I received the flu shot (quadrivalent) oct. 2. is there an ideal time to get the shot to maximize its protective effect (early fall vs winter)?

Weeks before season: Getting a flu shot 2-6 weeks before the first local cases of influenza beging appearing would be a good time. However, we can't have the entire country go to the doctor, the pharmacy, or the company health clinic all in a 4 week time span. That would be very crowded and inefficient. Thus, for flu seasons that start in late November, it's fine to get a shot between late-August and late-November.