Sistema FMUSP-HC: Faculdade de Medicina da Universidade de São Paulo (FMUSP) e Hospital das Clínicas da FMUSPALBANI, V. V. L.ALBANI, R. A. S.MASSAD, E.ZUBELLI, J. P.2022-10-262022-10-262022ROYAL SOCIETY OPEN SCIENCE, v.9, n.8, article ID 220489, 13p, 20222054-5703https://observatorio.fm.usp.br/handle/OPI/49259We propose a parsimonious, yet effective, susceptible-exposed-infected-removed-type model that incorporates the time change in the transmission and death rates. The model is calibrated by Tikhonov-type regularization from official reports from New York City (NYC), Chicago, the State of Sao Paulo, in Brazil and British Columbia, in Canada. To forecast, we propose different ways to extend the transmission parameter, considering its estimated values. The forecast accuracy is then evaluated using real data from the above referred places. All the techniques accurately provided forecast scenarios for periods 15 days long. One of the models effectively predicted the magnitude of the four waves of infections in NYC, including the one caused by the Omicron variant for periods of 45 days using out-of-sample data.engopenAccessepidemiological modelsnowcastingforecastingCOVID-19model calibrationdynamicsepidemicarticleCopyright ROYAL SOC10.1098/rsos.220489Multidisciplinary Sciences