Vakzination, immune response

The human immune system with its adaptive and innate immune response is subject to a progressive aging process. The mechanisms leading to this are still incompletely understood. Further research is needed to counteract the associated adverse consequences for the elderly such as higher risk of infection as well as long-term complications and reduced response to vaccination. In this context, the changes in the innate and adaptive immune system are referred to as "immune senescence", and age-related upregulation of inflammatory processes as "inflammaging".

Immune senescence can be exemplified in zoster disease. Postherpetic neuralgia occurs mainly in this population group and shows an unpredictable course despite adequate pain therapy. The quality of life is significantly reduced. The currently available recombinant varicella zoster subunit vaccine can minimize the risk of PHN in the long term and in high percentage. Costs for the health care system can thus be saved. Further details will be presented later.

In addition to the consequences of immune senescence, the role of aging-related alterations of the lymph nodes is underestimated. Due to their fibrosis, there are negative effects on the adaptive immune response.

What are the possibilities to increase the effectiveness of vaccination in the elderly? On the one hand, by increasing the antigen concentration (tetravalent high-dose vaccine Efluelda for people aged 60 years and older with four times the antigen amount against influenza), this results in a slight but significant increase in effectiveness compared to the standard vaccine. According to STIKO, on average per influenza season could be reduced: about 23,000 physician consultations, about 300 hospitalizations and about 160 deaths. Another way to increase effectiveness is to add an adjuvant (e.g., in the zoster vaccine Shingrix), although the underlying processes of an enhanced immune response are largely unclear.

The mRNA vaccines used for the first time in SARS-CoV-2 infections (see Vaccines below) are based on the fact that the vaccinated person himself synthesizes the viral antigens against which his immune system forms protective antibodies. The protection extends primarily to the prevention of severe, fatal courses.

Factors influencing the immune response to vaccination:

Factors influencing vaccination are extremely extensive and can only be partially influenced (e.g., place of residence, time of year, family size, etc.). Of note are the coadministration of antipyretics with vaccination. Children receiving acetaminophen with vaccination have measurably lower vaccine responses to many standard vaccines and also show lower vaccine effects when boosted. Similar effects have been demonstrated for ibuprofen in adults, but here they relate only to basic immunization. Of interest are effects of statins, which in one study reduced vaccination response with trivalent influenza vaccines.