Ensuring Vaccination and Treatment Affordability Act This bill requires COVID-19 (i.e., coronavirus disease 2019) vaccines and treatment, as well as treatment for conditions that may complicate COVID-19 treatment, to be covered without cost-sharing under the Children's Health Insurance Program (CHIP) and Medicaid. Additionally, the bill includes vaccines for COVID-19 in the Vaccines for Children (VFC) Program. The VFC Program provides free vaccinations to individuals 18 years of age or younger who are uninsured or underinsured (i.e., with limited or no insurance for vaccines), are eligible for Medicaid, or are American Indians or Alaskan Natives.