What is the recommended month in Switzerland for people to get the flu shot? Is September too early?

Yes. I think it usually starts mid october

Mid-October to Mid-November.

Got it, thanks!

If you get the flu shot from your GP practice, check with them - it depends on when the flu shot is made available to general practices. If you regularly see a specialist like an oncologist, you can often get your shot a bit earlier. As others have said, it’s usually mid October, but I’ve had them as early as late September.

I used to regularly travel to the US in October and always tried to get my shot before traveling.

I ask in the Pharmacy. They ask a few questions and then tell me when it'll be available to me. They tend to do vulnerable groups first.

Apparently flu reaches highs in late winter normally, and the vaccine is waning quite a bit. Last year I heard recommendations for as late as possible, i.e. late November ideally. Then again, couldn't get any last year at all.

My GP usually has the jab in stock by the beginning of November, and often runs out of their allocation by end of November. One year I waited too long, early December, and ended up out of luck, no flu jab to be had anywhere in SZ.

In October you should call your GP to ask if they know when the jab will be available, and ask if it is possible to reserve or register interest. Some GPS will do that for at-risk patients, but often it’s simply first come first served.