Glucocorticoid dosing and implications for vaccination: Evolution of global definitions.

Despite widespread adoption of "high-dose" glucocorticoid definitions across international immunisation guidelines (i.e., prednisone-equivalent dosing >20 mg/day, or >2 mg/kg/day in children), the rationale remains unclear. Literature searches were performed through academic databases for this narrative review to identify relevant evidence regarding glucocorticoid dosing on vaccine responses and safety. In people receiving prednisone <7 mg/day, vaccine responses are maintained. In people on 'high-dose' glucocorticoids (>20 mg/day), antibody titres and seropositivity are reduced, whereas the impact of low- to medium-dose glucocorticoids (7 to 20 mg/day) on vaccine efficacy remains inconclusive. Due to inconsistent paediatric dosing regimens, data is insufficient to support a unified "high-dose" glucocorticoid threshold. Non-live vaccines are well tolerated in patients receiving glucocorticoids with rheumatic/inflammatory disorders, but enhanced reactogenicity after live vaccination may occur in those with severe immunodeficiencies. Clinicians should consider individual risk-benefit profiles, rather than following strict dosing thresholds, when curating immunisation programs for patients prescribed glucocorticoids.