A mattress system includes a core mattress and a mattress cover. The core is made from a resilient material with a top surface that may be inclined with respect to the bottom surface. The removable mattress sheet covers the core and includes a breathable material that forms a hammock over a depression in the top surface. The subject rests at least partially on the hammock. One or more sidewalls of the mattress depression may have one or more openings to facilitate air circulation within the depression. The external ends of the openings may connect to an air or aerosol source to inject air or aerosols into the depression cavity. The core may be coated with a fire retardant, impermeable water-proofing or gas impermeable layer. A ventilator may be adapted within the mattress.