Stages Of The Flu 2025. Cdc uses the estimates of the burden of flu in the population and the impact of flu vaccination to inform policy and communications related to flu. People who have flu often feel some or all of these signs and symptoms:
Flu symptoms progress through four different stages, from incubation to recovery. Flu symptoms tend to occur in three stages and include days 1 through 3 in the first stage with a sudden appearance of symptoms, day 4 in the second stage as new symptoms appear, and.
