• Masks are effective (Peer-reviewed: Wang JAMA 2020; MMWR Hairstylist – both used by CDC) 
• 80% people need to wear masks to be effective  (Preprint: Kai et al.)
• CDC and WHO recommend masks.
  • Note on WHO; they are a bit non-committal on strongly recommending widespread mask use among healthy individuals owing to a lack of “high quality or direct scientific evidence.” However, they recognize the growing list of observational evidence for mask use and the evidence of pre- and asymptomatic transmission, and thus advise that mask use should be encouraged in the general public to suppress transmission of SARS-CoV-2. Most recent technical document published on June 5th (keep an eye out for updated guidance and stronger support for mask use?)
    • Report titled “Advice on the use of masks in the context of COVID-19,” located partway down this link.

Efficacy of Face Masks

A CDC editorial in altering recommendations to mandate face masks. The following two articles are cited in this editorial:

• Primary article: 14 July 2020. The largest study to date in peer-reviewed research, showing mask efficacy. Wang et al. demonstrate reduced transmission in Massachusetts HCW following mask intervention, rule out other interventions.
• Primary article: 17 July 2020. Case study: July 17, 2020. “Absence of Apparent Transmission of SARS-CoV-2 from Two Stylists After Exposure at a Hair Salon with a Universal Face Covering Policy — Springfield, Missouri, May 2020”.

Largest meta-analysis to date: 27 June 2020. Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis. Chu et al (SURGE consortium). 27 June 2020. Lancet.

Adoption Critical Mass

• 21 April 2020. Preprint, not peer-reviewed. Kai et al.  Universal Masking is Urgent in the COVID-19 Pandemic: SEIR and Agent Based Models, Empirical Validation, Policy Recommendations.

Vanity fair covers the story here.

CDC

• Webpage: “CDC calls on Americans to wear masks to prevent COVID-19 spread”. July 14 2020. Call for face covering based on two pieces of literature:
  • Universal Masking to Prevent SARS-CoV-2 Transmission—The Time Is Now
• Nature article with evidence regarding lingering airborne, aerosol transmission of SARS-CoV-2 has been slow to accept, and the more scientifically proved, method of transmission of large air droplets, spread by coughing, sneezing or talking. Researchers call for more policies into building ventilation to prevent air-recirculation and possibly limit transmission

• Severity of illness in children (<18 years) and rates of admittance to ICU in the CDC Morbidity and Mortality Weekly Report, August 14th 2020:
  • Hospitalization data from 14 American states in March – July shows that rate of COVID-19 associated hospitalizations for children is low compared to adults (8.0 per 100,000, versus 164.5 per 100,000, respectively).
  • Of hospitalized children, one in three are admitted to the ICU.
  • Case fatality rate remains low. 1 of 208 cases for which a medical chart review was completed died during hospitalization. 12 of 207 cases (5.8%) required invasive mechanical ventilation.
  • MIS-C (multisystem inflammatory syndrome) discharge diagnosis collected systematically only after June 18th, but 9 of 83 children for whom chart information on MIS-C was collected received a diagnosis of MIS-C.
  • Issues with the data: summarized in report. Of note; analysis based on convenience samples for children with a final disposition and complete chart reviews. Data on MIS-C not collected until after June 18th, and issues with molecular testing mean that the percentage of MIS-C cases is likely underestimated.

• Statistics on COVID-19 cases, hospitalizations, and deaths in the US.
• Children of age 10-19 transmit COVID-19 to households at rates comparable to adults. Children age 0-9 can transmit too. Note: Transmission to householders (no masks, no distancing) higher than to non-householders. Contact tracing of 50K individuals in South Korea, linked to 5K index COVID cases. Source here.
• Children have milder symptoms than adults. Report from April, based on Wuhan.

• A national mask mandate could save the US economy $1 trillion, Goldman Sachs Says

Review article: 30 June, 2020; “COVID and the Classroom: Lessons on Reopening from Asia”. Primary and secondary school reopening measures in certain Asian countries required flexible policy making and the close monitoring of both students and regions where outbreaks were more prevalent. The countries looked at were: South Korea, Japan and China.

Article: 29 July, 2020; “Association Between Statewide School Closure and COVID-19 Incidence and Mortality in the US”. Conducted to determine if there was a relationship between school closure and decreased COVID-19 incidence and mortality. The sample consisted of a US based population and was measured in states as per 1000 residents; the researchers found that school closures correlated with a significant decrease of COVID-19 incidence, that is states that closed schools earlier had a decrease in both COVID-19 incidence and mortality.