The shingles vaccine may both reduce and slow down dementia. The corresponding study was published in Cell.
On September 1st 2013, Wales launched a national vaccination program in which anyone aged 79 years old on that date could receive the shingles vaccine over the following year. The cut-off date allowed researchers to compare long-term outcomes of the vaccine with negligibly older peers who had turned 80 years old slightly before September 1st.
In April 2025, researchers published a study analyzing data from those whose birthdays were within a week on either side of the eligibility cut-off point. It found that older adults who received the shingles vaccine were 20% less likely to develop dementia over the next seven years than unvaccinated peers.
In the current study, researchers conducted another analysis to investigate whether the vaccine also benefits people who already show signs of cognitive problems. They found that those who had received the shingles vaccine were less likely to be diagnosed with mild cognitive impairment over a nine-year follow-up than those who remained unvaccinated.
They also found that vaccinated individuals who had dementia at the start of the program were significantly less likely to die from dementia over a nine-year follow-up than those who did not receive the vaccine. The vaccine’s protective effects were stronger in women than in men.
The researchers still don’t know exactly how the vaccine confers protection. It also remains unknown whether a newer shingles vaccine, which uses certain proteins from the virus and is more effective at preventing shingles, affects dementia risk in a similar way.
The researchers now aim to conduct a large randomized controlled trial to offer more rigorous evidence on how the vaccine affects dementia risk and progression. They are seeking philanthropic support to fund the work.
Sources: Science Daily, LabRoots, Cell