Proceedings of the National Academy of Sciences

Epidemic control depends not only on policy mandates but also on endogenous behavioral responses--how individuals adjust private preventive actions to evolving risk. Using over 1.1 million county-day observations from 1,206 U.S. counties, we integrate high-frequency mobility data with local COVID-19 mortality to estimate the semi-elasticity of preventive behavior to mortality-driven risk perception. Fixed-effects regressions exploit within-county temporal variation, controlling for day-of-week a...

Using high-frequency panel data for U.S. counties, I estimate the full dynamic response of COVID-19 cases and deaths to exogenous movements in mobility and weather. I find several important results. First, holding mobility fixed, temperature is found to have a negative and significant effect on COVID-19 cases from 1 to 8 weeks ahead and on deaths from 2 to 8 weeks ahead. Second, holding weather fixed, mobility is found to have a large positive effect on subsequent growth in COVID-19 cases and de...

We develop an ECON-EPI network model to evaluate policies designed to improve health and economic outcomes during a pandemic. Relative to the standard epidemiological SIR set-up, we explicitly model social contacts among individuals and allow for heterogeneity in their number and stability. In addition, we embed the network in a structural economic model describing how contacts generate economic activity. We calibrate it to the New York metro area during the 2020 COVID-19 crisis and show three m...

We model the evolution of the number of individuals that are reported to be sick with COVID-19 in Germany. Our theoretical framework builds on a continuous time Markov chain with four states: healthy without infection, sick, healthy after recovery or after infection but without symptoms and dead. Our quantitative solution matches the number of sick individuals up to the most recent observation and ends with a share of sick individuals following from infection rates and sickness probabilities. We...

Research on maternal-fetal epigenetic programming argues that adverse exposures to the intrauterine environment can have long-term effects on adult morbidity and mortality. However, causal research on epigenetic programming in humans at a population level is rare and is often unable to separate intrauterine effects from conditions in the postnatal period that may continue to impact child development. In this study, we used a quasi-natural experiment that leverages state-year variation in economi...

While COVID-19 was already responsible for more than 500,000 deaths worldwide as of July 3, 2020, very little is known on the socio-economic heterogeneity of its impact on mortality. In this paper, we combine several administrative data sources to estimate the relationship between mortality due to COVID-19 and poverty at a very local level (i.e. the municipality level) in France, one of the most severely hit country in the world. We find strong evidence of an income gradient in the impact of the...

The 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 peoples voluntarily behavioral response to new information of transmission risks in a causal structural model framework. Our analysis finds that both policies and information on transmission risks are important determinants of Covid-19 cases and deaths ...

Suicides cause more than 49,000 deaths per year in the United States, including 55% associated with the use of a firearm. Across states and counties in the US, suicide mortality exhibits substantial geographical and sociodemographic heterogeneity. However, the role of large-scale social networks in shaping this variation remains underexplored. To assess how both the risk of suicide mortality and the effect of firearm restriction policies propagate through inter-county social ties, we integrate d...

Discussion on the disproportionate impact of COVID-19 on African Americans has been at center stage since the outbreak of the epidemic in the United States. To present day, however, lack of race-disaggregated individual data has prevented a rigorous assessment of the extent of this phenomenon and the reasons why blacks may be particularly vulnerable to the disease. Using individual and georeferenced death data collected daily by the Cook County Medical Examiner, we provide first evidence that ra...

The transmission of respiratory pathogens is fundamentally shaped by human behaviors such as interpersonal contacts, use of face masks, and vaccination. Political party affiliation has been shown to be associated with health-related behaviors. Yet, partisan heterogeneity in health-related behaviors is typically not included in infectious disease transmission models. Here, we leveraged uniquely detailed data from the Berkeley Interpersonal Contacts Study (BICS) on partisan differences in contact ...

We use the synthetic control method to analyze the effect of face masks on the spread of Covid-19 in Germany. Our identification approach exploits regional variation in the point in time when face masks became compulsory. Depending on the region we analyse, we find that face masks reduced the cumulative number of registered Covid-19 cases between 2.3% and 13% over a period of 10 days after they became compulsory. Assessing the credibility of the various estimates, we conclude that face masks red...

Many countries consider the lifting of restrictions of social contacts (RSC). We quantify the effects of RSC for Germany. We initially employ a purely statistical approach to predicting prevalence of COVID19 if RSC were upheld after April 20. We employ these findings and feed them into our theoretical model. We find that the peak of the number of sick individuals would be reached already mid April. The number of sick individuals would fall below 1,000 at the beginning of July. When restrictions ...

We evaluate impacts heterogeneity of an Early Childhood Intervention in Colombia, with respect to the Educational Attainment Polygenic Score (EA4 PGS) constructed from DNA data based on GWAS weights from a European population. We find that the EA4 PGS is predictive of several measures of child development, mothers IQ and, to some extent, educational attainment. We also show that the impacts of the intervention are significantly greater in children with low PGS, to the point that the intervention...

We present an age-stratified SEIR-type model of the Norwegian population, which is extended to include the effects of broad types of Non-Pharmaceutical Interventions (NPIs) like general lockdown-policies, contact tracing and quarantine and border control. The model can be used to explore the spread of a new virus with given virulence and transmissibility, and to assess the main costs of the disease and the NPIs in terms of lost health and welfare as well as economic losses. We define the optimal...

We quantify the causal impact of human mobility restrictions, particularly the lockdown of the city of Wuhan on January 23, 2020, on the containment and delay of the spread of the Novel Coronavirus (2019-nCoV). We employ a set of difference-in-differences (DID) estimations to disentangle the lockdown effect on human mobility reductions from other confounding effects including panic effect, virus effect, and the Spring Festival effect. We find that the lockdown of Wuhan reduced inflow into Wuhan ...

Governments around the world have adopted unprecedented policies to deal with COVID-19. This paper zooms in on business shutdowns and investigates their effectiveness in reducing mortality. We leverage upon highly granular death registry data for over 4,000 Italian municipalities in a diff-in-diff approach that allows us to credibly mitigate endogeneity concerns. Our results, which are robust to controlling for a host of co-factors, offer strong evidence that business shutdowns are very effectiv...

The COVID-19 pandemic underscored the importance of countries interconnections in understanding and reacting to the spread of the virus. This paper uses a global model with a sample of 41 countries to study the interdependencies between COVID-19 health shocks, populations risk perceptions about the disease, and their social distancing responses; it also provides some early evidence about potential economic effects. Social networks are a central component in understanding the international tran...

We examine the mortality effects of a 1947 school reform in Japan, which extended compulsory schooling from primary to secondary school by as much as 3 years. The abolition of secondary school fees also indicates that those affected by the reform likely came from disadvantaged families who could have benefited the most from schooling. Even in this relatively favorable setting, we fail to find that the reform improved later-life mortality up to the age of 87 years, although it significantly incre...

Due to network effects, Contact Tracing Apps (CTAs) are only effective if many people download them. However, the response to CTAs has been tepid. For example, in France less than 2 million people (roughly 3% of the population) downloaded the CTA. Against this background, we carry out an online experiment to show that CTAs can still play a key role in containing the spread of COVID-19, provided that they are re-conceptualized to account for insights from behavioral science. We start by showing t...

The COVID-19 Vaccines Global Access (COVAX) is an initiative led by the World Health Organization (WHO) and other partners that aims for an equitable access of COVID-19 vaccines. Despite a potential heterogeneous disease burden across space, countries receiving allotments of vaccines via COVAX may want to follow WHOs allocation rule and distribute vaccines to their jurisdictions based on the jurisdictions relative population size. Utilizing economic-epidemiological modeling, we benchmark the per...