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?
There is growing evidence that certain shots given annually in the UK could reduce the chance of strokes and ear infections.
Scientists from Saint Louis University School of Medicine released last month a study that showed getting flu shots every year for multiple years consecutively could reduce your risk of developing dementia.
Nearly 70,000 older people were tracked and they found that people who had been immunized for at least six years saw a drop in their risk of developing dementia.
It is believed that the repeated, annual injections of immunoglobulin can strengthen the body’s immune system, allowing it to prevent or repair any damage in the brain which could lead to 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? In September, a woman gets her booster vaccine.
It is possible that this benefit comes from regular, non-flu vaccine exposure later in life.
According to studies, pneumonia jabs for people older than 65 and those suffering from chronic diseases such as the liver, heart or kidneys can also lower the chance of developing dementia. The immune system is activated enough to prevent brain damage.
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.
Research in animals has shown that vaccinations can increase activity of microglia cells, which are cells within the central nervous system responsible for removing damaged nerve cells.
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.
This phenomenon, where vaccines lower the likelihood of seemingly unrelated diseases isn’t new, has been around for a while. BCG, a vaccine that was given in 14 years to UK children to fight tuberculosis and has been around for more than 40 year is also used to treat bladder cancer.
It’s given to prevent tumours recurring after surgery and works in more than two-thirds of cases. Put directly into the bladder via a catheter, it ‘turns on’ local immune system cells which attack and destroy any lingering cancer cells.
Study results show that those who are over 65 years old or have chronic conditions like the liver, kidneys or heart can reduce their risk of developing dementia. The immune system is activated enough to prevent brain damage from occurring and the pneumonia jabs help to lower the risk.
BCG is a ‘live’ vaccine, containing weakened traces of the bacterium itself, whereas the majority of UK vaccines are ‘inactivated’ — made with bacteria or viruses that have been killed.
Live vaccines such as the MMR (measles, meumps, and rubella) jab put all of the immune system on alert. This is in contrast to the case with inactivated vaccines which only activate certain parts. It means that the immune system has a greater tendency to attack foreign cells, such as cancer cells.
Jabs can have a wider range of benefits.
Everybody aged 70-79 should receive the shingles vaccination. This vaccine has been shown by studies to decrease the likelihood of suffering a stroke.
A 2017 University of Padova study in Italy revealed that yellow fever vaccinations are recommended to travelers to Trinidad, Africa, and other parts of the Americas. It also reduces the chance of developing breast cancer.
Researchers monitored the cancer rate in over 12,000 patients who received the vaccine. The vaccine could suppress inflammation and promote tumour growth. It may also block the development of blood vessels necessary to nourish a tumor.
‘Sometimes, there is a fairly straightforward explanation for why vaccines protect against other illnesses,’ says Dr Andrew Easton, a virologist at the University of Warwick.
He adds: ‘With respiratory infections such as pneumonia, there is a high risk of developing a secondary infection in the ears because bacteria there take advantage of the immune system already being under attack.’
A Shingles jab may prevent strokes because people infected by varicella-zoster virus (which causes chickenpox and shingles) are four times more likely than others to have a brain clot.
The inflammation may occur in small blood vessels located in the brain. ‘So if you are vaccinated against shingles later in life, you may well reduce your risk of stroke as well,’ adds Dr Easton.