Sara van den Berg

106 Chapter 4 In conclusion, identification of the driving forces that induce age-related changes in the immune system is important to protect the growing population of older adults against infectious diseases. Especially influenza leads to more increased disease burden in older adults, e.g. severe symptoms and higher risk of complications, hospitalization and mortality. Our study shows that despite the lower frequency of influenza virus-specific memory T-cell responses in older adults, CMV infection does not seem to impair the T-cell response against acute influenza virus infection. This work supports the view that CMV acts as an immune modulatory mediator, rather than having a negative impact on the immune system.