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New Coronavirus

BoJoke (20 posts) • 0

lemon, madly in love with state media Chinadaily news aren't you? The tricky part is that by the end of February, "43,000 people in China had tested positive for COVID-19 without immediate symptoms" according to above SCMP article. Three studies below show why rounding up asymptomatic carriers for quarantine may be challenging as lockdowns are being lifted:

1. This study details the "case of an infected individual who never developed symptoms but shed a similar amount of virus to those who did."

www.nejm.org/doi/10.1056/NEJMc2001737

2. This study suggests "there were 37,400 people with the virus in Wuhan who authorities did not know about, and who had mild or no symptoms but could still be contagious."

doi.org/10.1101/2020.03.03.20030593

3. This study "showed people had high levels of the virus in throat swabs early in their illness, when their symptoms were mild, meaning the disease could easily be spread through coughs or sneezes."

www.medrxiv.org/content/10.1101/2020.03.05.20030502v1

Source: World Economic Forum
www.weforum.org/[...]

lemon lover (878 posts) • +1

Well Bojo I am just passing on information. By referring to state media I know how to judge this information namely that it is the government’s version of the truth.

Asymptomatic Covid-19 infected persons are only found because they are tested to start with. This testing was done because they were in close contact with a person who was tested because they showed symptoms. The trigger for the test and their discovery is thus related to somebody with symptoms.

The near zero discovery of home grown positive cases at this moment shows that asymptomatic cases don’t spread the disease in significant numbers. And are therefore luckily insignificant in the whole picture.

I quote from one of your linked to articles: “A new study suggests there were 37,400 people with the virus in Wuhan who authorities did not know about, and who had mild or no symptoms but could still be contagious.”

Note the words “COULD still be”. Well with Wuhan now already for days being new cases free this indicates that they are not.

Now that more tests are available I think it is a good thing that people coming into the country are tested (And spend time in preventive quarantine).

At this moment there are only two countries that managed to flat-line the curve, China because of rigorous measures and South Korea because of large scale testing. This large scale testing discovers asymptomatic cases as well but again apparently they have a near zero RO number. Still the positive tests of asymptomatic cases are useful because it improves (self) isolation of these cases which they might have more lax with if they were tested negative.

Personally I think test positive cases should be included in the total positive case number.

JanJal (1027 posts) • 0

What do you people think, or have read about, natural resistance that might be developed among populations for this virus?

Specifically I'm thinking that in certain (mainly western) countries the policies seem to reflect assumptation that that it's here to stay, and their main goal is to slow the infection rate within their borders so that their healthcare system can answer to the demand of serious cases.

Unlike countries like China where the healthcare system was probably never going to be up to the task, and therefore completely stopping the spread was considered a necessity.

Given this difference between countries, will some populations in general have better natural resistance in coming years, while in other countries more people will suffer also in future seasons unless prevented with vaccinations among general population.

lemon lover (878 posts) • 0

Janjal the answer on your question is not easy because one has to understand the underplaying reasoning of various governments. In general China thinks it still can manage society while in most western countries they have realised that they cannot and therefore concluded that they have to accept that Covid-19 is here to stay. There are countless examples of the failure of social distancing that failed in the western world while in China it largely did work. China as well had a track record of, at the end, stamping out SARS, and the lessons learned from that were put in to practise now. Few other countries took serious lessons from that.

Different to European counties, China had as well the spare capacity to draw from a fast country to deal with what in the end was basically a regional problem.

There are three ways to overcome Covid-19 : Number 1, and the best, is a working vaccine. Two and three are an effective medical cure and heard immunity. China believes that by applying effective control measures it will buy enough time to develop a vaccine. Given the emergency they don’t have any problem with fast tracking vaccine development. In western countries this is more problematic because of medical standards and ethics.

Trump thinks a miracle cure is possible and puts all his hopes on new and old medicines. In Europe this is considered wishful thinking.

Given the timeframe for these different scenarios some European countries realised that they didn’t have any other option then to go for heard immunity. Not because it is the best but because it is the only realistic option. One has to realise that these countries have very open societies and in practise open borders.

In my work, already a long time ago, I learned that with epidemics it is not the disease that is the problem but the collapse of the health system and the possibility of total panic. The disease is a given fact and you deal with it. Panic and collapse are much harder to deal with (and have grave consequences for the powers that be).

The main thing during an epidemic event is to flatten the curve till a level that the healthcare system and other parts of society can deal with. In China they managed to do this and South Korea is nearly there. Taking half and insufficient measures let to the situation we have now in most of the western world. I know of only one western country that had the guts to take the right measure in time and that is New Zealand (But they had plenty of time to see other countries fail.).

At the end it will be heard immunity that is created by a fast group of recovered patients and by those vaccinated that will get this disease at manageable levels like for instance the flu.

Manageable levels, by the way is what society thinks it is. Every year there are 1.5 million people dying of tuberculoses and “we” think that’s acceptable. For tuberculoses, which has been around since humans started to walk on two legs, never a vaccine was found and medical cures turn out to be only limited in their effectiveness.

Trumpster (83 posts) • 0

A couple thoughts.

1) Herd immunity only works if the virus does not mutate, which is why flu shots are required every year and why there are no vaccines for the common cold.

2) SARS-CoV-2 is to Covid-19 as HIV is to AIDS. Being infected with a virus is not the same as having the disease. There could be a significant lag between getting infected and developing the disease (as is the case with HIV and AIDS) or getting infected and not developing the disease (as is the case in Hepatitis carriers). So depending on the specific nature of the virus/disease, you might only track one but not the other.

3) Its easier to be an armchair general than to be at the front lines making the tough decisions. Thus far, no country has been "perfect" in their response and it would seem Trump is guilty of the many things Pompeo is blaming China for.

4) There is always a cost associated with any government policy/decision that is rarely discussed. It is undisputed that whether it is forced quarantine, volunteer social distancing, or shelter-in-place orders, there is an economic cost for society to shoulder, actuarians can workout how many extra deaths will result from such burdens. In essence, saving X number of people will cost Y number to die from the measure. Quite an ethical conundrum even if X is vastly greater than Y.

BoJoke (20 posts) • 0

lemon wrote, "Personally I think test positive cases should be included in the total positive case number."

So we both agree that citizens who've contracted the virus and have tested positive, should be included in the official tally despite showing no symptoms of illness.

As mentioned above, tens of thousands of patients WERE tested positive for Covid-19 but were intentionally left out from reporting. If these positive test result cases are unaccounted for at present and in foreseeable future, how can we definitively pronounce "near zero discovery of home grown positive cases?" Or proclaim "Wuhan now already for days being new cases free?"

How can we accurately access "flat-line of curve" if we discount these empirical data with the knowledge that positive carriers who do not show symptoms may still harbor low viral load? As above-posted study pointed out, "an infected individual who never developed symptoms but shed a similar amount of virus to those who did." Meaning, they can still possibly infect others without showing symptoms.

You also mentioned that "testing was done because they were in close contact with a person who was tested because they showed symptoms."

I argue contact tracing may become more challenging as lockdowns are lifted, such as in Wuhan. Undetected asymptomatic carriers are now free to roam outside their two-month containment zones of near proximity traceable clusters. Yet now, movements to transport hubs en route to other cities and provinces compound the difficulties of contact tracing as conducted previously during stringent lockdown. To say nothing of testing/reporting transparency of migrant workers in rural versus urban China.

That is my main concern with discrepancy of reporting standards (and rates estimations) in light of economic normalcy of 1.4 billion free flowing movements.

DanDare (64 posts) • 0

Some amateur attempt at analyzing raw numbers is pointless, it only serves the needs of the merchants of doubt, or the fear mongers. Every country, including China, has publicly recognized that the numbers given are not a complete count. Every expert has said that the actual numbers are many times higher than the data captured.

The people diagnosed are only a sample of the whole population. No sample is ever perfect, or fully represents the situation.
As knowledge increases it will be seen that people have been missed out of sample data, but by constantly changing what is being included in the sample will blur the data and make seeing the trend much more difficult. If you keep putting things into/out of the raw data, it will not be possible to easily see if the curve is being flattened, i.e. are the measures taken having an effect.
Fear not the new data will be input to the epidemiological models, and these models will more complex than I am able to comprehend. I have see no need to explore them.

lemon lover (878 posts) • 0

Bojo you miss the point. The point is that apparently the RO number of these asymptomatic carriers is near if not zero. We know this because no more symptomatic cases develop.

For days now the daily change of the total number of infected cases is equal to the number of imported cases meaning that there is no detectable spread of home-grown cases. Be happy with that instead of trying to find your zombie spreaders.

I know that medical data is often polished up for all kind of reasons but you can look at things is various ways: you can state that asymptomatic positive people are not part of the caseload because they are not ill (And form no danger because they do not spread). We only know of these cases because they were tested. We do not know how many people carry the virus because they were not tested. Including only the tested asymptomatic cases gives us therefore not the total number of people who got the virus and therefore it is still not a useful number.

The Chinese authorities chose to tally the total number as the people who got sick. This actually is a useful number.

Finding the total number of people that picked up the virus can only be done with a large scale study testing for antibodies. A lot of work and that number might not even be relevant in the bigger picture.

Mind you I am not saying the problem is over. It still can relapse. But this is more likely to come now from imported cases and home-grown not discovered yet cases.

DanDare (64 posts) • 0

Zombie apocalypse lol. If people are only looking for conspiracies, that is all they will see. Rational explanations are a waste of time, you might as well be Dr Fauci talking to the orange one.

faohi421 (10 posts) • 0

Lemon, disagree.

You may want to read up on a recent study coming out of the hardest hit region in Northern Italy claiming that Covid19 carriers with no symptoms could spread disease:

"Analysis of patients in Lombardy region shows similar viral load, regardless of symptom severity..."

'“We did not observe significantly different viral loads in nasal swabs between symptomatic and asymptomatic subjects, suggesting the same potential for transmitting the virus,” the paper said."'

"The Italian research paper, available on preprint journal platform arXiv, was based on an analysis of 5,830 laboratory-confirmed cases between January 14 and March 8. Half of the cases studied were under the age of 50."

www.scmp.com/[...]

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