2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/165488We propose two simple probability models to compute the probability of an influenza pandemic. Under a random walk model the probability that all pandemics between times 0 and 300 occur by time 150 is 1/2. Under a Poisson model with mean inter arrival time of 30 years the probability that no pandemic occurs during at least 60 years is 14%. These probabilities are much higher than generally perceived. So yes the next influenza pandemic will happen but maybe much later than generally thought.ProbabilityPopulations and Evolution60K35, 92D30text