Methodological considerations for estimating policy effects in the context of co-occurring policies.

Understanding how best to estimate state-level policy effects is important, and several unanswered questions remain, particularly about the ability of statistical models to disentangle the effects of concurrently enacted policies. In practice, many policy evaluation studies do not attempt to control for effects of co-occurring policies, and this issue has not received extensive attention in the methodological literature to date. In this study, we utilized Monte Carlo simulations to assess the impact of co-occurring policies on the performance of commonly-used statistical models in state policy evaluations. Simulation conditions varied effect sizes of the co-occurring policies and length of time between policy enactment dates, among other factors. Outcome data (annual state-specific opioid mortality rate per 100,000) were obtained from 1999 to 2016 National Vital Statistics System (NVSS) Multiple Cause of Death mortality files, thus yielding longitudinal annual state-level data over 18 years from 50 states. When co-occurring policies are ignored (i.e., omitted from the analytic model), our results demonstrated that high relative bias (> 82%) arises, particularly when policies are enacted in rapid succession. Moreover, as expected, controlling for all co-occurring policies will effectively mitigate the threat of confounding bias; however, effect estimates may be relatively imprecise (i.e., larger variance) when policies are enacted in near succession. Our findings highlight several key methodological issues regarding co-occurring policies in the context of opioid-policy research yet also generalize more broadly to evaluation of other state-level policies, such as policies related to firearms or COVID-19, showcasing the need to think critically about co-occurring policies that are likely to influence the outcome when specifying analytic models.

Methodological considerations for estimating policy effects in the context of co-occurring policies

Understanding how best to estimate state-level policy effects is important, and several unanswered questions remain, particularly about the ability of statistical models to disentangle the effects of concurrently enacted policies. In practice, many policy evaluation studies do not attempt to control for effects of co-occurring policies, and this issue has not received extensive attention in the methodological literature to date. In this study, we utilized Monte Carlo simulations to assess the impact of co-occurring policies on the performance of commonly-used statistical models in state policy evaluations. Simulation conditions varied effect sizes of the co-occurring policies and length of time between policy enactment dates, among other factors. Outcome data (annual state-specific opioid mortality rate per 100,000) were obtained from 1999 to 2016 National Vital Statistics System (NVSS) Multiple Cause of Death mortality files, thus yielding longitudinal annual state-level data over 18 years from 50 states. When co-occurring policies are ignored (i.e., omitted from the analytic model), our results demonstrated that high relative bias (> 82%) arises, particularly when policies are enacted in rapid succession. Moreover, as expected, controlling for all co-occurring policies will effectively mitigate the threat of confounding bias;however, effect estimates may be relatively imprecise (i.e., larger variance) when policies are enacted in near succession. Our findings highlight several key methodological issues regarding co-occurring policies in the context of opioid-policy research yet also generalize more broadly to evaluation of other state-level policies, such as policies related to firearms or COVID-19, showcasing the need to think critically about co-occurring policies that are likely to influence the outcome when specifying analytic models.

Hybrid immunity against reinfection with SARS-CoV-2 following a previous SARS-CoV-2 infection and single dose of the BNT162b2 vaccine in children and adolescents: a target trial emulation.

BACKGROUND: Although most children and adolescents have had a previous SARS-CoV-2 infection and many continue to receive COVID-19 vaccinations, studies of the effectiveness of hybrid immunity against reinfection with the omicron (B.1.1.529) variant are scarce. We aimed to examine the effectiveness of vaccination in convalescent children and adolescents against reinfection with the delta (B.1.617.2) variant and the BA.1 and BA.2 and BA.4 and BA.5 omicron subvariants. METHODS: This retrospective cohort study was devised to emulate a target randomised control trial using a retrospective dataset of anonymised health records of children (5-11 years old) and adolescents (12-16 years old) who were members of the Maccabi Healthcare Services, Israel. The design emulated 91 randomised trials by devising a series of multiple nested trials, compiling the results into a single dataset, and fitting Cox proportional hazards models to estimate adjusted hazard ratios (HRs) with 95% CIs of each measured outcome. The primary aim was to assess the protection from reinfection with the delta variant and the BA.1 and BA.2 and BA.4 and BA.5 omicron subvariants associated with hybrid immunity as a result of a previous SARS-CoV-2 infection followed by vaccination with the BNT162b2 (Pfizer-BioNTech) vaccine. FINDINGS: Data from between from March 1, 2020, to July 31, 2022, for 163 812 individuals (120 721 children [59 404 girls and 61 317 boys], median age 8·0 years [IQR 6·7 to 10·2]; and 43 091 adolescents [21 239 girls and 21 852 boys], median age 13·5 years [12·6 to 14·8]) were included in at least one trial. A single dose of the BNT162b2 vaccine in convalescent children and adolescents confers statistically significant protection against the delta variant (78% [95% CI 72 to 83] in adolescents and 64% [3 to 87] in children) and the omicron BA.1 and BA.2 subvariants (54% [50 to 57] in adolescents and 71% [67 to 73] in children) compared with children who had a previous infection but were unvaccinated. However, the vaccine was not found to confer statistically significant protection against the BA.4 and BA.5 omicron subvariants in adolescents (8% [-18 to 29]) and children (12% [-6 to 27]). INTERPRETATION: Decision makers in BA.4 and BA.5 dominant regions should re-examine whether convalescent individuals aged 5-16 years should receive the BNT162b2 vaccine to prevent future reinfection, especially in light of reports that show that most children and adolescents have already been infected with SARS-CoV-2. FUNDING: None.

Trends in cannabis use among U.S. adults amid the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic has had an impact on mental health and alcohol use in the US, however there is little research on its impacts on cannabis use. Considering the role of cannabis as a coping strategy or self-medicating behavior, there is a need to understand how individuals who use cannabis have adapted their use amid the pandemic. Therefore, this study examined changes in self-reported cannabis use among US adults in the context of COVID-19 pandemic by (1) describing trends of use during the first 8 months of the pandemic among adults who used cannabis in this period; and (2) characterizing trends of use within sociodemographic subgroups and by state cannabis policy status. METHODS: The sample consisted of 1,761 US adults who used cannabis at least once during the 8-month study period from the nationally representative Understanding America Study. Linear mixed-effect models were used to model changes in the number of days of past-week cannabis use across 16 waves from March 10, 2020, to November 11, 2020. RESULTS: Compared to early March, the number of days cannabis was used per week was significantly higher at the start of April (ß=0.11, 95% CI=0.03, 0.18) and May (ß=0.21,95% CI=0.05, 0.36). In subsequent months (June - November), the number of days of cannabis use attenuated to levels comparable to March. Trends of cannabis use across the study period generally did not differ across sociodemographic characteristics and state cannabis policy status. CONCLUSION: Though increases in use were marginal among many groups, the evolving pandemic and the growing concern for the mental health of segments of the U.S. population warrant close monitoring of coping behaviors, including substance use.

Prevalence of depressive symptoms in U.S. adults during the COVID-19 pandemic: A systematic review.

The COVID-19 pandemic has led to a worsening of mental health among U.S. adults. However, no review to date has synthesized the overall prevalence of population depressive symptoms in the U.S. over the COVID-19 pandemic. We aimed to document the population prevalence of depressive symptoms and psychological distress across time since the start of the COVID-19 pandemic, both to identify patterns that emerged in the literature and to assess the data sources, methods, sampling, and measurement used to examine population mental health during the pandemic. In a systematic review of the peer review literature, we identified 49 articles reporting 88 prevalence points of depressive symptoms and related constructs in nationally representative samples of U.S. adults from March 2020 to June 2021. First, we found that the average prevalence of poor mental health across studies was 12.9% for severe depression, 26.0% for at least moderate depression, and 36.0% for at least mild depression. Second, we found that women reported significantly higher prevalence of probable depression than men in 63% of studies that reported depression levels by gender and that results on statistically significant differences between racial and ethnic groups were mixed. Third, we found that the 49 articles published were based on 12 studies; the most common sources were the Household Pulse Survey (n = 15, 31%), the AmeriSpeak panel (n = 8, 16%), the Qualtrics panel (n = 8, 16%), and the Understanding America Study (n = 5, 10%). Prevalence estimates varied based on mental health screening instruments and cutoffs used. The most commonly used instruments were the Patient Health Questionnaire (PHQ) (n = 36, 73%) and the Kessler (n = 8, 16%) series. While the prevalence of population depression varied over time depending on the survey instruments, severity, and constructs reported, the overall prevalence of depression remained high from March 2020 through June 2021 across instruments and severity. Understanding the scope of population mental health can help policymakers and providers address and prepare to meet the ongoing and future mental health needs of U.S. adults in the post-COVID-19 context and beyond.

Outcomes Among Mechanically Ventilated Patients With Severe Pneumonia and Acute Hypoxemic Respiratory Failure From SARS-CoV-2 and Other Etiologies.

Importance: Early observations suggested that COVID-19 pneumonia had a higher mortality rate than other causes of pneumonia. Objective: To compare outcomes between mechanically ventilated patients with pneumonia due to COVID-19 (March 2020 to June 2021) and other etiologies (July 2016 to December 2019). Design, Setting, and Participants: This retrospective cohort study was conducted at the Johns Hopkins Healthcare System among adult patients (aged ≥18 years) with pneumonia who required mechanical ventilation in the first 2 weeks of hospitalization. Clinical, laboratory, and mechanical ventilation data were extracted from admission to hospital discharge or death. Exposures: Pneumonia due to COVID-19. Main Outcomes and Measures: The primary outcome was 90-day in-hospital mortality. Secondary outcomes were time to liberation from mechanical ventilation, hospital length of stay, static respiratory system compliance, and ventilatory ratio. Unadjusted and multivariable-adjusted logistic regression, proportional hazards regression, and doubly robust regression were used in propensity score-matched sets to compare clinical outcomes. Results: Overall, 719 patients (mean [SD] age, 61.8 [15.3] years; 442 [61.5%] were male; 460 [64.0%] belonged to a minoritized racial group and 253 [35.2%] were White) with severe COVID-19 pneumonia and 1127 patients (mean [SD] age, 60.9 [15.8] years; 586 [52.0%] were male; 459 [40.7%] belonged to a minoritized racial group and 655 [58.1%] were White) with severe non-COVID-19 pneumonia. In unadjusted analyses, patients with COVID-19 pneumonia had higher 90-day mortality (odds ratio, 1.21, 95% CI 1.04-1.41), longer time on mechanical ventilation (subdistribution hazard ratio 0.72, 95% CI 0.63-0.81), and lower compliance (32.0 vs 28.4 mL/kg PBW/cm H2O; P < .001) when compared with those with non-COVID-19 pneumonia. In propensity score-matched analyses, patients with COVID-19 pneumonia were equally likely to die within 90 days as those with non-COVID-19 pneumonia (odds ratio, 1.04; 95% CI, 0.81 to 1.35; P = .85), had similar respiratory system compliance (mean difference, 1.82 mL/cm H2O; 95% CI, -1.53 to 5.17 mL/cm H2O; P = .28) and ventilatory ratio (mean difference, -0.05; 95% CI, -0.22 to 0.11; P = .52), but had lower rates of liberation from mechanical ventilation (subdistribution hazard ratio, 0.81; 95% CI, 0.65 to 1.00) when compared with those with non-COVID-19 pneumonia. Patients with COVID-19 pneumonia had somewhat lower rates of being discharged from the hospital alive at 90 days (subdistribution hazard ratio, 0.83; 95% CI, 0.68 to 1.01) than those with non-COVID-19 pneumonia; however, this was not statistically significant. Conclusions and Relevance: In this study, mechanically ventilated patients with severe COVID-19 pneumonia had similar mortality rates as patients with other causes of severe pneumonia but longer times to liberation from mechanical ventilation. Mechanical ventilation use in COVID-19 pneumonia should follow the same evidence-based guidelines as for any pneumonia.

Teachers’ Mental Health During the COVID-19 Pandemic

With an emergence of research investigating the educational impacts of the COVID-19 pandemic, empirical studies assessing teachers' mental health throughout the pandemic have been scarce. Using a large national data set, the current study compares mental health outcomes during the pandemic between pre-K-12 teachers and professionals in other occupations. Further, we compare the prevalence of mental health outcomes between in-person and remote teachers (N = 134,693). Findings indicate that teachers reported a greater prevalence of anxiety symptoms than did those in other professions and that remote teachers reported significantly higher levels of distress than did those teaching in person. We summarize the policy implications of these results.

Shifting Medication Treatment Practices in the COVID-19 Pandemic: A Statewide Survey of Pennsylvania Opioid Treatment Programs.

OBJECTIVES: We sought to understand how opioid treatment programs (OTPs) adapted OTP operations to the COVID-19 pandemic and new federal regulations around methadone and buprenorphine. METHODS: In fall 2020, we conducted an online survey of all 103 OTPs licensed by the Pennsylvania Department of Drug and Alcohol Programs, including clinical directors. Survey domains included changes to methadone take-home and telehealth practices; overdose and diversion prevention tactics; perceptions regarding how such changes influence patient well-being; and financial/operational concerns related to the new policies and practices. We calculated descriptive statistics and conducted Chi-square test to test for differences between not-for-profit versus for-profit and large versus small OTPs. RESULTS: Forty-seven percent (46%) OTPs responded to the survey. 10% and 25%, respectively, endorsed offering telephone and video-based telemedicine buprenorphine induction. Sixty-six percent endorsed extending take-home supplies of methadone, but most indicated that these extensions applied to a minority of their patients. Most respondents agreed that provision of buprenorphine via telehealth and extended take-home methadone reduced patient burden in accessing medications and prevented exposure to COVID-19, while not significantly increasing risk of overdose. We did not find major differences in COVID-19 practice modifications by nonprofit status or size of OTP. CONCLUSIONS: In Pennsylvania, the COVID-19 pandemic led to rapid changes in provision of opioid treatment services. Findings on relatively low uptake of longer methadone take-home regimens and virtual buprenorphine initiation despite general support for these practices imply a need to further develop guidelines for best clinical practices and understand/address barriers to their implementation.

Exploring the Potential of External Control Arms created from Patient Level Data: A case study in non-small cell lung cancer.

Randomized controlled trials (RCTs) are the gold standard for evaluation of new medical products. However, RCTs may not always be ethical or feasible. In cases where the investigational product is available outside the trial (e.g., through accelerated approval), patients may fail to enroll in clinical trials or drop out early to take the investigational product. These challenges to enrolling or maintaining a concurrent control arm may compromise timely recruitment, retention, or compliance. This can threaten the study's integrity, including the validity of results. External control arms (ECAs) may be a promising augmentation to RCTs when encountered with challenges that threaten the feasibility and reliability of a randomized controlled clinical trial. Here, we propose the use of ECAs created from patient-level data from previously conducted clinical trials or real-world data in the same indication. Propensity score methods are used to balance observed disease characteristics and demographics in the previous clinical trial or real-world data with those of present-day trial participants assigned to receive the investigational product. These methods are explored in a case study in non-small cell lung cancer (NSCLC) derived from multiple previously conducted open label or blinded phase 2 and 3 multinational clinical trials initiated between 2004 and 2013. The case study indicated that when balanced for baseline characteristics, the overall survival estimates from the ECA were very similar to those of the target randomized control, based on Kaplan-Meier curves and hazard ratio and confidence interval estimates. This suggests that in the future, a randomized control may be able to be augmented by an ECA without compromising the understanding of the treatment effect, assuming sufficient knowledge, measurement, and availability of all or most of the important prognostic variables.

In-person schooling and associated COVID-19 risk in the United States over spring semester 2021.

Because of the importance of schools to childhood development, the relationship between in-person schooling and COVID-19 risk has been one of the most important questions of this pandemic. Previous work in the United States during winter 2020-2021 showed that in-person schooling carried some risk for household members and that mitigation measures reduced this risk. Schooling and the COVID-19 landscape changed radically over spring semester 2021. Here, we use data from a massive online survey to characterize changes in in-person schooling behavior and associated risks over that period. We find increases in in-person schooling and reductions in mitigations over time. In-person schooling is associated with increased reporting of COVID-19 outcomes even among vaccinated individuals (although the absolute risk among the vaccinated is greatly reduced). Vaccinated teachers working outside the home were less likely to report COVID-19-related outcomes than unvaccinated teachers working exclusively from home. Adequate mitigation measures appear to eliminate the excess risk associated with in-person schooling.

Opioid treatment program safety measures during the COVID-19 pandemic: a statewide survey.

BACKGROUND: Opioid treatment programs (OTPs) serve as daily essential services for people with opioid use disorder. This study seeks to identify modifications to operations and adoption of safety measures at Pennsylvania OTPs during the COVID-19 pandemic. METHODS: A 25-min online survey to clinical and administrative directors at all 103 state-licensed OTPs in Pennsylvania was fielded from September to November 2020. Survey domains included: 1) changes to services, client volume, hours and staffing during the COVID-19 pandemic 2) types of services modifications 3) safety protocols to reduce COVID-19 transmission 4) challenges to operations during the pandemic. RESULTS: Forty-seven directors responded, for a response rate of 45%. Almost all respondents reported making some service modification (96%, n = 43). Almost half (47%, n = 21) of respondents reported reductions in the number of clients served. OTPs were more likely to adopt safety protocols that did not require significant funding, such as limiting the number of people entering the site (100%, n = 44), posting COVID-safety information (100%, n = 44), enforcing social distancing (98%, n = 43), and increasing sanitation (100%, n = 44). Only 34% (n = 14) of OTPS provided N95 masks to most or all staff. Respondents reported that staff's stress and negative mental health (86%, n = 38) and staff caregiving responsibilities (84%, n = 37) during the pandemic were challenges to maintaining OTP operations. CONCLUSION: OTPs faced numerous challenges to operations and adoption of safety measures during the COVID-19 pandemic. Funding mechanisms and interventions to improve adoption of safety protocols, staff mental health as well as research on patient experiences and preferences can inform further OTP adaptation to the COVID-19 pandemic and future emergency planning.

Association of Non-Pharmaceutical Interventions to Reduce the Spread of SARS-CoV-2 With Anxiety and Depressive Symptoms: A Multi-National Study of 43 Countries.

Objectives: To examine the association of non-pharmaceutical interventions (NPIs) with anxiety and depressive symptoms among adults and determine if these associations varied by gender and age. Methods: We combined survey data from 16,177,184 adults from 43 countries who participated in the daily COVID-19 Trends and Impact Survey via Facebook with time-varying NPI data from the Oxford COVID-19 Government Response Tracker between 24 April 2020 and 20 December 2020. Using logistic regression models, we examined the association of [1] overall NPI stringency and [2] seven individual NPIs (school closures, workplace closures, cancellation of public events, restrictions on the size of gatherings, stay-at-home requirements, restrictions on internal movement, and international travel controls) with anxiety and depressive symptoms. Results: More stringent implementation of NPIs was associated with a higher odds of anxiety and depressive symptoms, albeit with very small effect sizes. Individual NPIs had heterogeneous associations with anxiety and depressive symptoms by gender and age. Conclusion: Governments worldwide should be prepared to address the possible mental health consequences of stringent NPI implementation with both universal and targeted interventions for vulnerable groups.

Changes in drinking days among United States adults during the COVID-19 pandemic.

AIMS: To examine changes in drinking behavior among United States (US) adults between March 10 and July 21, 2020, a critical period during the COVID-19 pandemic. DESIGN: Longitudinal, internet-based panel survey. SETTING: The Understanding America Study (UAS), a nationally representative panel of US adults age 18 or older. PARTICIPANTS: A total of 4298 US adults who reported alcohol use. MEASUREMENTS: Changes in number of reported drinking days from March 11, 2020 through July 21, 2020 in the overall sample and stratified by sex, age, race/ethnicity, household structure, poverty status, and census region. FINDINGS: Compared with March 11, the number of drinking days per week was significantly higher on April 1 by an average of 0.36 days (95% CI = 0.30, 0.43), on May 1 by an average of 0.55 days (95% CI = 0.47, 0.63), on June 1 by an average of 0.41 days (95% CI = 0.33, 0.49), and on July 1 by an average of 0.39 days (95% CI = 0.31, 0.48). Males, White participants, and older adults reported sustained increases in drinking days, whereas female participants and individuals living under the federal poverty line had attenuated drinking days in the latter part of the study period. CONCLUSIONS: Between March and mid-July 2020, adults in the United States reported increases in the number of drinking days, with sustained increases observed among males, White participants, and older adults.

Factors associated with county-level mental health during the COVID-19 pandemic.

The objective of this study is to determine county-level factors associated with anxiety, depression, and isolation during the coronavirus disease 2019 (COVID-19) pandemic. This study used daily data from 23,592,355 respondents of a nationwide Facebook-based survey from April 2020 to July 2021, aggregated to the week-county level to yield 212,581 observations. Mental distress prevalences were modeled using weighted linear mixed-effects models with a county random effect. These models revealed that weekly percentages of mental distress were higher in counties with higher unemployment rates, populations, and education levels; higher percentages of females, young adults, individuals with a medical condition, and individuals very worried about their finances and COVID-19; and lower percentages of individuals who were working outside the home, living with children, without health insurance, and Black. Anxiety peaked in April 2020, depression in October 2020, and isolation in December 2020. Therefore, United States counties experienced the mental health effects of the pandemic differently dependent upon their characteristics, and mental distress prevalence varied across time.

Associations of household structure and presence of children in the household with mental distress during the early stages of the U.S. COVID-19 pandemic.

PURPOSE: The objectives of the current study were to (1) assess associations between household structure (i.e., living with spouse compared to living alone, with children, or with a spouse and children), presence of children, and mental distress in April 2020 and change in mental distress (between April and August 2020); and (2) determine whether these associations are moderated by income or sex. PARTICIPANTS: A total of 2,214 adults aged 25-55 from the April and August 2020 waves of the Understanding America study were included in the analytic sample. STUDY METHOD: Multivariable, survey-weighted linear regression models were used to examine associations between explanatory variables (i.e., household structure and number of children) and outcome variables (mental distress in April and change in mental distress), measured via the Patient Health Questionnaire (PHQ)-4. RESULTS: In adjusted models, each additional child under the age of 12 was associated with lower mental distress in April 2020 (ß = -.30, p = .002). Having children aged 13 to 18 and household structure were not significantly associated with mental distress. In interaction models, living with children only was associated with decreased mental distress among individuals reporting low income (interaction ß = -1.28, p = .016) but not high income. Similarly, living with children only was associated with decreased mental distress in females (interaction ß = -1.09, p = .025) but not males. CONCLUSION: This study supports prior literature that demonstrates the positive association of child rearing with psychological well-being and suggests that these benefits may be present even under stay-at-home orders in the early stages of the U.S. COVID-19 pandemic. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Studying how state health services delivery policies can mitigate the effects of disasters on drug addiction treatment and overdose: Protocol for a mixed-methods study.

BACKGROUND: The United States is experiencing a drug addiction and overdose crisis, made worse by the COVID-19 pandemic. Relative to other types of health services, addiction treatment and overdose prevention services are particularly vulnerable to disaster-related disruptions for multiple reasons including fragmentation from the general medical system and stigma, which may lead decisionmakers and providers to de-prioritize these services during disasters. In response to the COVID-19 pandemic, U.S. states implemented multiple policies designed to mitigate disruptions to addiction treatment and overdose prevention services, for example policies expanding access to addiction treatment delivered via telehealth and policies designed to support continuity of naloxone distribution programs. There is limited evidence on the effects of these policies on addiction treatment and overdose. This evidence is needed to inform state policy design in future disasters, as well as to inform decisions regarding whether to sustain these policies post-pandemic. METHODS: The overall study uses a concurrent-embedded design. Aims 1-2 use difference-in-differences analyses of large-scale observational databases to examine how state policies designed to mitigate the effects of the COVID-19 pandemic on health services delivery influenced addiction treatment delivery and overdose during the pandemic. Aim 3 uses a qualitative embedded multiple case study approach, in which we characterize local implementation of the state policies of interest; most public health disaster policies are enacted at the state level but implemented at the local level by healthcare systems and local public health authorities. DISCUSSION: Triangulation of results across methods will yield robust understanding of whether and how state disaster-response policies influenced drug addiction treatment and overdose during the COVID-19 pandemic. Results will inform policy enactment and implementation in future public health disasters. Results will also inform decisions about whether to sustain COVID-19 pandemic-related changes to policies governing delivery addiction and overdose prevention services long-term.

Global trends and predictors of face mask usage during the COVID-19 pandemic.

BACKGROUND: Guidelines and recommendations from public health authorities related to face masks have been essential in containing the COVID-19 pandemic. We assessed the prevalence and correlates of mask usage during the pandemic. METHODS: We examined a total of 13,723,810 responses to a daily cross-sectional online survey in 38 countries of people who completed from April 23, 2020 to October 31, 2020 and reported having been in public at least once during the last 7 days. The outcome was individual face mask usage in public settings, and the predictors were country fixed effects, country-level mask policy stringency, calendar time, individual sociodemographic factors, and health prevention behaviors. Associations were modeled using survey-weighted multivariable logistic regression. RESULTS: Mask-wearing varied over time and across the 38 countries. While some countries consistently showed high prevalence throughout, in other countries mask usage increased gradually, and a few other countries remained at low prevalence. Controlling for time and country fixed effects, sociodemographic factors (older age, female gender, education, urbanicity) and stricter mask-related policies were significantly associated with higher mask usage in public settings. Crucially, social behaviors considered risky in the context of the pandemic (going out to large events, restaurants, shopping centers, and socializing outside of the household) were associated with lower mask use. CONCLUSION: The decision to wear a face mask in public settings is significantly associated with sociodemographic factors, risky social behaviors, and mask policies. This has important implications for health prevention policies and messaging, including the potential need for more targeted policy and messaging design.

Impact Evaluation of Coronavirus Disease 2019 Policy: A Guide to Common Design Issues.

Policy responses to coronavirus disease 2019 (COVID-19), particularly those related to nonpharmaceutical interventions, are unprecedented in scale and scope. However, evaluations of policy impacts require a complex combination of circumstance, study design, data, statistics, and analysis. Beyond the issues that are faced for any policy, evaluation of COVID-19 policies is complicated by additional challenges related to infectious disease dynamics and a multiplicity of interventions. The methods needed for policy-level impact evaluation are not often used or taught in epidemiology, and they differ in important ways that may not be obvious. Methodological complications of policy evaluations can make it difficult for decision-makers and researchers to synthesize and evaluate the strength of the evidence in COVID-19 health policy papers. Here we 1) introduce the basic suite of policy-impact evaluation designs for observational data, including cross-sectional analyses, pre-/post- analyses, interrupted time-series analysis, and difference-in-differences analysis; 2) demonstrate key ways in which the requirements and assumptions underlying these designs are often violated in the context of COVID-19; and 3) provide decision-makers and reviewers with a conceptual and graphical guide to identifying these key violations. Our overall goal is to help epidemiologists, policy-makers, journal editors, journalists, researchers, and other research consumers understand and weigh the strengths and limitations of evidence.