Study shows shingles vaccine could reduce risk of dementia

A study published in the scientific journal Nature Medicine suggests that the recombinant shingles vaccine may be associated with a 17% lower risk of dementia compared to the attenuated vaccine, over six years after vaccination.

The recombinant vaccine consists of the herpes zoster virus protein with the adjuvant AS01 and does not contain active virus, unlike the attenuated vaccine, which uses a weakened version of the virus. Both types of vaccines are available in Brazil.

Previous research has suggested that the live attenuated vaccine can reduce the risk of dementia, but those studies involved small sample sizes. The attenuated vaccine has been discontinued in some countries, including the United States, in favor of the recombinant vaccine, which is more effective at preventing shingles.

To see if the recombinant vaccine could have similar effects in preventing dementia, the researchers analyzed electronic health data from 103,837 people who received their first dose of the vaccine between 2017 and 2020, 95% of whom received the recombinant vaccine. The data was compared with those from previous studies of the live attenuated vaccine.

The study found that the recombinant vaccine was associated with a lower risk of dementia, with a 17% increase in time without diagnosis, equivalent to an additional 164 days without a dementia diagnosis in those who eventually developed it. Furthermore, the protective effect was 9% greater in women than in men.

The researchers also noted that both live attenuated and recombinant vaccines provide protection against dementia compared with other vaccines commonly given to older adults, such as the Tdap (tetanus, diphtheria, pertussis) vaccine and the influenza vaccine.

Despite the results, the authors stress that the study is observational and cannot prove a causal relationship between the vaccine and dementia prevention. Additional studies are needed to validate these findings.