Immunosenescence: implications for vaccination programs in the elderly

Abstract

Worldwide, infectious disease is responsible for much of the morbidity and mortality in the elderly. As the number of individuals over the age of 65 increases, the economic and social costs of treating these infections will become a major challenge. Vaccination is the most effective and least costly preventative measure in our arsenal; however, vaccines that are effective in children and young adults are often ineffective in older adults. This is a result of the deterioration in immune function that occurs with age, referred to as immunosenescence. Age-associated changes in leukocyte phenotype and function impair primary vaccine responses and weaken long-lasting memory responses. In this review, we discuss current vaccination approaches in the elderly and strategies to improve responsiveness in older adults, which include increasing vaccine immunogenicity and overcoming the fundamental immune defects that prevent optimal immune responses.

Adjuvant Effect of Orally Applied Preparations Containing Non-Digestible Polysaccharides on Influenza Vaccination in Healthy Seniors: A Double-Blind, Randomised, Controlled Pilot Trial

“…The process of ageing is associated with a deterioration in the function of the immune system, referred to as immunosenescence [ 1 ]. As a consequence of impaired immune responses, the elderly are highly susceptible to infection and have an increased risk of complications resulting in hospitalisation and mortality [ 1 , 2 ]. Although vaccination is considered the most effective measure to prevent or reduce the severity of infections and their associated complications [ 2 ], the response to vaccination in the elderly has been found to be considerably weaker than in younger adults, due to immunosenescence [ 3 ].…”

“…As a consequence of impaired immune responses, the elderly are highly susceptible to infection and have an increased risk of complications resulting in hospitalisation and mortality [ 1 , 2 ]. Although vaccination is considered the most effective measure to prevent or reduce the severity of infections and their associated complications [ 2 ], the response to vaccination in the elderly has been found to be considerably weaker than in younger adults, due to immunosenescence [ 3 ]. To improve protection against infectious diseases in the elderly, there is a need for novel strategies to boost the immune response [ 4 ].…”

Study of the Immune Response in the Elderly: Is It Necessary to Develop a Vaccine againstNeisseria meningitidisfor the Aged?

“…Few vaccines are recommended to the elderly, such as influenza, herpes zoster, diphtheria, tetanus, pertussis, hepatitis, and pneumococcal vaccines [11]; however, these vaccines are less effective in the aged population than in the young [19].…”

“…When evaluated separately, T cell subsets show a reduction of two- to fivefold in the number of naive T cells in healthy elderly individuals [10]. Also, naive T cells of the elderly present decreased cytokine production, less clonal expansion, and decreased expression of activation markers after the primary antigen presentation by antigen-presenting cells (APCs) [11].…”

“…The intrinsic defects of B cells related to aging include a decrease in the expression of activation-induced cytidine deaminase (AID) and a decreased number of switched memory B cells [1]. This leads to the production of short-lived, low-affinity antibodies that may have defects in isotype switching, reflecting a low ability to respond effectively against pathogens [11].…”