WOONSOCKET, RI -- Drugstore operator CVS Caremark Corp. (CVS:NYSE) said Monday it will give away 100,000 free seasonal flu shots to unemployed people.

Beginning Tuesday, seasonal flu shots will be available daily without an appointment at more than 500 MinuteClinic locations inside select CVS/pharmacy stores.

The company will give out vouchers for the free shots at its pharmacies and MinuteClinics. The company said the free shots will cost it about $3 million.

CVS rivals Rite Aid and Walgreen also said they will dispense flu shots beginning this week.

The companies have moved up their seasonal flu shot clinics because they expect greater demand for the vaccine due to Americans' concerns about swine flu. The vaccine being offered this week is intended to prevent the seasonal flu and is separate from vaccines for swine flu. A swine flu vaccine could be ready by mid-October.

The Centers for Disease Control and Prevention recommends the vaccine for children, the elderly, caregivers, pregnant women, and people with weak immune systems or many other chronic health problems.