Open Enrollment for 2023 Benefits is Oct. 11 - Nov. 10, 2022

Open Enrollment is your opportunity to make/change your plan elections, add/drop dependents for the upcoming year, and change your monthly sick leave usage. Selections made during Open Enrollment will be effective January 1, 2023. You will be able to make changes October 11th through November 10th, with a January 1, 2023 effective date. 

Aetna is Replacing Blue Shield of California

Beginning January 1, 2023, the County of San Mateo will replace Blue Shield with Aetna as a medical carrier/provider. We will no longer offer any Blue Shield medical plans. We will continue to offer all current Kaiser Permanente plans.

Aetna Logo

Why Aetna?

  • Better overall premium rates resulting in cost savings for retirees and the County compared to the 2023 rates we received from Blue Shield.
  • A lower costing Aetna Value Network HMO (AVN) plan that includes the Sutter/Mills Peninsula Medical Group which replaces the Blue Shield Trio Plan
  • An HMO and/or AVN option for students and early retirees who move out-of-state with their nationwide* HMO and/or AVN HMO plan (* some states and zip code exclusions may apply)
  • A comparable Medicare Advantage PPO plan for our retiree population which will provide a 61% premium cost savings each month

For Plan Information, Resources and to Find a Provider, please visit County of San Mateo Retiree-specific Aetna website:

Aetna Online Training Webinar on Thursday October 6!

Attend an online Presentation and learn more about the Aetna Plans available to you. Join the training online from anywhere!  Admission to attend the session is on a first come first serve basis. No advance sign up is requiredTo join the webinars on October 6th, click the link below:

  • Aetna Medicare Advantage PPO Plan for Retirees 65+

2023 Retiree Benefits Guide & Rates

Open Enrollment Resources for Retirees

Visit for webinars schedule and  see resources from our Benefit Providers .

What’s New for 2023


Beginning January 1, 2023, Aetna will replace Blue Shield as a County of San Mateo medical carrier/provider. We will no longer offer any Blue Shield medical plans.

  • All current Blue Shield plan members and United Healthcare members will automatically be transferred into a similar Aetna plan on January 1, 2023 unless you complete and submit the Open Enrollment Change Form electing a new plan or make a change.
  • If you are not a current Blue Shield member or United Healthcare member and do not wish to make any changes, this change will not affect you. (NO CHANGES ARE BEING MADE TO KAISER) 
Blue Shield Plan Aetna Plan
Blue Shield HMO TRIO Aetna HMO AVN
Blue Shield PPO Aetna OAMC PPO ($200 Deductible)
Blue Shield Out-Of-State Aetna OAMC PPO ($300 Deductible)
Blue Shield Medicare Advantage PPO OR United Healthcare HMO Aetna Medicare Advantage PPO