"Flu activity" refers to the level of influenza virus spread and the number of people who are sick with the flu at a given time. It helps to measure how active and widespread the flu is in a specific area or population. Full definition
So, it's possible that there is no more flu activity in that area. (wormsandgermsblog.com)
There's widespread flu activity across the country, a vaccine that's not all that effective, and an onslaught of news stories of flu - related deaths. (health.com)
The news that we may not have even hit peak flu activity yet is almost too much to take. (health.com)