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Ruminator Dan

27 Oct, 11 tweets, 4 min read

ICL UK STUDY SHOWS DECLINING ANTIBODY LEVELS,
“DASHING HOPES OF HERD IMMUNITY”
ANALYSIS

An ICL led study of population antibody levels found that, between late June & late September “the number of people testing positive dropped by 26.5%”
imperial.ac.uk/news/207333/co…

[27 Oct 2020v1]

The interpretation reported in the media - & seemingly widely believed - is that only those with measurable antibody levels possess immunity & that, if those fade, people become susceptible to re-reinfection.
e.g. news.sky.com/story/coronavi…
& bbc.co.uk/news/health-54…

This ignores well established knowledge regarding the immune system, which is more complex than mere possession of measurable levels of antibodies. In fairness some articles do mention this.

However, the true judge is reality, which we can attempt to study through the data.

To begin, let's assume that the suggested hypothesis is correct:

Only those with measurable antibody levels possess immunity to SARS-CoV-2 & if antibodies fall below measurable levels a person is no longer immune.

...& then test the implications of this against reality.

Total UK cases around the end of June were ~280k & total deaths around ~40k, leaving ~240k total surviving cases.

We expect ~64k (26.5%) of these people to have lost immunity by late September & a good many more by late October. This is around ~0.1% of the entire population.

(We are ignoring, for simplicity, cases recorded after June, which would make this number larger).

Currently (late Oct 2020) reported new cases per day are ~20k. Given the above, one would expect ~0.1% of these to be re-infections of people previously infected in the spring. That is equivalent to ~20 people per day.

Where are they?

Given the general interest & the huge amount of work being done, it is highly unlikely that such re-infection instances would escape notice & publicity.

Yet, to the best of my knowledge, there have been only a handful of re-infection cases recorded worldwide.

Our hypothesis regarding antibodies does not match observed reality & so is incorrect.
This is important as it seems a widely held belief.

Lack of re-infections would suggest/confirm that there is more to immunity from SARS-CoV-2 than possession of measurable antibody levels.

[Analysis, opinions and errors my own.]

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Ruminator Dan

@RuminatorDan

22 Oct

CZECH REPUBLIC & HUNGARY
are currently reporting higher daily Covid-19 deaths per M than other European countries. Current daily deaths are significantly higher than their spring peaks. Interestingly, both experienced far lower earlier total deaths than many other countries.

One possibility is that the lower earlier totals correspond to fewer infections, leaving a larger proportion of the population still susceptible.

Incidentally, I do agree with people who've pointed out the unpleasantness of treating this sort of comparison almost as a macabre spectator sport. That should not be the intention. The purpose is to use the information to learn about the virus, value of measures taken etc.

Read 4 tweets

Ruminator Dan

@RuminatorDan

14 Oct

AUTUMN 2020 CORONAVIRUS GROWTH
IN UK, FRANCE, ITALY & SPAIN
APPEARS TO BE MUCH MILDER THAN SPRING

An analysis:

[14 Oct 2020 v1]
[Notes added to charts in grey bubbles are my own.]
[Analysis, opinions & errors my own.]

Several countries that experienced relatively high fatalities in the spring have seen an autumn increase. The patterns are similar.

Comparing the recent increases to the spring suggests that the underlying situation might be significantly less severe than generally believed.

TESTING: See notes on chart.

Despite numerous issues relating to testing, we will treat the data as accurate here so as to err on the side of caution & good faith. This should give us a worst case picture, with the reality being likely somewhat milder.

Read 10 tweets

Ruminator Dan

@RuminatorDan

5 Oct

An estimated 750M, 10% of world’s population have been infected by Covid-19, says WHO's Dr M Ryan

This implies far lower Infection Fatality Rate than previously claimed & potentially significant implications for many countries.

Analysis:

[5Oct2020_1]

irishtimes.com/news/ireland/i…

While clearly this is only a "best guess" figure, we can still conduct a rough analysis, leading to an interesting conclusion.

10% of world population ~ 750M
Covid-19 deaths to date ~ 1M
Implied IFR = 1/750 = ~ 0.13%
(IFR = Infection Fatality Rate)

An IFR of ~0.13% is almost an order of magnitude lower than the ~1% values seen in much of the predictive modelling that has been used to guide policy, lockdown decisions etc. (E.g. ICL used 0.9% for UK in March).

Even for a rough estimate, this is a significant difference.

Read 10 tweets

Ruminator Dan

@RuminatorDan

26 Sep

ANALYSIS OF SARS-CoV-2 GROWTH ILLUSTRATION PRESENTED AT VALLANCE-WHITTY DOWNING STREET BRIEFING ON 21 SEP 2020

Implied CFR appears to be >50% lower than IFR used by ICL in March, suggesting new cases in red area would lead to ~2,000 deaths (~5% of spring total).

[26 Sep 2020v1]

The red area would contain a total of ~500,000 new cases.

How many deaths would be expected to occur as a result?

PV commented that, by mid October, there might be 50,000 new cases per day & that this would be expected to lead, a month or so later, to 200 plus deaths per day.

This implies a Case Fatality Rate of approx:
CFR = 200 / 50,000 = ~ 0.4%.

Since not all infections are detected, the Infection Fatality Rate (IFR) will be lower still.

This ~0.4% CFR is, however, in itself 50%+ lower than the 0.9% IFR used in ICL’s March paper & modelling.

Read 6 tweets

Ruminator Dan

@RuminatorDan

24 Sep

SEP 2020 CORONAVIRUS CASES INCREASES
IN UK, FRANCE, ITALY, SPAIN
APPEAR DIFFERENT FROM SPRING

The UK, along with other European countries, is experiencing a rise in SARS-CoV-2 cases.

[24 September 2020, v1.1]
[Analysis, opinions & errors my own.]

Many think this to be a similar situation to that experienced in the spring. However, there are also reasons to suspect that this might not be the case.

Here, an analysis using testing, cases and deaths data:

TESTING:

Testing has increased enormously. In spring mainly the ill were tested & the quantity of tests was far lower. In terms of true numbers of infections, we were only detecting the tip of the iceberg. Today, we conduct mass testing of the healthy.

Read 14 tweets

Ruminator Dan

@RuminatorDan

23 Sep

https://twitter.com/JamesTodaroMD/status/1308831837263982594

Faucci & recent UK comments disagree with recent evidence re low HE threshold/pre existing immunity etc. However, even without knowing the underlying mechanism, the observed reality (data) strongly suggests it. Sweden, e.g., is prime evidence. Note also how those locations 1/4

https://twitter.com/JamesTodaroMD/status/1308831837263982594

https://twitter.com/RuminatorDan/status/1299096163606556672?s=19

in which the virus appears to have run its course have fairly similar outcomes. The differences between fatalities in these locations are small compared to the fact that they are all about a tenth of what was predicted. This is meaningful information. 2/4

https://twitter.com/RuminatorDan/status/1299096163606556672?s=19

If the "high fatality & all susceptible & lockdowns worked" scenario was true for these locations, one would expect more variance between them than we see, because outcomes would be highly sensitive to the measures taken & their timing (as Neil F himself has, I believe said) 3/4

Read 4 tweets

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