Maryam Sadri
1,2 
, Sama Sadri
3, Hossein Khorramdelazad
4,5, Mohammad Reza Bolouri
1,2, Ahmad Vosughi Motlagh
6* 1 Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
2 Immunology Research Center (IRC), Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran
3 Department of Immunology, School of Medicine, Shahed University of Medical Sciences, Tehran, Iran
4 Molecular Medicine Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Science, Rafsanjan, Iran
5 Department of Immunology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
6 Department of Pediatrics, North Khorasan University of Medical Sciences, Bojnurd, Iran
Abstract
The immune system weakens with age through immunosenescence, making older adults more vulnerable to infections and cancers. Viral pandemics like COVID-19 hit this group hardest, with the elderly facing the highest infection and death rates, especially those with underlying conditions. With the global older population expected to double by 2050, future outbreaks will continue to target this age group. Recent vaccine research shows that aging alters immune responses in complex ways. While older individuals may produce similar levels of neutralizing antibodies after repeated vaccination, other protective functions, like antibody-dependent cellular cytotoxicity, decline significantly. The broad immunity that defends against multiple virus strains also appears impaired in the elderly. Given these findings and the limitations of herd immunity strategies, strengthening elderly immune systems through proper nutrition, healthy lifestyles, and tailored vaccination approaches is critical. Standard vaccines may not be enough. Designing vaccines and schedules specifically to overcome aging-related immune weaknesses should be a priority for protecting this growing population against future pandemics.