Does adult pneumococcal (pneumonia) vaccination modify the risk of developing dementia?

From the Guidelines

Adult pneumonia vaccination may have a potential role in reducing dementia risk by preventing infections that trigger inflammatory responses in the brain, with the most recent guidelines suggesting shared clinical decision-making for PCV13 use in adults aged ≥65 years who do not have an immunocompromising condition, CSF leak, or cochlear implant 1. The standard pneumococcal vaccines for adults include Prevnar 13 (PCV13) and Pneumovax 23 (PPSV23), with recommendations typically being one dose of each for adults 65 and older, spaced at least one year apart. Some key points to consider in the context of pneumonia vaccination and dementia risk include:

• The protective mechanism likely involves preventing bacterial infections that could otherwise lead to systemic inflammation, which can damage brain tissue and accelerate cognitive decline 1.
• Preventing pneumonia helps maintain overall health and oxygen levels, indirectly supporting brain function.
• While vaccination alone cannot prevent all cases of dementia, it represents one potentially modifiable risk factor as part of a comprehensive approach to brain health that includes controlling cardiovascular risk factors, maintaining physical activity, and cognitive engagement.
• The Advisory Committee on Immunization Practices (ACIP) continues to recommend that all adults aged ≥65 years receive 1 dose of PPSV23, with PCV13 recommended on the basis of shared clinical decision-making for certain individuals in this age group 1. Key considerations for shared clinical decision-making for PCV13 use in adults aged ≥65 years include:
• The individual patient’s risk for exposure to PCV13 serotypes and the risk for pneumococcal disease as a result of underlying medical conditions.
• The potential benefits and risks of PCV13 vaccination, including the potential to reduce the risk of pneumococcal disease and the potential for adverse reactions.

From the Research

Pneumonia Vaccination and Dementia Risk

• There is no direct evidence in the provided studies to suggest that adult pneumonia vaccination modifies dementia risk.
• The studies primarily focus on the effectiveness of pneumococcal vaccines in preventing pneumococcal pneumonia and invasive pneumococcal disease in older adults 2, 3, 4, 5.
• While the studies discuss the benefits and effectiveness of pneumococcal vaccines, such as PCV13 and PPSV23, in preventing pneumococcal disease, they do not explore the relationship between pneumonia vaccination and dementia risk 6.
• Therefore, based on the available evidence, it is not possible to determine whether adult pneumonia vaccination has an impact on dementia risk.

Effectiveness of Pneumococcal Vaccines

• The studies demonstrate the effectiveness of pneumococcal vaccines in preventing pneumococcal pneumonia and invasive pneumococcal disease in older adults 2, 3, 4, 5.
• For example, a study found that sequential PCV13/PPSV23 vaccination showed the highest adjusted vaccine effectiveness of 80.3% against pneumococcal community-acquired pneumonia in adults aged 65-74 years 2.
• Another study found that PPSV23 is effective against vaccine-type invasive pneumococcal disease and vaccine-type pneumococcal pneumonia, and can lower the burden of vaccine-type pneumococcal pneumonia 3.
• However, the studies do not provide evidence on the relationship between pneumonia vaccination and dementia risk.

Limitations of the Evidence

• The available studies do not investigate the potential relationship between pneumonia vaccination and dementia risk.
• The studies focus on the effectiveness of pneumococcal vaccines in preventing pneumococcal disease, but do not explore other potential health benefits or risks of vaccination 2, 3, 6, 4, 5.
• Therefore, further research is needed to determine whether adult pneumonia vaccination has an impact on dementia risk.