"immunity from an Omicron infection" . "resistance" . "immunization" . . "artificially acquired immunity" . "immune systems" . "Immunity" . . . "immunologic memory" . . "immunity (medical)" . "Medical Immunity" . . "Immunity (medical)#Naturally acquired" . "Immunity_(medical)#Hybrid_immunity" . "immunities" . "immunomodulatory capacity" . "maternally derived immunity" . "acquired immunity" . "pathogen resistance" . "Immunity from an Omicron infection" . "Immunity (medical)" . "naturally acquired immunity" . "immune functions" . . "Natural immunity" . "Immunity (medical)" . . . "immune response" . "immune responses" . "immunological" . "immune" . "natura" . "immune capacity" . "immune function" . "protection" . "natural immunity" . "immunity" . "immune system" . "Immune responses" . "natural" . . "active response" .