Covid-19 and purity spirals

And it only took a global pandemic to sort it out.

many genes that regulate the immune system are encoded on the X chromosome (of which men have one, and women have two)

A few weeks ago that would have sent the TRAs into spasms. The Guardian would never have got away with it.

It's funny how they know what a man/woman actually is in this context isn't it?

The Guardian once again dispensing with gender essence nonsense to talk about biological sex.

Men are much more likely to die from coronavirus - but why?

www.theguardian.com/world/2020/mar/26/men-are-much-more-likely-to-die-from-coronavirus-but-why

There might also be a crossover period where both tests could be negative depending on sensitivity

There’s quite a good study talking about the sensitivity/specificity and time to become positive for the various antibody tests in SARS (with implications for COVID-19) and my brief impression was that the testing would miss a chunk of true positives. I’ll look for it, but not now. It’s night time here

Mixed reviews of the study.

www.sciencemediacentre.org/expert-reaction-to-unpublished-preliminary-findings-looking-at-the-presence-of-antibodies-to-sars-cov-2-virus-in-residents-of-gangelt-in-germany/

www-technologyreview-com.cdn.ampproject.org/v/s/www.technologyreview.com/2020/04/09/999015/blood-tests-show-15-of-people-are-now-immune-to-covid-19-in-one-town-in-germany/amp/?

That's what I was saying re the studies NoLongerSurprised - I've not seen that info re the German study.

There might also be a crossover period where both tests could be negative depending on sensitivity

The German study does suggest relatively low immunity, although it is very hard to compare across populations, from small towns to big cities, and so on.

Even 15% already having had it would be good though IMO - it would mean the death rate is much lower than thought, and it would also reduce (not remove, but reduce) the ability of the disease to spread in future waves. I'd also expect that immunity to be concentrated, so NHS staff and other keyworkers are more likely to have had contact with it and may have much higher levels of immunity which is good from a maintaining healthcare perspective.

Going by the German study though only 15% of the population in a hard hit town have had it. Bearing in mind 60 - 70% is needed for herd immunity I don't think infection rate is high amongst the population.

If the German study just looked for IgG antibodies though, there’s likely an underestimate. The presumption seems to be it’ll take two weeks to build an IgG response (based on SARS tests) whereas IgM and IgA will be present earlier. If IgM and IgG are tested for the numbers will be higher..

Going by the German study though only 15% of the population in a hard hit town have had it. Bearing in mind 60 - 70% is needed for herd immunity I don't think infection rate is high amongst the population.

If only 15% have had it in an area that was badly hit then it stands to reason in a less affected area the rate will be much lower.

In the UK for example, maybe we'll see rates of 15% in London but under 10% in other parts of the country. Chris Whitty estimated single digits in the press conference the other day didn't he?

I don't see these figures as reassuring at all because it seems like there will still be huge numbers of people vulnerable not catching it when lockdown is lifted, so how will they avoid overwhelming the NHS again and again?

Recent research (reported in a few places) suggesting the r0 might be a lot higher than originally thought, possibly 2-3 times the previous base estimate

Which is both good and bad, presumably? It means that there’s probably higher baseline immunity in places with community spread (good) but containment is much less likely, if possible, once it’s taken hold.

It's certainly very much needed; the level of discrepancy in the possible cases is a huge problem.

The r0 could be significantly higher than first thought - which in turn means the current r0 is probably higher than estimated since it was basically a scaled down version of the original, but also that the number infected (currently or historically) is probably much higher.

The proportion of people who are totally asymptomatic is being reported within a massive range (I've seen 15-70% I think!)

The proportion with minor symptoms which are being missed - either not even suspected as covid but as a cold/hayfever etc, or which are suspected but not tested (everyone I know who has likely had it is in this category!)

The deaths which are being missed (community/care homes)

All of this means the death rates and intervention rates could be out by a very significant amount - in the UK the reported death rate could be anything from accurate (unlikely) to about 50x too high (we can hope).

In a way it would be a good thing if it transpired many more have had it than thought.

This is standard practice, everywhere. It’s what ICUs do. Sounds like he wanted his 15 minutes of fame.

Oh I give up. Yes, I know. I was making the point that he wasn't just saying "tidal volume low, PEEP high". He was giving parameters and adjustments that he recommends based on specific values. I am trying to summarise what he said, not giving an in depth report. But, whatever.

This is sobering reading for anyone advocating a rush out of lockdown

m.huffingtonpost.co.uk/entry/coronavirus-nightingale-hospital-ventilator-covid_uk_5e9061b3c5b6319d8db64376?guccounter=1&guce_referrer=aHR0cHM6Ly93d3cudGhlZ3VhcmRpYW4uY29tL3VrLW5ld3MvbGl2ZS8yMDIwL2Fwci8xMy9jb3JvbmF2aXJ1cy11ay1saXZlLW5ld3MtcHJhaXNlLW5ocy1udXJzZXMtcHJpbWUtbWluaXN0ZXItYm9yaXMtam9obnNvbi1sYXRlc3QtdXBkYXRlcw&guce_referrer_sig=AQAAANRFAaoDO-ZvKglrFVCpywRh3rvNChBvg_kkMnYHHdym6VY2u-almp_EFyag2kvlDftw9SpivnY6KDCZKc-DYsn2sGNXgB_W7bvESpLcxARDzDzbIWWKh230b3PyVNhbnp6CdgkUGnseM_4wcC8Ex4gDzyFi0f60E0KZf0FqMUm7

He was also talking about titrating it to arterial blood gases too and so the ventilator settings were very dependent on those readings.

This is standard practice, everywhere. It’s what ICUs do. Sounds like he wanted his 15 minutes of fame.

I hadn't seen that re Porton Down - I thought they were still trying to evaluate the antibody tests. I'd hope they're doing both tests though given it's likely to take several weeks to show antibodies (and for at least some of that you'd still be testing positive)

They already have a lab antibody test because they've tested in a town in Germany and another in Italy. I think the test they are trying to develop is a bedside antibody test. That's the one causing problems.

I don't know the full details of the Porton Down study other than its 800 random samples to determine the prevalence in the community.

His view was to keep tidal volume as low and then to increase PEEP ( with certain parameters) but he ran through many different adjustments depending on results. His view was that many drs were increasing tidal volume in an attempt to improve oxygenation but this was actually causing damage to the lungs and that it was better to accept a lower oxygen level.

I didn't realise that I was presenting a clinical paper and assumed talking about tidal volumes and PEEP in s non clinical setting probably would not mean much to many people.

He was also talking about titrating it to arterial blood gases too and so the ventilator settings were very dependent on those readings.

There does seem to be some very contradictory info coming out re vent use which is really unhelpful for the public as it will reduce their trust in receiving the right healthcare.

I hadn't seen that re Porton Down - I thought they were still trying to evaluate the antibody tests. I'd hope they're doing both tests though given it's likely to take several weeks to show antibodies (and for at least some of that you'd still be testing positive)

As above, the study concurs with his findings so not sure why you are being quite so aggressive really.

The study says that higher PEEP is required though. It’s not clear from your post whether he was talking about PEEP or tidal volume, just referring to “pressures” isn’t helpful.

Then he needs to raise it with his peers, bang out a quick observational study and be transparent about his outcomes. Not look for his 15 minutes of fame with Joe Public.

As above, the study concurs with his findings so not sure why you are being quite so aggressive really.

nolongersurprised

Those guidelines are very interesting and do indeed back up the American Dr that I quoted in regards ventilator pressures.

Interestingly they also highly recommended oxygen therapy when sats are 90% or lower which is clearly not happening in the UK

If what he believes is true, then that has massive implications for the treatment of this

Then he needs to raise it with his peers, bang out a quick observational study and be transparent about his outcomes. Not look for his 15 minutes of fame with Joe Public.

The guidelines for critical care medics from that JAMA consensus paper wasn’t just created by Americans either (in spite of being published by JAMA).

It was authored by 36 experts from 12 countries and supported by the European Society of Intensive Care Medicine and the Society of Critical Care Medicine, with the latter a group of critical care specialists from many countries.

Because paramedics are coming out, testing sats and then refusing to take them in, with sats in the low 90s and because 111 are refusing even to send an ambulance unless the patient is cyanotic ( which means sats in the 80s usually, or lower) or until they can't speak.

As for over ventilation, I'm not sure what you mean. Do you mean we aren't ventilating too many people? Maybe we aren't, but maybe the ones that we are are much sicker when they are eventually ventilated and had they received earlier oxygen therapy they wouldn't have needed a ventilator.

My comment about the American doctor is about the settings of the ventilator. That the drs are making mistakes and in doing so are irreparably damaging the lungs and meaning that the gaseous exchange function cannot happen. If what he believes is true, then that has massive implications for the treatment of this. That lower pressure ventilation, even if that means oxygen sats aren't in the high 90s for a time, is preferable.

This is such a new disease and drs are feeling their way through. I just hope that lots of good quality research is happening, and that results are available and shared quickly so that best practice guidelines are published as soon as possible.

I very much doubt the NHS is over ventilating. Remember of course that we have less ventilators than the big private hospitals in America (and are less likely to sue for them not throwing every treatment at the patient) so I expect the threshold to ventilate someone here will be higher.

I don’t understand how patients phoning 111 are being refused help ” being refused help because oxygen saturation isnt in the 80s” How do they know?

Once they have a reliable one then it would useful to get random sample testing done to try and get a better understanding of the true level of infection in the population - probably giving everyone in the sample both antigen and antibody tests

They've done this. 800 random samples being tested for antibodies at Porton Down