Something doesn't add up to me

[Greysparkles]

If the virus is as contagious as claimed by some, as in you'll catch it from sitting on the same patch of grass someone else has, or just walking through where someone sneezed earlier.

Why haven't more of us got it??

That certainly weakens the survey - if it's based on volunteers you will inevitably get people who suspect infection selecting at a greater proportion than those who don't. So you end up with a disproportionately positive sample compared to population

Excluding confirmed positives from the random sample then biases the asymptomatic percentage upwards.

They might have controlled for such things though. It would still be very interesting to see them follow through for the typical lifecycle to understand how many asymptomatic remain so.

On the flip side, what's your quarantine requirements? If it's like here then you'd be missing positives - symptomatic people and their households

Designing studies like these well is not easy

but then why didn't the umber of cases go up much faster from January? it was mid-March when we had the first recorded deaths in the UK. If covid-19 was really here from mid-January you'd expect it to have started spreading then, not waited until March...

@tenlittlecygnets - It was mid-March when we had the first recorded deaths. It is very very common for older people or people with serious illnesses to die of pneumonia. There will have been deaths that just looked like an expected outcome of the person's age or illness in which covid played a part.

Again it's about sheer numbers combined with knowledge. So a death here and there from pneumonia, even among younger people, will raise no alarm. It's sad but it's no especially unusual. Then news comes of the virus and people start noticing these deaths more but there isn't a test so there's no way to know what the real cause is. Meanwhile the virus is spreading and spreading and reaching a greater number of more vulnerable people. Combine testing with that spread and bam! it looks like a huge jump all in one go, when in fact that build up was much slower.

Remember that if the doctors in Wuhan hadn't raised the alarm we might be reading in the papers about a weird flu and thinking very little of it. Health systems are actually quite bad at spotting patterns of illness at the time they are happening - we only know about the covid patterns because we were warned about them and we're actively tracking them.

One thing is definite about the official statistics around infections and deaths and that is that they are entirely skewed and unreliable. For every person in a care home who dies from it there will be a care worker who's brought it to them and the care worker's family, all of whom may have few or no symptoms and won't appear in the statistics. Equally there will be thousands of other mild/moderate cases that are never recorded.

Residents entering the country quarantine for 2 weeks.

If you've been identified through contact tracing as likely to have been exposed, you quarantine for 2 weeks.

If you have likely symptoms (fever, cough, aches) you are supposed to quarantine yourself and call the healthline and they will test you if they suspect you have it.

Once you're confirmed then you have to isolate, which is stricter than quarantine.

I think that what they were always trying to do is find out how widespread the virus was among people who weren't exhibiting serious symptoms. Because some of the cruise ship data suggested that large numbers of people could be walking around with the virus and never show any symptoms. But that doesn't seem to be the case in Iceland anyway.

In that case it's a miracle they got 50% symptomatic! It looks like they were specifically testing people with no symptoms...

There do seem to be a fair few studies showing relatively high asymptomatic levels.

Such a big uncertainty that makes a massive difference to the correct way to handle this. If there are truly 50% asymptomatic and the stats found in those countries testing more extensively are correct (some finding death rates well under 1% of diagnosed cases which would be even lower if you factor in asymptomatic and therefore likely undiagnosed)

There's a vast difference in how you handle a disease with, say, 20% hospital admission, 5% ICU, 2.5% death compared to one which is actually 4% admission, 1% icu, 0.5% death (I'm assuming the ratios between admission/icu/death are consistent)

It looks like they were specifically testing people with no symptoms...

Exactly, that is how I understood it as well. The quote that all the foreign media reports are based on said that the other 50% had 'mild cold symptoms'. It's been taken wildly out of context.

Apparently over the next few days they are prioritising people of foreign origin so I might pop along myself!