Fortunately, there are vaccines that can protect against some age-related disease.
Among them are:

Pneumococcal vaccine
The Pneumococcus bacterium (Streptococcus pneumoniae) is the major cause of bacterial pneumonia. It can be lethal in older adults (and in some younger ones as well). Pneumococcus is called an encapsulated organism, and such organisms can be filtered out of the bloodstream by the spleen. The pneumococcal vaccine protects against 23 different forms of pneumococcus. When it was first used, it covered fewer subtypes and its protection was thought to be lifelong. We know now that the duration of protection by that vaccine is more limited, and older adults at particular risk should be revaccinated. Those at particular risk include those with diabetes and other chronic illnesses that can reduce the immune response.

Influenza vaccine
Influenza (the flu) is caused by a virus. How deadly the flu virus is depends on what strain is passing through a population in a given year, and the immune strength of those who contract the illness. The most infamous influenza outbreak occurred in 1918, and killed somewhere between 20 and 40 million people worldwide.

There is a vaccine that is protective against the influenza virus. The flu vaccine is an annual vaccination. That is, the vaccine is developed each year in response to the variant of the virus that has arisen for that year; thus, that vaccine needs to be given every year.

Tetanus
Tetanus is a bacterial infection that is deadly, and especially in older adults. The vaccine against tetanus is given in multiple doses in infancy, with boosters given about every ten years in adults. It is important for older adults to remain up to date on tetanus vaccinations, since loss of sensation in the feet, as with diabetes or poor circulation, can mean that a dirty wound may go unnoticed, increasing the risk for the tetanus bacterium to penetrate broken skin.