These two vaccines may offer added protection against dementia
What's the story
A recent study has found that the shingles vaccine (Shingrix) and the respiratory syncytial virus (RSV) vaccine (Arexyv) may lower dementia risk. The research, conducted by scientists from the University of Oxford, looked at over 130,000 people in the US. It was discovered that these two vaccines are linked to a lower chance of developing dementia when compared to the annual flu shot.
Vaccine efficacy
How both vaccines affect dementia risk
The study found that participants who had only the Shingrix vaccine saw an 18% lower dementia risk within 18 months, compared to those who had just the flu shot. Those who got the RSV vaccine saw a 29% lower risk of dementia than those who had the flu shot. When both vaccines were administered together, there was a combined effect with a 37% reduction in risk. However, this was not statistically greater than one vaccine alone.
Adjuvant impact
Speculations around the AS01 adjuvant
Notably, both Shingrix and Arexyv vaccines are recommended for older adults and contain the AS01 adjuvant. This element helps boost the immune response post-vaccination. The study authors speculate that "the AS01 adjuvant itself plays a direct role in lowering dementia risk." They also note some vaccines may "protect against dementia through mechanisms unrelated to (or at least in addition to) the prevention of their [target virus]."
Immune response
Vaccines seem to significantly reduce this risk
The study's findings hint that certain vaccines could protect against dementia by activating crucial pathways in the immune system. This aligns with a growing theory that dementia is not just a brain disease but an immune disorder within the brain. In recent years, research has shown that exposure to common viruses can increase the risk of cognitive decline later on. However, vaccines seem to significantly reduce this risk.
Vaccination guidelines
Both vaccines likely offer some protection against dementia
In the US, it's generally recommended for adults over 50 to get two doses of the shingles vaccine. Adults over 75 are also advised to get the RSV vaccine. The study concludes that both AS01 shingles and RSV vaccines likely offer some protection against dementia, although the exact mechanisms behind this protection are yet to be determined. The findings were published in npj Vaccines.