Sanofi Pasteur announced it had shipped the first of its 2016-2017 seasonal influenza vaccine doses this week. The company, the world’s largest flu vaccine manufacturer, said it expected to ship 65 million vaccine doses.

Around 60% of vaccinated seniors are expected to receive Fluzone High-Dose vaccine this season, the company said.

Flu activity generally starts in October and peaks from December to February. However, the company noted last season’s peak was in early March 2016.

In the 2014-2015 season, the Centers for Disease Control and Prevention estimated there will be 40 million flu illnesses, 19 million flu-associated medical visits and almost a million flu-associated hospitalizations.

The Fluzone High-Dose vaccine was designed specifically for those over age 65. Studies have indicated it is more than 50% more effective than the Fluzone vaccine against influenza caused by viral strains antigenically similar to those contained in the vaccine using a modified CDC influenza-like illness definition, the company noted.