In the coronavirus pandemic, older people are particularly at risk from severe courses of COVID-19. However, other infectious diseases also affect them more than younger people. On the occasion of the International Day of Older People on 1 October, Prof Luka Cicin-Sain, Head of the Department „Viral Immunology“ at Helmholtz Centre for Infection Research (HZI) in Braunschweig, talks about the ageing of the immune system.