Thread by @DrTracyTaylor

1/ @APDillon_ @JohnLockeNC @NC_Governor @SecMandyCohen Let’s discuss NC Executive Order 180 (governor.nc.gov/documents/exec…) and the evidence/studies cited for having stricter guidelines, shall we?

2/ 1.1st study cited published 6/16/20: data examined included (+) rates 3/31-5/22 anywhere from 1-21 days after mask mandate. Study cites ⬆️ mask use/mandates for 15 states, DC, + 29 counties & NYC. See graphs to compare a few things: timeframe, curve shapes & timeframe to

3/ today (DE, MD, MA). Then compare to some states w/o mandates (SD, GA, SC). Then compare to NC w/our mandate effective on 6/30.

4/

5/ 2. 2nd study published 6/1/20 used observational studies (weak evidence) w/findings of social distancing >/= 1 m (3 ft) + N95 (or disposable surgical or 12-16 LAYER cotton mask) + goggles or face shield possibly beneficial w/in household w/infected person. Specifically:

6/ a. “A physical distance of >1m probably results in large ⬇️ in virus infection,” w/moderate certainty meaning true effect close to estimate but could be substantially different from effect estimate,

7/ b. “N95 or face mask use (disp surg or 12-16 LAYER cotton) by those exposed to infected indiv was assoc w/large infxn risk ⬇️, w/stronger assoc in healthcare settings compared to non-HC settings (low to mod credibility).” After adjustment, subgroup effect was less credible.

8/ c. Eye protection associated w/⬇️ infexn risk w/low certainty.
“N95 might be associated w/larger degree of protection than disposable medical masks or multilayer (12-16 LAYER) masks. However, due to data limitations, certainty is not high.”

9/ 3rd study published 6/30/20 has a correction & associated letters. 1st letter (10/6/20) discusses SC-2 epidemiology/⬇️ in transmission rates w/respect to lockdowns & face masks in NYC. Paragraph 3 in this letter states that authors, “ oversimplify day to day fluctuations &

10/ erroneously apply linear regression to data b/w April 17 & May 9 in NYC & b/w April 5 & May 9 in US,” & that nonlinear regression or more explicit epidemiological model is more appropriate. The 2nd letter (11/3/20) points out that:

11/ a. Too few epidemiological curves to draw conclusion,
b. Lack of differentiation b/w settings, & PPE supplies,
c. The authors did not control for or analyze confounding variables assoc w/wearing face covering,

12/ d. Coronavirus infexns usually seasonal infexns resulting in flattened curve toward the summer,
e. Different epidemiological curves for US & NY shown might be due to differences of seasonality for NY alone & entire US including southern states where epidemic arrived later,

13/ f. Cases counted by PCR detection & don’t include clinical infexn status. See pic of NY’s Covid cases to date.

14/ 4th “study” (published 6/2020) cited is actually discussion paper series, & reports case ⬇️ 10 days after mask mandate. We know based on current epidemiological evidence that we’d not see an effect for ~2-3 wks after a mask mandate (see above). Also, control group is a

15/ synthetic control, & then the tx group is compared to it; it’s a statistical model used to compare an intervention (mask mandate) in comparative case studies. It’s extremely weak evidence. See the graph of Germany Covid cases.

16/ 5th “study” (published 6/29/20) isn’t a study but rather a position statement arguing for mask mandate, & cites US mask wearing compliance at ~70%, Nordic mask wearing compliance at 10%. Compare Nordic graphs to US graphs. The study then compares data in 20 states w/mask

17/ mandates from 4/8 to 6/24. Authors report that states w/mask mandates experienced a lower avg daily growth rate in confirmed infections over 1 wk. See all graphs. Notice all curves. Look at scale on left of each graph & compare.
The Governor & Cohen used extremely weak & old

18/18 evidence to tighten restrictions in NC. Again, they omit key details/information necessary for NC citizens to make informed decisions.