Throughout the COVID-19 pandemic, charges related to vaccine administration and monoclonal antibodies for Medicare Advantage (Plan C) patients were sent directly to Medicare, rather than the Plan C administrator.
Beginning with the dates of service January 1, 2022, and forward, all of these charges need to be submitted to the patient's Part C plan.
Additional details can be found on the CMS website: https://www.cms.gov/medicare/covid-19/medicare-billing-covid-19-vaccine-shot-administration.