Thread by @DrWmPadula

Many have been talking excitedly about how 6-straight weeks of declining #COVID19 Cases are an indicator that USA reaching natural herd immunity in the next 4-6 weeks. Here are a bunch of reasons why that is bogus... #CoronavirusPandemic #vaccines

1. 28.2 Million COVID cases in USA. Undoubtedly an underestimate due to lack of testing for symptomatic and asymptomatic cases, but far short of any relevant number to herd immunity in a population of 300+ million. GAVI says you need >65% immunization to protect herd

2. 7.73 Million #Vaccine Doses Given, only about 2.1 million fully vaccinated. Doesn't get us any closer to 65% immunization if combining vaccinated and previously infected

3. 195 million vaccinated or previously infected within 12 months is the MAGIC Number to herd immunity

4. We don't know how long people have a natural immune response to #COVID19. Thus, if people started to become infected in USA back in Jan/Feb/Mar 2021, then those individuals could quickly shift back into the Susceptible population in coming months.

5. We don't know how long the vaccine immunization will last either. The idea of herd immunity will continue to be a revolving door, dependent on diligence to re-vaccinate on an annual basis

6. 6-weeks of declining cases is far less of a statistically significant trajectory than Walter Shewhart would accept on a final exam. Shewhart explains that 8 consecutive, incremental data points are necessary to claim a sustained shift above or below a central tendancy.

7. If the vaccine is the most practical technological solution to reach herd immunity, then why tell people we are almost there naturally. From a commonsense public health perspective, public health researchers should report good news with respect to individuals vaccine diligence

Recommendation: Cool it on pre-mature discussions about natural herd immunity and keep eyes on the prize of vaccine rollout. Enormous tech achievement 2 short months ago #OperationWarpSpeed. Take pride in that! @dbishai @loganbrenzel @immeconomics @withyouDrWu @nursingdean

PS: our #COVID19 rates for the past 12 months look like #dogecoin stock. Scrutinize our data. Don't assume that we've reached a floor or a ceiling yet. Remain diligently to protect against infection with PPE, Social Distancing, and get vaccinated when you can. @rekatz