THINK LIKE AN EPIDEMIOLOGIST: Lately I have been asked why we are seeing a dramatic turnaround in cases in the US. Is it vaccines? Herd immunity? An artifact due to a drop in testing? Behavior change? Weather?? A few tweets about how I step through this question. 1/6 pic.twitter.com/AJ12wvFPX2

— Natalie E. Dean, PhD (@nataliexdean) February 17, 2021