UKH

Worldwide the number of deaths per infection are currently around a quarter of what they were back in April,  In the U.S the death rate is around 1/6 of what it was in april.

So how is this possible.

Is it because increased testing is just making us more aware of true number of infections?  This seems unlikely because even in very poor countries where testing is minimal the death rate is now much lower. 

Is it that despite there being no single effective treatment(remdesivir and dexamethasone only save a few percent), cumulatively all the new treatment techniques together are making a massive difference?

Is it because Covid has mutated and there is now a less deadly strain in circulation? Let's hope so! but I haven't seen any reports suggesting this.

Is it because large numbers have already developed t-cell immunity and so are now not susceptible? seems unlikely because you would think this would also reduce the number of new infections.

none of these answers seem capable of explaining a six fold decline in deaths, so what other ideas do people have?

Question the evidence.

Is there solid evidence that the death rate has fallen six fold?

In reply to climbercool:

Weaker strains might be spread faster 

All the most vulnerable have already died

More testing, thus more cases being found

I agree, there is lots of reporting of new cases, but i don't know if hospitalization and death rates are correlating. 

In reply to climbercool:

It's because we're all wearing masks at the supermarket now.

Oh wait we haven't started yet...nevermind.

In reply to climbercool:

All of your things are possible.

Also, in some countries there is significant scepticism about the reported death rates.

And the other factor is that many of the countries now being hit by the pandemic (obviously excluding the US) are developing nations with lower average ages and fewer co morbidities, which will significantly reduce the death rate from Covid. Whereas in some parts of Europe, old people in care homes were disproportionately infected and are also most likely to die.

In reply to climbercool:

I know the vitamin D link wasn't entirely proven, but it could be that fewer people are vitamin D deficient at this time of year? 

It is probably a cumulative effect of several factors

In reply to Si dH:

And getting better at keeping outbreaks out of care homes in European countries. Something the UK seemed to struggle with despite spending vast sums on nightingale/enfys hospitals and then not using them!!

In reply to climbercool:

Also to consider

• Testing has scales up
• The corticosteroid trial - improves chance of not dying
• Learning about when not to ventilate but to use CPAP meaning more ITU survivors
• Reduced viral load reducing severity of infections???

In reply to climbercool: All the above.  Also, in the US, outside New York so far they've just about managed to cope in terms of hospital capacity although alarm bells are ringing like crazy re. that.  

summer helps a lot

In reply to climbercool:

It's probably a bit of most of those.

Testing has opened up to those who aren't acutely ill and in some cases, for screening those who aren't ill at all therefore given it seems most cases are mild to fully asymptomatic more of the cases found will be survivable.

Treatment will be improving even if only subtly. One morbid (though fairly unlikely) prospect is that may simply be delaying covid deaths longer skewing the stats temporarily without changing the long run numbers.

The most susceptible in some settings will have already had it building some immunity and in some cases they will have already died.

We're getting better at keeping it out of high risk settings for a number of reasons: more available PPE, better training and planning, better isolation of identified cases, fewer staff issues (sickness and isolation at peak).

People who are at risk know it and have a good idea where the virus is, where it probably isn't and how to stay safe.

We're well out of seasonal flu season, fewer patients will be presenting with multiple simultaneous life threatening infections.

It's possible the virus has got milder but it's not necessary to explain what we see. Given there's little evolutionary pressure, it spreads freely as is and it's still very new I have my doubts. It's not like it's killing its hosts before we can spread it around.

Mostly I suspect it's the shift in who's getting it, out of care homes and back into the healthier working age population resulting in decreasing severity of the cases we do identify due to who qualifies for and takes tests.

jk

In reply to climbercool:

I would largely agree with jkarran's post above. The reduction is likely down to a combination of many effects.

The most important ones are likely to be:

- The difference in testing numbers and the availability of who gets tested. At the beginning, people were dying in large numbers without ever getting tested. Now, even the most mild cases have a good chance of being tested.

- It was initially spreading like wildfire through our care homes and hospitals so the most vulnerable were catching it leading to a higher proportion of severe cases.

- More ominously, seasonal variations may now be temporarily helping reduce the severity of cases and the piece of transmission. If this is the case and turns out to be a major factor, the feared second spike is likely to occur in the autumn. https://covid.joinzoe.com/post/weather-covid

Improved treatment will have had a part to play but I don't think we have evidence that it has played a big part.

I suspect we are currently underestimating the immunity in the population but who knows whether that will continue long term.

I haven't seen any evidence to suggest that we have been helped by any mutations and that idea doesn't seem to be supported if you compare the virus' progress across the world. There are certainly a lot of unknowns though and I don't think our understanding can explain all of the variation in spread or severity so I can't rule out it playing a part.

In reply to SDM:

Spreading like wildfire through hospitals? Was it?

In reply to Rob Parsons:

Yes it was.

https://www.telegraph.co.uk/news/2020/06/20/forget-doom-gloom-retreat-covid...

https://www.spectator.co.uk/article/we-know-everything-and-nothing-about-co...

In reply to climbercool:

Entirely down to more testing and the target test demographic.

In March we had less than 10,000 tests a day. Vs 1000+ deaths. Not all were positive but assuming they were because we were testing mainly hospital cases, that’s about a 10% death rate. 
Then we had 100,000 tests a day and were testing many more people, even those in the community with mild cases showing symptoms and in some cases no symptoms.

Although we were seeing less cases, those cases we were seeing were from people who wouldn’t previously have been tested because they were mild cases. 

In reply to climbercool:

Because we're better at keeping people alive now, we know more about it.

and there's less pressure on the NHS so patients can be more closely monitored.

Plus a host of other reasons most people have posted above.

In reply to climbercool:

Testing.

Case numbers are now the limiting factor, not testing capacity. We now have the capacity to test anyone who asks for it, or who has a cough or sniffle. So we are discovering many more mild infections than we did when testing capacity could not keep up with demand, and even those quite severely ill were not being tested.

Testing has probably always been the dominant differentiator between international infection:fatality rates 

In reply to SDM:

It's not impossible that the next flu season will see less flu deaths, as in blunt terms any one remotely vulnerable has been killed by covid already. 

Some places are reporting lower than average deaths for the time of year. This could be down to improved hygiene, folk aren't taking normal flu viruses into care homes etc.. or the fact they all died in mar, apr and may. 

In reply to climbercool:

This paper just shared by the Kings College COVID 19 symptom tracker study/app indicates the significance of humidity and temperature on Mortality ...somewhat alarming 15% decrease in mortality for each +ve degree Celsius in ambient temperature. Given between march and July we are looking at around 12C thats quite an impact. 
https://www.medrxiv.org/content/10.1101/2020.07.11.20147157v2
(the paper is submitted for rapid peer review)

Some of the other findings are interesting re: low indoor humidty reduces the ability of the body to maintain a mucosal protection against viral load. Probably makes Climbing walls cold and dry favourable environments for COVID 19. Overall none of it bodes well for the winter. 

In reply to summo:

I think that is very wishful thinking considering 1.5m (?) extremely vunerable people have been shielding and there are still hundreds of thousands in care homes....

In reply to climbercool:

Another global issue:  given age and weight are two key factors, countries with lower standard mortality rate and lower obesity problems will have lower death rates (i.e. many developing countries may suffer less than countries with older, more overweight people).

In reply to simondgee:

 

Depends on the wall really. Since several of the London ones rapidly resemble a steam bath in summer sounds like they are sorted. Turn the fans off and shut the ventilation and carry on.

In reply to Blunderbuss:

I tend to agree with summo, another reason being people vulnerable to flu are now more likely to take covid precautions thus reducing the chance of catching flu.  Also, whereas people with none covid colds/coughs/flu/sniffles simply carried on life as normal, an increasing number will take time off sick and do a version of self isolating. I think more people will get the flu jab than ever before (i'm eligible but never bothered until now).

In reply to mick taylor:

I agree with all that, just not his idea that COVID has already killed off most of those that were vunerable...