The Health Department will hold four free flu shot clinics for residents this fall. The first will be from noon to 5 p.m. on Sept. 21 at the town’s Endless Summer waterfront festival at Nantasket Beach. Flu clinics also will be held on Sept. 24, from 5 to 7 p.m., at the Nantasket Beach Salt Water Club; Sept. 30, from 11:30 a.m. to 1 p.m., at the Scully Senior Center; and on Oct. 9, from noon to 1 p.m., at Nantasket Pharmacy. There is no copay, but health officials ask participants to bring their health insurance or Medicare cards in case the town can be reimbursed for the service. Flu vaccine is available to people age 7 and older. More information is available by calling 781-925-2224.