We’re finally getting some results on this. An antibody test in an Italian town an hour outside Milan has been done. 2000 people out of a population of 6169 have been tested.
Results: 13-14% of the population tested positive for the antibodies (~832 people).
The town had 27 confirmed cases, with 4 confirmed deaths. 6 deaths of all causes were recorded in March.
So this is arguably good news. It implies an IFR of about .5%. If the population here is older/unhealthier than average, as seems to be true for Northern Italy as a whole, then we could see that number dipping down further. Covid being less than an order of magnitude worse than the flu is starting to look likely but there is still a long way to go to reach herd immunity and I personally think that they should at least try for actual suppression unless we get really good numbers on the death rate and are more confident that survivors won’t have lasting side effects.
Someone in that twitter thread points out that with subtracting false positives, it implies that 10% would be the better guess, as opposed to 13-14%. Does that make sense? Then 4 Covid-confirmed deaths per 620 people would be 0.66%.
And what about sampling bias? I read that the tests were voluntary. Unless someone was extremely meticulous about trying to somehow get a representative sample, I don’t think it’s reasonable to treat this as random. It’s really quite obvious that people who had flu-like symptoms for a couple of days will be more curious to go among people and have a needle stuck into them. .
I share your rough estimates of IFR in your other comment here although I was concerned about how high IFR might be with overwhelmed hospitals.
Sampling bias at its worst here would mean that IFR is 3 times more than those calculations (i.e. 1.5-2%). If this is the worst case in Lombardy where the hospitals are overwhelmed then it is something of a relief to me that higher rates are unlikely.
Very interesting, thanks. I think it’s 13% of tests, not 13% of entire population of 6′169, so not 832.
I don’t speak Italian and struggle to find any details. Actually they didn’t mention that all 2′000 samples were processed. On 5th April the mayor of the town posted a photo of newspaper mentioning “29% of 38 persons” positive. So I would not be surprised if they have taken blood from 2′000 people, processed 100 of them so far and this results got it to newspaper.
Very promising (we get more test data!), but I wouldn’t draw any conclusions on this yet.
We’re finally getting some results on this. An antibody test in an Italian town an hour outside Milan has been done. 2000 people out of a population of 6169 have been tested.
Results: 13-14% of the population tested positive for the antibodies (~832 people).
The town had 27 confirmed cases, with 4 confirmed deaths. 6 deaths of all causes were recorded in March.
So this is arguably good news. It implies an IFR of about .5%. If the population here is older/unhealthier than average, as seems to be true for Northern Italy as a whole, then we could see that number dipping down further. Covid being less than an order of magnitude worse than the flu is starting to look likely but there is still a long way to go to reach herd immunity and I personally think that they should at least try for actual suppression unless we get really good numbers on the death rate and are more confident that survivors won’t have lasting side effects.
Someone in that twitter thread points out that with subtracting false positives, it implies that 10% would be the better guess, as opposed to 13-14%. Does that make sense? Then 4 Covid-confirmed deaths per 620 people would be 0.66%.
And what about sampling bias? I read that the tests were voluntary. Unless someone was extremely meticulous about trying to somehow get a representative sample, I don’t think it’s reasonable to treat this as random. It’s really quite obvious that people who had flu-like symptoms for a couple of days will be more curious to go among people and have a needle stuck into them. .
I share your rough estimates of IFR in your other comment here although I was concerned about how high IFR might be with overwhelmed hospitals.
Sampling bias at its worst here would mean that IFR is 3 times more than those calculations (i.e. 1.5-2%). If this is the worst case in Lombardy where the hospitals are overwhelmed then it is something of a relief to me that higher rates are unlikely.
Both good points. Hopefully we get more tests of the sort reported soon.
Very interesting, thanks. I think it’s 13% of tests, not 13% of entire population of 6′169, so not 832.
I don’t speak Italian and struggle to find any details. Actually they didn’t mention that all 2′000 samples were processed. On 5th April the mayor of the town posted a photo of newspaper mentioning “29% of 38 persons” positive. So I would not be surprised if they have taken blood from 2′000 people, processed 100 of them so far and this results got it to newspaper.
Very promising (we get more test data!), but I wouldn’t draw any conclusions on this yet.