This page reports dataset and analyses codes, pre-registered hypotheses, and survey used for the study published in: Grimalda, G., Buchan, N. R., Ozturk, O. D., Pinate, A. C., Urso, G., & Brewer, M. B. (2021). Exposure to COVID-19 is associated with increased altruism, particularly at the local level. Scientific reports, 11(1), 1-14. https://www.nature.com/articles/s41598-021-97234-2 The folder "Pre-registered hypotheses; Pre-analysis plan" includes reader-friendly versions of original pre-registrations of hypotheses, which are available at: https://osf.io/k74gm (for fieldwork conducted in the U.S.) and https://osf.io/z82vc (for fieldwork conducted in Italy). The files in the folder below include mathematical notation (not available in the As-Predicted pre-registration template) and a figure detailing the determination of the sample size based on power analysis. The folder "Dataset" reports data and analyses codes to reproduce results of the study. The folder "Methods" reports the different versions of the online questionnaire administered in the different treatments in the U.S. and Italy (English translation for the Italian questionnaire). The **questionnaires** (for one randomly assigned treatment condition) can be accessed at: http://moore.az1.qualtrics.com/jfe/form/SV_a5edTFcE7GB9OzY (U.S. version) and https://moore.az1.qualtrics.com/jfe/form/SV_5nbz0p9mVFq62KF/ (Italian version).