Growth rate and acceleration analysis of the COVID-19 pandemic reveals the effect of public health measures in real time

Yuri Tani Utsunomiya; Adam Taiti Harth Utsunomiya; Rafaela Beatriz Pintor Torrecilha; Silvana Cassia Paulan; Marco Milanesi; Jose Fernando Garcia

where t is a time point, a is the asymptote (i.e., number of cases at the stationary stage), exp is the exponential function, k is a growth coefficient and d is the time at inflection of the exponential stage (i.e., time when the growth rate reaches its maximum value and acceleration transitions from positive to negative). All simulations were performed considering a 100-days period, with parameters sampled as follows: a ~ Uniform(500, 10000), k ~ Uniform(0.05, 0.95) and d Ũ niform (5, 95) . Completely stationary curves were discarded. The accuracy of growth rate and acceleration estimates produced by MR with smooth factor ranging from s = 3 to s = 10 were then evaluated by taking the coefficient of determination (R²) of the regression of true values onto estimates.