New information. The Italian town of Vo was blanket-RNA-tested twice in late February and early March. A total of 3% of the town tested positive, and they were able to lock down this subset and shut down transmission from continuing in the town indicating they caught enough of the asymptomatic-but-transmissive carriers.
Here we have a detailed analysis of these positive-testing people.
43% asymptomatic all the way through.
~20% hospitalized. This means almost 40% hospitalization of people who were symptomatic. Critera for hospitalization is an interesting question, as is the age breakdown of the town.
One death, in a town in which a total of 82 people tested positive. That one death was what alerted authorities to the outbreak in the town, so we need to take it as a given rather than taking it as even weak evidence of an over 1% fatality rate.
No cases among hundreds of children, even in houses with symptomatic family members. Extra cases among the elderly (as in 1% of 20 year olds versus 6% of 70 year olds). Small numbers but significant. Unclear if that means they are not getting infected or are not producing long-lasting infection that is detectable or if social structure has something to do with it.
No obvious difference in symptomatic versus asymptomatic across the age distribution, subject to sample size.
More men took more than 2 weeks to clear the virus than women.
Definite confirmed asymptomatic people passing it on, and presymptomatic people passing it on.
3% of the town testing positive via PCR in the beginning of March is compatible with 15% of other towns in the area testing positive via serology a month later, as that would be less than 3 doublings. They find a ‘serial interval’ of only about 7 days in their contact-tracing data from before the lockdown, and 10 days after the lockdown, and a replication number before the lockdown of about 3 and 0.14 during the lockdown. That’s a doubling time of well under a week before the lockdown. The rest of Italy’s lockdown didn’t include such good contact tracing and thus still was probably doubling a few times during that period.
New information. The Italian town of Vo was blanket-RNA-tested twice in late February and early March. A total of 3% of the town tested positive, and they were able to lock down this subset and shut down transmission from continuing in the town indicating they caught enough of the asymptomatic-but-transmissive carriers.
https://www.medrxiv.org/content/10.1101/2020.04.17.20053157v1
Here we have a detailed analysis of these positive-testing people.
43% asymptomatic all the way through.
~20% hospitalized. This means almost 40% hospitalization of people who were symptomatic. Critera for hospitalization is an interesting question, as is the age breakdown of the town.
One death, in a town in which a total of 82 people tested positive. That one death was what alerted authorities to the outbreak in the town, so we need to take it as a given rather than taking it as even weak evidence of an over 1% fatality rate.
No cases among hundreds of children, even in houses with symptomatic family members. Extra cases among the elderly (as in 1% of 20 year olds versus 6% of 70 year olds). Small numbers but significant. Unclear if that means they are not getting infected or are not producing long-lasting infection that is detectable or if social structure has something to do with it.
No obvious difference in symptomatic versus asymptomatic across the age distribution, subject to sample size.
More men took more than 2 weeks to clear the virus than women.
Definite confirmed asymptomatic people passing it on, and presymptomatic people passing it on.
3% of the town testing positive via PCR in the beginning of March is compatible with 15% of other towns in the area testing positive via serology a month later, as that would be less than 3 doublings. They find a ‘serial interval’ of only about 7 days in their contact-tracing data from before the lockdown, and 10 days after the lockdown, and a replication number before the lockdown of about 3 and 0.14 during the lockdown. That’s a doubling time of well under a week before the lockdown. The rest of Italy’s lockdown didn’t include such good contact tracing and thus still was probably doubling a few times during that period.