PMC estimates that US SARS-CoV-2 transmission is higher than 62% of all days since pandemic onset. We are very much #DuringCOVID. The current wave is atypical in two respects. 1) We have a pronounced double peak. The secondary rise in early October violates historical trends. 2) Real-time data quality are terrible. About 1-in-6 CDC contractor sites are offline while a contractor issue is resolved. Additionally, each of the past 6 weeks, the CDC has retroactively corrected levels upward. The magnitude and scope of the corrections are highly atypical. In each case, the corrections go back until early July. In each case, levels increase about 25-40% between the time they are reported and two weeks later, with additional upward corrections as time goes by. These are not one-off corrections, and hence, not related to the twice-annual calibration process or specific sites coming online. It's basically like a balloon is sitting under the wave, and each week, the balloon gets inflated a little more, pushing each phase of the wave higher and higher, week after week. We've added a new feature to our diagnostic systems and hope to have more insight into that soon. Expect that the wave shape may look vastly different in a couple months when the full delayed data come in. THREAD (2/4)

The recirculation "feature" in cars is extremely dangerous. It increases risk of SARS-CoV-2 transmission immensely in rideshares. The CO2 level itself also promotes drowsiness and cognitive dysfunction, risk factors for accidents. If you have a CO2 monitor, use it while driving with recirc on for 15 mins. You will not be able to unsee the result, and I doubt you will ever do it again.