WellPoint, one of the nation's largest health insurers and the parent company of Anthem Blue Shield, has withdrawn a Medicare Advantage health plan that enrolled 1,252 persons in Sonoma County, according to the Centers for Medicare and Medicaid.

The centers said it is working to ensure that the affected beneficiaries know they’re losing their Medicare Advantage plan for 2013. People with Medicare in Sonoma County still have seven Medicare Advantage plans to choose from for next year.

Medicare beneficiaries losing their Medicare Advantage plans also have the option of switching to original Medicare, according to the centers (CMS).

Medicare Advantage plans are operated by private insurers under contract with CMS. Such plans typically cover all the same benefits and services as original Medicare. Those with Medicare can sign up for or switch Medicare Advantage plans and Medicare standalone prescription drug (Part D) plans during Medicare’s open-enrollment period, which began Oct. 15 and ends Dec. 7.

In an email, Wellpoint spokeswoman Leslie Porras said the HMO pulled the plan in Sonoma County based on a number of factors.

"Anthem’s decision to discontinue and reduce the service area of certain affiliated (Medicare Advantage) plans effective Jan. 1, 2013, was made after evaluating member needs, affordability, cost and long-term sustainability.  What’s important to note is that Anthem will be introducing a new plan – members in Sonoma County can now select  Anthem Medicare Preferred Standard (PPO)."

Jack Cheevers, a spokesman for CMS in San Francisco, said it's typical for an insurer to pull one plan and replace it with another, often with different premiums, co-pays and benefits. The removal of the plan could also be an indication that the insurer was losing money on the plan or having difficulty putting together a strong provider network,  which is often the case in more rural counties.

CMS urged those affected by the change to contact the Health Insurance Counseling and Advocacy Program, a nonprofit counseling service for Medicare recipients: Senior Advocacy Services, 3262 Airway Dr., Suite C, Santa Rosa, 800-434-0222, 707-526-4108, senioradvocacyservices.org.