We finally know why vaccines are less effective with age.

This is a problem healthcare professionals would rather avoid. Vaccines tend to be less effective in older people, yet they are the ones who most need protection against disease. While doctors had long observed this phenomenon, they didn't understand why seniors showed a less effective response to vaccines. For the first time, a major study reveals what happens in the bodies of older adults. This crucial discovery should lead to the development of more effective vaccines specifically designed for seniors.

With age, a whole host of changes occur in the body. And the immune system is no exception. In particular, T lymphocytes, a type of white blood cell responsible for protecting us from external threats. The mission of T lymphocytes is to " to train "other cells, B lymphocytes, to produce antibodies. But with age, these " coaches "Our immune system eventually becomes fatigued." Certain epigenetic changes – related to gene expression – alter how they respond to a threat.