Why over-65s succumb to flu: Their immune systems should be ‘wiser’ than younger people’s – but new study shows fighter cells start to forget everything except childhood viruses
- A team at the University of Chicago has answered a question that has puzzled many for years
- Why are the elderly more likely to die when their immune systems are ‘wiser’ than anyone else’s?
- They have found that in elderly people, their B cells (which produce virus-fighting antibodies) become less diverse
- In other words: their toolkit is pared down, and the weapons they do deploy are weaker
Scientists have identified a key reason why vaccines fail in elderly people – paving the way to better shots.
Older people are the most complicated demographic when it comes to flu.
In theory, they should be more resilient because the more flu you’re exposed to, the more intelligent your immune system is – it can recognize more enemies, and immediately be on the defensive.
But data show consistently that the elderly are more likely to die of influenza than any other group, including flu-naive children.
Now, a team at the University of Chicago has found a new piece of the puzzle that is essential to building a universal flu vaccine – something Congress has invested $1 billion in.
A team at the University of Chicago has answered a question that has puzzled many for years: why are the elderly more likely to die when their immune systems are ‘wiser’ than anyone else’s?
‘The major implication is when a newly circulating influenza virus infects elderly individuals, they don’t have quite the right tool to fight it because their antibodies are not as protective,’ said senior study author Dr Patrick Wilson, whose study is published today in the journal Cell Host and Microbe.
‘Our findings could be used by the vaccine community to make better vaccines and improve protection of the elderly population.’
The team found that while older people’s bodies may recognize viral enemies, they are not able to produce enough antibodies to protect against new mutations.
B cells are the cells in the immune system responsible for producing antibodies, which fight invaders.
Looking at people of all ages, the Chicago team found the B cells in younger people were more complex – they recognized more mutations and were able to deploy all kinds of antibodies to fight a variety of things.
In older people, their B cells had become more limited, and the antibodies they did deploy were less potent.
In a nutshell: the ‘toolkit’ needed to set up different weapons is pared down in elderly people. They could only target old strains with outdated arsenal.
And since the flu is ever-changing, a flexible and diverse immune system is key.
The findings suggest antibodies from older people arise from the memories of B cells that are generated early in life.
But the team believes there is a way to fix the ‘tool’ needed to unleash antibodies to fight the virus.
Currently, the flu shot contains traces of flu strains, which are dormant (they do not contain a ‘live’ virus that could infect). These strains change each year depending on what flu is circulating.
There are vaccines specific for older age groups – there is one for over-50s and one for over-65s.
But the Chicago team say the new federal funds should be directed at looking at driving protective mutations in B cells to improve flu immunity in the elderly.
‘More recent vaccines developed especially for the elderly population are now on the market and could help induce more protective antibodies,’ Dr Wilson said.
‘The next step will be to evaluate antibody adaptability in elderly individuals immunized with these vaccines.’