Sunscreen applied at ≥ 2 mg cm⁻²during a sunny holiday prevents erythema, a biomarker of ultraviolet radiation‐induced<scp>DNA</scp>damage and suppression of acquired immunity

Optimal sunscreen use prevents erythema during a sunny holiday. Erythema predicts suppression of CHS (implying a shared action spectrum). Given that erythema and CPDs share action spectra, the data strongly suggest that optimal sunscreen use will also reduce CPD formation and UVR-induced immunosuppression.