Causal Impact of Masks, Policies, Behavior on Early Covid-19 Pandemic in the U.S

Abstract

<jats:p>This paper evaluates the dynamic impact of various policies adopted by US states on the growth rates of confirmed Covid-19 cases and deaths as well as social distancing behavior measured by Google Mobility Reports, where we take into consideration people's voluntarily behavioral response to new information of transmission risks. Our analysis finds that both policies and information on transmission risks are important determinants of Covid-19 cases and deaths and shows that a change in policies explains a large fraction of observed changes in social distancing behavior. Our counterfactual experiments suggest that nationally mandating face masks for employees on April 1st could have reduced the growth rate of cases and deaths by more than 10 percentage points in late April, and could have led to as much as 17 to 55 percent less deaths nationally by the end of May, which roughly translates into 17 to 55 thousand saved lives. Our estimates imply that removing non-essential business closures (while maintaining school closures, restrictions on movie theaters and restaurants) could have led to -20 to 60 percent more cases and deaths by the end of May. We also find that, without stay-at-home orders, cases would have been larger by 25 to 170 percent, which implies that 0.5 to 3.4 million more Americans could have been infected if stay-at-home orders had not been implemented. Finally, not having implemented any policies could have led to at least a 7 fold increase with an uninformative upper bound in cases (and deaths) by the end of May in the US, with considerable uncertainty over the effects of school closures, which had little cross-sectional variation.</jats:p>

Face masks to prevent transmission of respiratory diseases: Systematic review and meta-analysis of randomized controlled trials*

“…However, the current evidence does not support this concern [21,22]. Moreover, using data from the U.S., [23] found that mobility decreased in most settings when the policy of masks for employees started in a state. Mask mandates in Germany were associated first with a decreased mobility but had no long-term effect [24].…”

COVID-19: interpreting scientific evidence – uncertainty, confusion and delays

“…when in crowded, essential indoor spaces, like supermarkets for food shopping) have reduced the eventual COVID-19 case numbers and deaths? Recent modelling studies in the USA along these lines suggest that this was likely, where earlier interventions could have saved 30,000-40,000 American lives [41,42]. This could also be true of other countries.…”

Zorro versus Covid-19: fighting the pandemic with face masks

“…Therefore, mask wearing has an important role to play in controlling the spread of Covid-19. Given the effectiveness of mask wearing in significantly curbing the transmission of the airborne Covid-19 virus and, thus, reducing the number of infections and fatalities, it would be helpful for governments to focus more (19) and is economically attractive, we also recommend extending mandatory face mask use even for children (over 6 years of age). Attitudes regarding altruism, tolerance, and solidarity do not appear to be sufficient to achieve the necessary levels of mask wearing.…”

“…However, potential biases, especially regarding the failure to control for other non-pharmaceutical policies, have been reported. Very recently, an econometric study demonstrated the positive results of introducing masks for employees in US states in April 2020 (19). Likewise, in Germany, the introduction of mandatory mask wearing has reduced the growth rate of Covid-19 cases.…”