An older adult may experience a decline in immune function. The dysregulation of the immune system associated with aging is referred to as immune senescence.
Various theories have been proposed to explain this:
(1) vitamin D or other nutritional deficiency
(2) thymic hypoplasia and loss of memory and NK cells
(3) decline in immunoglobulin production
(4) impact of comorbid conditions such as myelodysplasia
(5) polypharmacy
Manifestations:
(1) reactivation of Herpes zoster or other previously sequestered infection
(2) poor antibody response to vaccination or rapid decline of protective antibodies
(3) appearance of tumors that may have been suppressed by an immune response
(4) opportunistic infection
(5) occurrence of an infection for which there had been previous immunity
(6) increased severity of an infection
An older adult may benefit from increasing the amount of antigen given for vaccination.
