This paper employed a segmented Poisson model to analyze the available daily new cases data of the COVID-19 outbreaks in Canada, France, Germany, Italy, UK and USA. Their model predicts that the USA will have the most confirmed cases in this group (also in the world).
The authors incorporated the government interventions (stay-at-home advises/orders, lockdowns, quarantines and social distancing) against COVID-19 into the model and predicted the turning point (the time that the daily new cases peak), the duration (the period that the outbreak lasts) and the attack rate (the percentage of the total population that will be infected over the course of the outbreak) for these countries.
They predict that among these six countries, France will have the highest attack rate (0.3364%), while Canada will have the lowest attack rate (0.0899%). The USA will have the most cumulative cases (835,158), Canada’s cumulative cases (33,948) would be the least. On average, they predict the turning point will occur at day 69 (in the range of 56 - 78). They predict that if the current government actions remain unchanged, outbreaks would likely to end at the beginning of June (ranging from May 21 to June 10) and that outbreaks will last an average of 127 days (ranging from 115 to 138 days).
For the USA specifically, their analysis found that the turning point was April 07 (in the range of April 03 - April 09), the outbreak will end in the early June (June 03), and the cumulative cases will be about 835,158, i.e., the attack rate will be 0.2523%.