencies and crises, and so on.

Boris today said that he supports the idea of allowing the cheaper lateral flow tests for travel from countries that will be designated in the "green" zone, with no need for isolation.

The Amber zone would require tests and self-quarantine as now. And the red zone will required enforced hotel quarantine.

A reasonable compromise? The risk is not visiting countries with low infection rates and/or a successful vaccination programme. I feel sure your son in Iowa would benefit from a travel corridor between the UK and the US, based on the advances both nations have made on vaccinations, as an example.


Strangely enough since we are in the business of Covid testing for travel I am fully aware of the need for travel beyond the Benidorm crowd. Thanks for the information.

The lateral flow test may be a little cheaper but if the government hopes to retain any degree of control on the validity of the testing then the cost will still be significant.

The test will have to be overseen by an authorised person who will be then need to confirm that the test has been properly carried out on the person for who any certificate is given.

We do not charge much less for providing a certificated lateral flow test than we do for PCR testing, the process actually takes us longer to do although the result is available more quickly for the client.

As we also know, the lateral flow tests are less accurate than the PCR tests and no isolation after travel to a green zone does not necessarily mean no day 2 and 8 testing.

John

GrahamPlatt
Lemon Quarter
Posts: 2059
Joined: November 4th, 2016, 9:40 am
Has thanked: 1032 times
Been thanked: 823 times

Re: Can anything be learned from Chile?

#402067

Postby GrahamPlatt » April 6th, 2021, 4:16 pm

Rapid, point‐of‐care antigen and molecular‐based tests for diagnosis of SARS‐CoV‐2 infection

https://www.cochranelibrary.com/cdsr/do ... .pub2/full

"At 5% prevalence using data for the most sensitive assays in symptomatic people (SD Biosensor STANDARD Q and Abbott Panbio), positive predictive values (PPVs) of 84% to 90% mean that between 1 in 10 and 1 in 6 positive results will be a false positive, and between 1 in 4 and 1 in 8 cases will be missed. At 0.5% prevalence applying the same tests in asymptomatic people would result in PPVs of 11% to 28% meaning that between 7 in 10 and 9 in 10 positive results will be false positives, and between 1 in 2 and 1 in 3 cases will be missed."

9873210
Lemon Slice
Posts: 984
Joined: December 9th, 2016, 6:44 am
Has thanked: 226 times
Been thanked: 296 times

Re: Can anything be learned from Chile?

#402121

Postby 9873210 » April 6th, 2021, 7:18 pm

This makes it obvious that 50%* is no where near herd immunity. (* Since first dose is not completely effective perhaps effectively 30% immunity.)

Nothing to learn here since we've known this for the best part of a year. Anybody who learned this from Chile is a tad dense. Not as dense as the folks who still think "this summer in Ibiza" is compatible with effective public health policy.

servodude
Lemon Half
Posts: 8271
Joined: November 8th, 2016, 5:56 am
Has thanked: 4435 times
Been thanked: 3564 times

Re: Can anything be learned from Chile?

#402154

Postby servodude » April 6th, 2021, 11:32 pm

GrahamPlatt wrote:Rapid, point‐of‐care antigen and molecular‐based tests for diagnosis of SARS‐CoV‐2 infection


What I'd like to know is whatever happened to the sniffer dogs

EDIT: asking google there's stuff in preprint: https://www.biorxiv.org/content/10.1101/2021.03.05.434038v1.full

- sd

XFool
The full Lemon
Posts: 12636
Joined: November 8th, 2016, 7:21 pm
Been thanked: 2608 times

Re: Can anything be learned from Chile?

#402156

Postby XFool » April 6th, 2021, 11:39 pm

servodude wrote:What I'd like to know is whatever happened to the sniffer dogs

Maybe they all went down with COVID?

http://www.newsweek.com/amplify/9-signs-your-dog-has-covid-19-what-do-about-it

servodude
Lemon Half
Posts: 8271
Joined: November 8th, 2016, 5:56 am
Has thanked: 4435 times
Been thanked: 3564 times

Re: Can anything be learned from Chile?

#402158

Postby servodude » April 6th, 2021, 11:50 pm

XFool wrote:
servodude wrote:What I'd like to know is whatever happened to the sniffer dogs

Maybe they all went down with COVID?

http://www.newsweek.com/amplify/9-signs-your-dog-has-covid-19-what-do-about-it


that would be rough!

AsleepInYorkshire
Lemon Half
Posts: 7383
Joined: February 7th, 2017, 9:36 pm
Has thanked: 10514 times
Been thanked: 4659 times

Re: Can anything be learned from Chile?

#402159

Postby AsleepInYorkshire » April 6th, 2021, 11:52 pm

Chile has only vaccinated 50% of their population with a first dose. They haven't come out of lockdown in steps. They've come out at high speed.

But 50% vaccine coverage at [say] 30-40% blanket cover on those vaccinated and with an R rate above 1 - spells trouble anywhere. Not a vaccine issue. It's a lack of coordination and too many freedoms of movement too quickly. They've messed up and be over-confident?

AiY

servodude
Lemon Half
Posts: 8271
Joined: November 8th, 2016, 5:56 am
Has thanked: 4435 times
Been thanked: 3564 times

Re: Can anything be learned from Chile?

#402164

Postby servodude » April 7th, 2021, 12:26 am

AsleepInYorkshire wrote:Chile has only vaccinated 50% of their population with a first dose. They haven't come out of lockdown in steps. They've come out at high speed.

But 50% vaccine coverage at [say] 30-40% blanket cover on those vaccinated and with an R rate above 1 - spells trouble anywhere. Not a vaccine issue. It's a lack of coordination and too many freedoms of movement too quickly. They've messed up and be over-confident?

AiY


Very probably
- and the tune will probably repeat over in different places
Virus Surge in Michigan Is a ‘Gut Punch’ to Hopes of Pandemic’s End
https://www.nytimes.com/2021/04/01/us/michigan-covid-outbreak.html

Health officials partly attributed the rapid rise in cases to the B.1.1.7 variant that was originally identified in Britain and is widespread in Michigan. But they have also observed a broader return to prepandemic life seen in a relaxing of mask wearing, social distancing and other strategies meant to slow the spread of the virus — many weeks before a substantial portion of the population is vaccinated. On Thursday, Michigan officials announced that they had identified their first case of the P.1 variant, which has spread widely in Brazil and has now been found in more than 20 U.S. states.


- sd

AsleepInYorkshire
Lemon Half
Posts: 7383
Joined: February 7th, 2017, 9:36 pm
Has thanked: 10514 times
Been thanked: 4659 times

Re: Can anything be learned from Chile?

#402262

Postby AsleepInYorkshire » April 7th, 2021, 11:54 am

Covid: Brazil has more than 4,000 deaths in 24 hours for first time
Brazil has recorded more than 4,000 Covid-related deaths in 24 hours for the first time, as a more contagious variant fuels a surge in cases.

The doubt creeps in. If I recall correctly Spanish Flu (which was the largest cause of death in 1918 (ish) outbreak was a variant that appeared later in the process?

Is there some confidence that the current vaccinations can cope with the "Brazilian" variant?

AiY

GrahamPlatt
Lemon Quarter
Posts: 2059
Joined: November 4th, 2016, 9:40 am
Has thanked: 1032 times
Been thanked: 823 times

Re: Can anything be learned from Chile?

#402278

Postby GrahamPlatt » April 7th, 2021, 12:42 pm

I posted this earlier in the thread on the Third Wave: https://www.ft.com/content/a2901ce8-5eb ... df5b386938
(FT but a free read; no login required). Relevant here also.

monabri
Lemon Half
Posts: 8396
Joined: January 7th, 2017, 9:56 am
Has thanked: 1539 times
Been thanked: 3428 times

Re: Can anything be learned from Chile?

#402633

Postby monabri » April 8th, 2021, 3:34 pm

I thought Chile had a small delivery of Pfizer but has, in the main, used Sinovac ( 50% efficacy).

https://www.nbcnews.com/news/latino/chi ... es-rcna505

"Delivering around 225,000 doses a day — mostly of the Chinese Sinovac vaccine ....."

They've currently delivered 11.4m doses ( of which 4.25m is a 2nd jab)....population 19.2 million. So, 38% have had their first jab but mostly of Sinovac.


From Our World in Data https://github.com/owid/covid-19-data/b ... /Chile.csv

Image

The main programme started in February so one would need to allow time for the vaccine to 'do it's stuff. The role out was slow until they got their hands on the Sinovac.

The Guardian talks about the vaccination programme instilling a false sense of security that lead to opening up too quickly ( " what went wrong").

https://www.theguardian.com/world/2021/ ... n-lockdown

Julian
Lemon Quarter
Posts: 1385
Joined: November 4th, 2016, 9:58 am
Has thanked: 532 times
Been thanked: 676 times

Re: Can anything be learned from Chile?

#402878

Postby Julian » April 9th, 2021, 12:27 pm

I agree that the basic error with Chile was unlocking too early but the interesting underlying factor there is that I assume that overconfidence came from an overconfidence in the efficacy of their vaccination program at the point they unlocked. I just found this article reporting on the efficacy of the Sinovac vaccine as measured by observational studies in Chile. The data doesn't look great (and that's probably an understatement)...

Chile has provided a real-time demonstration of the effectiveness of Chinese firm Sinovac’s Covid-19 vaccine, with its vaccination drive results showing it to be 56.5 per cent effective two weeks after the second dose. The findings were in line with Phase 3 trial results of the vaccine in Brazil, which found an efficacy rate of around 50 per cent.

But the study by the University of Chile also found that one dose of the Sinovac jab was only 3 per cent effective against infection, underscoring the need to get fully vaccinated. Efficacy rises to 27.7 per cent within two weeks after the second jab, reaching 56.5 per cent a fortnight later, according to the university.

Chile has vaccinated 7.2 million people to date, with 4.3 million having received their second dose. More than 93 per cent of those who have had both jabs received the Sinovac vaccine. The South American country has also approved the Pfizer-BioNTech and Oxford-AstraZeneca vaccines and, on Wednesday, Chinese company CanSino’s single-dose vaccine was added to the emergency list.


[ Source: https://www.scmp.com/news/china/science ... icacy-data ]

(I note an inconsistency in the above - 1st paragraph "56.5 per cent effective two weeks after the second dose" vs 2nd paragraph "Efficacy rises to 27.7 per cent within two weeks after the second jab, reaching 56.5 per cent a fortnight later". So is 56.5% efficacy reached 2 weeks after the second dose or closer to 4 weeks after?)

According to Wikipedia Chile's population as measured by the 2017 census was 17,574,003.

In light of just how poor the vaccine is, especially after the first dose (3%) but even up to 2 weeks after the second dose (maybe as low as 27.7%? The article is inconsistent as noted above), I can see why the Chilean vaccination program really is in no way comparable to ours. I found an official Philippines web site that quotes the Sinovac dosing interval as 28 days so I assume that is the dosing interval that Chile is using hence even 6 weeks after first jab (again, inconsistency in article duly noted) an individual might have extremely modest protection.

The importance of Chile getting out the message to its population that they are not immediately protected as soon as they have had their first jab and should not let their guard down would seem to be even more critical than it is in the UK by quite a margin. In the UK the government has still tried quite hard to get that message out, I wonder how successful the Chilean government has been in getting a similar message out. Not very I would think since delivering such a message against a backdrop of "we can unlock now" really was not conducive to people remaining cautious so now they're having to lock back down again.

As long as the UK can keep variants such as the South African one down to a very low percentage of infections in the community for long enough for booster jabs to be rolled out then I don't think there are any Chilean mistakes that we are in danger of repeating although on the variants I would be more comfortable if the UK was doing 2 things differently right now. Firstly, putting in place more isolation support to fix what I see as the weakest link in the test/trace/isolate system that is going to be so important over the summer and autumn in keeping variants of concern down to low levels in the community and secondly (sort of related) I would rather the UK waited at least a bit longer than 17th May before opening up international travel too much.

- Julian

GrahamPlatt
Lemon Quarter
Posts: 2059
Joined: November 4th, 2016, 9:40 am
Has thanked: 1032 times
Been thanked: 823 times

Re: Can anything be learned from Chile?

#404591

Postby GrahamPlatt » April 15th, 2021, 7:17 pm

GrahamPlatt wrote:Rapid, point‐of‐care antigen and molecular‐based tests for diagnosis of SARS‐CoV‐2 infection

https://www.cochranelibrary.com/cdsr/do ... .pub2/full

"At 5% prevalence using data for the most sensitive assays in symptomatic people (SD Biosensor STANDARD Q and Abbott Panbio), positive predictive values (PPVs) of 84% to 90% mean that between 1 in 10 and 1 in 6 positive results will be a false positive, and between 1 in 4 and 1 in 8 cases will be missed. At 0.5% prevalence applying the same tests in asymptomatic people would result in PPVs of 11% to 28% meaning that between 7 in 10 and 9 in 10 positive results will be false positives, and between 1 in 2 and 1 in 3 cases will be missed."



As I was saying: https://www.theguardian.com/world/2021/ ... -positives

Though frankly, it’s not the false positives that worry me, rather the false negatives.

Lootman
The full Lemon
Posts: 18674
Joined: November 4th, 2016, 3:58 pm
Has thanked: 628 times
Been thanked: 6559 times

Re: Can anything be learned from Chile?

#404610

Postby Lootman » April 15th, 2021, 9:13 pm

GrahamPlatt wrote:it’s not the false positives that worry me, rather the false negatives.

Apart from the potential need to spend 2 weeks incarcerated in a 3-star hotel at great expense for no reason, of course.

GrahamPlatt
Lemon Quarter
Posts: 2059
Joined: November 4th, 2016, 9:40 am
Has thanked: 1032 times
Been thanked: 823 times

Re: Can anything be learned from Chile?

#404621

Postby GrahamPlatt » April 15th, 2021, 10:27 pm

Lootman wrote:
GrahamPlatt wrote:it’s not the false positives that worry me, rather the false negatives.

Apart from the potential need to spend 2 weeks incarcerated in a 3-star hotel at great expense for no reason, of course.


Here’s hoping you don’t find out how much a stay in ICU costs.

Lootman
The full Lemon
Posts: 18674
Joined: November 4th, 2016, 3:58 pm
Has thanked: 628 times
Been thanked: 6559 times

Re: Can anything be learned from Chile?

#404626

Postby Lootman » April 15th, 2021, 10:56 pm

GrahamPlatt wrote:
Lootman wrote:
GrahamPlatt wrote:it’s not the false positives that worry me, rather the false negatives.

Apart from the potential need to spend 2 weeks incarcerated in a 3-star hotel at great expense for no reason, of course.

Here’s hoping you don’t find out how much a stay in ICU costs.

You said FALSE positive, right?

GrahamPlatt
Lemon Quarter
Posts: 2059
Joined: November 4th, 2016, 9:40 am
Has thanked: 1032 times
Been thanked: 823 times

Re: Can anything be learned from Chile?

#404646

Postby GrahamPlatt » April 16th, 2021, 7:18 am

Indeed, but the false negatives will be the ones that cost people their lives.


Return to “Coronavirus Discussions”

Who is online

Users browsing this forum: No registered users and 2 guests