Some more info from Streek in Germany of a study in Heinsberg
https://www1.wdr.de/nachrichten/rheinland/corona-ergebnis-studie-heinsberg-100.html
English PDF
https://www.ukbonn.de/C12582D3002FD21D/vwLookupDownloads/Streeck_et_al_Infection_fatality_rate_of_SARS_CoV_2_infection2.pdf/$FILE/Streeck_et_al_Infection_fatality_rate_of_SARS_CoV_2_infection2.pdf
"Of the 919 individuals with evaluable infection status (out of 1,007; 405 households)
15.5% (95% CI: [12.3%; 19.0%]) were infected. This is 5-fold higher than the number of
officially reported cases for this community (3.1%). Infection was associated with characteristic
symptoms such as loss of smell and taste. 22.2% of all infected individuals were asymptomatic.
With the seven SARS-CoV-2-associated reported deaths the estimated IFR was 0.36%
[0.29%; 0.45%]. Age and sex were not found to be associated with the infection rate.
Participation in carnival festivities increased both the infection rate (21.3% vs. 9.5%, p<0.001)
and the number of symptoms in the infected (estimated relative mean increase 1.6, p=0.007).
The risk of a person being infected was not found to be associated with the number of study
participants in the household this person lived in. The secondary infection risk for study
participants living in the same household increased from 15.5% to 43.6%, to 35.5% and to
18.3% for households with two, three or four people respectively (p<0.001)."