For Aim 1, the investigators will conduct a one-year cluster randomized controlled trial of a Vaccine Acceptance Intervention versus Usual Care with randomization at the level of VA Medical Center (VAMC). Usual Care will consist of all national and local initiatives to promote COVID-19 vaccine acceptance in Veterans such as vaccine mandates, mobile clinics, outreach calls, etc. The Implementation Facilitation team will include a VISN-level external facilitator, VAMC-level internal facilitators, and clinic-level site champions to support PACT staff, Coaches and Peers in implementing the Vaccine Acceptance Intervention with unvaccinated Veterans as well as in lowering barriers to vaccine access at intervention sites. For Aim 2, the investigators will identify a diverse sample of 450 Veterans across VAMCs in VISNs 16 and 21, who have had primary care visits at Intervention and Usual Care sites, and who have either recently received (N=360) or have not received (N=90) COVID-19 vaccination. The investigators will over sample recently vaccinated Veterans to describe the impact of the Vaccine Acceptance Intervention on Veterans' decisions to accept COVID-19 vaccination in addition to over-sampling women, ethnic/racial minorities, rural and younger Veterans, and those with mental health conditions. Follow-up qualitative interviews will be conducted in a subsample to better understand factors related to recent vaccine acceptance and persistent vaccine hesitancy. Finally, for Aim 3, the investigators will conduct process and summative interviews with VA staff and providers from VAMC sites in VISNs 16 and 21 with high and low vaccination rates) to learn which implementation strategies were most and least effective.