The most commonly used test for the presence of SARS-CoV-2 is a PCR test that is able to detect very low viral loads and inform on treatment decisions. Medical research has confirmed that many individuals might be infected with SARS-CoV-2 but not infectious. Knowing whether an individual is...

How do people form beliefs about novel risks, with which they have little or no experience? A 2020 US survey of beliefs about the lethality of Covid reveals that the elderly underestimate, and the young overestimate, their own risks, and that people with more health adversities are more...

We introduce a model of the diffusion of an epidemic with demographically heterogeneous agents interacting socially on a spatially structured network. Contagion-risk averse agents respond behaviorally to the diffusion of the infections by limiting their social interactions. Firms also respond by...

Recent observations on countries like the UK that have accumulated a large fraction of inoculated individuals suggest that, although initially, vaccines have little effect on new infections they strongly reduce the share of mortality out of a given pool of infections. This paper examines the...

While the COVID-19 pandemic has laid bare the large costs of infectious diseases, less attention has been paid to the impacts of more common, endemic respiratory viruses that frequently circulate in the population, especially when it comes to their potential long-term consequences for population...

This paper estimates time-varying COVID-19 reproduction numbers worldwide solely based on the number of reported infected cases, allowing for under-reporting. Estimation is based on a moment condition that can be derived from an agent-based stochastic network model of COVID-19 transmission. The...

Can informing people of high rates of community support for social distancing encourage them to do more of it? Our Mozambican study population underestimated the rate of community support for social distancing, believing support to be only 69%, while the true share was 98%. In theory, informing...

Domestic mobility restrictions to control the spread of COVID-19 are widespread in developing countries, and have trapped millions of migrant workers in hotspot cities. We show that bans can increase cumulative infections relative to a counterfactual sans restrictions. A SEIR model shows bans'...

Using randomized methodologies, we study a common community HIV/AIDS program that seeks to promote HIV testing by improving knowledge and reducing stigmatizing attitudes. Contrary to expectations, the program has a substantial negative effect on HIV testing rates. We provide evidence of likely...