Mexican health authorities are presenting preliminary findings of limited serological surveys for SARS-CoV-2. Findings: of the samples studied, nearly 25% tested positive for antibodies. Around 70% of those testing positive were asymptomatic. Studies conducted from Aug to Nov.

The sample size was of around 9,400 households. But if these preliminary findings are extrapolated as an accurate picture of the extent of the outbreak, asymptomatic spread has been far more prevalent than Mexico's COVID task force has led the public to believe.

Tonight - DEC 15 - is the first time I've heard MX health officials strongly warn the public about asymptomatic spread. The task force head has repeatedly downplayed the role of asymptomatic individuals in spread. Per federal policy, free tests are only for those with symptoms.

The hospital officials presenting the prelim findings of the serology surveys should make more appearances. I've listened to most of these pressers and can't tell you HOW REFRESHING it is to hear a health official roundly condemn the approach of "herd immunity" through infection.

Tonight's presentation is also the first time in a long, long while medical professionals who *actually work in hospitals treating COVID-19* are speaking to the public and taking questions from the press. More of this please

Early in the pandemic, Mexico's "coronavirus czar" repeatedly implied herd immunity through surviving infection was going to be the way out. What prelim findings presented tonight show is that this strategy brought mass mortality for not enough antibodies to slow viral spread.

Something else the prelim seroprevalence survey findings show is that the "Sentinel surveillance" model used by federal authorities to calculate the dimensions of the outbreak was grossly insufficient. This was obvious, but now there's additional evidence. https://mobile.twitter.com/Alejand17987688/status/1339021512586747904