Many drug stores are offering flu shots earlier than in past years in line with a federal recommendation that everyone older than six months be vaccinated this season.

The three largest national chains will be selling flu shots by next week.

Rite Aid Corp. said Thursday that flu vaccinations are now available at most of its stores. Walgreen Co., the nation's largest drug chain, started selling the shots Tuesday. And stores run by No. 2 CVS Caremark Corp. will start selling flu shots next week.

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Rite Aid said about 3,000 of its pharmacies are selling vaccinations against the 2009 swine flu, influenza B and the H3N2 flu strain for $24.99 each. A booklet with more than $100 in coupons comes with each shot while supplies last.

The Camp Hill, Pa., company, which has 4,800 stores in 31 states, plans to host flu clinics at 800 more stores in October and November.

The chains are moving up the start of flu shot season in the wake of last year's swine flu outbreak. Last year's Sept. 1 start was already a month earlier than in previous years.

Walgreen, based in Deerfield, Ill., said some of its stores started offering the shots last week.

CVS, based in Woonsocket, R.I., said nearly all its 7,100 stores and all 500 of its in-store MinuteClinics will sell flu shots.

In previous years, the federal Centers for Disease Control and Prevention recommended shots for more specific groups, such as the elderly and people with compromised immune systems. In February, it recommended vaccinations for everyone older than six months.

Rite Aid shares fell nearly 3 cents, or nearly 3 percent, to close at 96 cents Thursday as the market fell overall.

CVS shares lost 53 cents, or 1.8 percent, to close at $28.52. Walgreen stock slipped 5 cents to $28.16.