Several Duke Margolis colleagues led by my friend and co-author, Dr. Brystana Kaufman analyzed infection rates in states that re-opened restaurants with and without mask mandates in a recent issue of the Journal of General Internal Medicine:
To estimate excess COVID-19 cases and deaths after reopening compared with trends prior to reopening for two groups of states: (1) states with an evidence-based reopening strategy, defined as reopening indoor dining after implementing a statewide mask mandate, and (2) states reopening indoor dining rooms before implementing a statewide mask mandate.
Interrupted time series quasi-experimental study design applied to publicly available secondary data.
On average, the number of excess cases per 100,000 residents in states reopening without masks is ten times the number in states reopening with masks after 8 weeks (643.1 cases; 95% confidence interval (CI) = 406.9, 879.2 and 62.9 cases; CI = 12.6, 113.1, respectively). Excess cases after 6 weeks could have been reduced by 90% from 576,371 to 63,062 and excess deaths reduced by 80% from 22,851 to 4858 had states implemented mask mandates prior to reopening. Over 50,000 excess deaths were prevented within 6 weeks in 13 states that implemented mask mandates prior to reopening.
Case counts are increasing throughout most of the country. The US-Canadian border states from Lake Superior to the Pacific are on fire at the moment. College football stadiums in Florida will be allowed to have full crowds of drunk, loud people in close proximity to each other for three to four hours on Saturdays.
Masks matter a lot.
Masks don’t solve all problems, but they seem to be sufficient to notably reduce transmission which allows for other public health interventions to be more effective.
When you leave the house; mask up!