Can anyone confirm these serology testing results from Oise France (see thread for details)? If the immunity ratio in this region is 10%, that implies a very low ascertainment rate (confirmed cases / total infections) - next tweet for calculation. https://twitter.com/MosconeF/status/1247873450854809600

Oise has a population of about 820,000. Statista reports 1,753 confirmed cases in all of Hauts-de-France (in which Oise is located) as of March 25. If 10% immunity, that implies 82,000 infections in Oise. Suggests upper bound of C/I =1,753/82,000 = 2.1% https://www.statista.com/statistics/1101388/coronavirus-france-confirmed-cases/

Of course, this depends on testing rates, which vary substantially. But even this low immunity rate suggests that only about 2% of current plus past infections are confirmed as of the end of March in one region of France. Thoughts?