NEW YORK — Walgreens and Rite Aid have launched their annual flu shot campaigns, providing a range of vaccine options and making it easy to visit the pharmacy and get vaccinated.

This season, Walgreens pharmacies and Healthcare Clinics nationwide and Duane Reade pharmacies in New York City will offer a trivalent flu vaccine, a needle-free nasal spray, a high-dose influenza vaccine for seniors and a quadrivalent vaccine that protects against four strains of influenza. The flu vaccines are offered on a walk-in basis during all pharmacy and clinic hours, including evenings, overnights at 24-hour pharmacy locations, weekends and holidays.

Walgreens noted that, as millions of Americans have gained health insurance coverage in the past two years, over 90% of people receiving flu shots at its locations have their immunization covered under some form of insurance, often with no co-pay or other out-of-pocket cost.

“With unprecedented convenience and broader coverage than ever before from health plans and insurers, it’s not only the most important preventive measure you can take for flu season, it’s also now one of the easiest,” stated Richard Ashworth, president of pharmacy and retail operations at Walgreens.

At Rite Aid, seasonal flu shots are available during pharmacy hours without an appointment at its nearly 4,600 stores nationwide. The drug chain said it carries the standard trivalent flu vaccine — which protects against the influenza A H3N2, influenza B and influenza A H1N1 strains — and a quadrivalent flu vaccine that protects against another influenza B virus.

A high-dose flu shot for people age 65 and older also will be available in all stores. Upon request, Rite Aid pharmacists can administer an intradermal flu shot, which uses a smaller needle that is inserted into the skin instead of the muscle.

Again this flu season, Rite Aid will hold on-site workplace flu clinics, staffed by its certified immunizing pharmacists. The chain also can offer employers a voucher program, in which employees can get a flu shot voucher to use at any Rite Aid store.

“While the timing of flu season is unpredictable, outbreaks can happen as early as October, which is why it is so important to get vaccinated as early as possible,” noted Jocelyn Konrad, executive vice president of pharmacy at Rite Aid.