Despite being exposed to a lifetime of illnesses, immune systems in the elderly are worse than fighting stealthy, shape-shifting viruses like the flu
Why aging decreases our immune system's abilities has been a mystery to researchers. But a new study published in Cell Host & Microbe finds that our infection-battling B-cells become blunted with age, making us less equipped to fight off the flu and other illnesses in our advanced years. And because most vaccines rely on a cellular response to work, the finding may explain why the influenza vaccine is less effective in this population.
New Mutations, Old Tools
A research team compared how B cells and antibodies from younger adults (ages 22 to 64) and elderly adults (ages 71
Our immune systems learn from exposure, and B-cells play a major role in the immunity process. With the help of other cells in the immune system, B cells release cells when we get sick or receive immunization. Antibodies are Y-shaped proteins that bind to harmful invaders and mark them for destruction. Once the infection has been cleared, a type of record-keeping B-cell, known as memory B-cells, remain in the bloodstream and stand ready to produce antibodies if the threat is encountered again.
immune system's ability to produce more powerful antibodies in response to infections. Immune Imprinting
While new flu strains are being used, mostly on memory B cells to make immune responses that are ill-equipped to squash rapidly evolving pathogens like the flu virus. Threw the elderly participant's B cells for a loop, they were very proficient at combatting mutations of the virus that circulated during their childhoods. Young people's B-cells, however, struggled when faced with older strains of the flu.
Although each person's timeline is different, the strength of our immune response diminishes over time once we hit a certain age. The researchers observed that between 50 and 70-year-olds had intermediate declines in their influenza-fighting power, with steeper drops typical after age 70.
That's why vaccines are so necessary for the elderly. But because of the ever-changing flu virus, it is capable of developing young and old immune systems, even a well-matched vaccine can only reduce the chances of illness by 40 to 60 percent in the general population. Effective rates are typically less for the elderly, but Wilson stressed that "not as effective" does not mean "not at all effective."
"Vaccination still helps if not effective with age," he said. “With vaccination, the duration and severity of illness will be reduced, which is extremely important for older people as the severity of infection is already much worse.”
As the research community toils towards a universal flu vaccine that would provide lifetime immunity , there have been advancements in the interim. New high-dose flu vaccines for older adults are now available and can have more protective antibodies.