Vaccines are one of medicine’s most powerful weapons against the spread of infectious diseases— but could their protection extend beyond the specific virus or bacteria they’re designed to block?
Mounting evidence suggests certain jabs given every year in the UK may also reduce the risk of seemingly unrelated illnesses, from ear infections to strokes.
Last month, scientists from Saint Louis University School of Medicine in the U.S. released a study which showed that getting the flu vaccine every winter for several consecutive years could significantly reduce the risk of dementia.
They tracked nearly 70,000 people aged over 60 and found that once people had been vaccinated for six years or more, their dementia risk dropped by an average of 14 per cent.
One theory is that repeated annual jabs gradually strengthen the ageing immune system to the point where it can prevent, or even repair, the underlying damage in the brain that causes dementia.
Vaccines are one of medicine’s most powerful weapons against the spread of infectious diseases— but could their protection extend beyond the specific virus or bacteria they’re designed to block? A woman is pictured getting her booster jab in September
This benefit probably comes from regular exposure to any type of vaccine, not just the flu one, later in life, when the risk of dementia is greatest.
Studies suggest that pneumonia jabs given to those over 65, or with chronic conditions that affect the heart, lungs, liver or kidneys, also reduce the risk of dementia by firing up the immune system enough to halt the damage to the brain.
A study by Duke University in the U.S., presented last year at the Alzheimer’s Association International Conference, showed that those aged over 65 who had the pneumonia jab were up to 30 per cent less likely to develop Alzheimer’s than those not vaccinated.
Animal research shows that vaccines increase the activity of microglia, cells in the central nervous system that remove damaged nerve cells from the brain.
One study by scientists in China, published in the Journal of Neuroinflammation in 2020, also found that injecting the flu vaccine into mice in the early stages of Alzheimer’s removed amyloid beta — the harmful deposits of protein thought to cause symptoms such as memory loss, confusion and agitation — from the brain.
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