What are the requirements for a prison official to be found liable for injuries sustained by an inmate as a result of inadequate medical care?

Second, the prison official must have acted with "deliberate indifference" to a substantial risk of serious harm to the inmate. Farmer, 511 U.S. at 834. "Mere negligence is not sufficient to establish liability." Frost v. Agnos, 152 F.3d 1124, 1128 (9th Cir. 1998). Rather, a plaintiff must set forth facts to show that a defendant knew of, but disregarded, an excessive risk to inmate safety. Farmer, 511 U.S. at 837. That is, "the official must both be aware of facts from which the inference could be drawn that a substantial risk of serious harm exists, and he must also draw the inference." Id.