A corpsman from Naval Air Station, Joint Reserve Base, Belle Chasse, administers a flu shot to a Marine at MarForRes Headquarters Oct. 27, 2010. Vaccination is mandatory for all service members. - A corpsman from Naval Air Station, Joint Reserve Base, Belle Chasse, administers a flu shot to a Marine at MarForRes Headquarters Oct. 27, 2010. Vaccination is mandatory for all service members.