If you do nothing else the next few days, get a flu shot. The best time to get a flu shot is by the end of October, the Centers for Disease Control and Prevention advises. Considering the severity of last year’s flu, it is especially important for everyone over age six months to be vaccinated. This includes pregnant women.

The current 2017-18 flu season is a bad one. Hospitalization rates are now higher than in recent years at the same point, and infection rates are still rising. The best line of defense is the seasonal influenza vaccine. But H3N2 viruses, like the one that’s infecting many people this year, are particularly hard to defend against, and this year’s shot isn’t very protective against H3N2.

Flu season is coming, and while many employers are deploying on-site vaccination programs for their employees, uptake and impact vary across countries and business sectors. Through a review of messages from public health institutions worldwide, we discuss below the pros and cons, trends so far, and expectations for the new season.