An argument could be made that vaccines with EUA approval cannot be mandated, while vaccines with full FDA approval may be mandated. No court, however, has interpreted this distinction.
In certain emergencies, the FDA can issue an EUA to provide access to medical products that may potentially be used when there are no adequate, approved, and available options. Under an EUA, in an emergency, the FDA makes a product available to the public based on the best available evidence, without waiting for all the evidence that would be needed for full FDA approval. EUAs are effective until the emergency declaration ends.