Response to Vaccination in Dementia Caregivers: A Test of Cognitive Vulnerability and Resilience

According to the most recent epidemiological data, infectious diseases such as pneumonia, influenza, and septicemia are among the leading causes of death in older adults in the United States. Because the immune system becomes less responsive with age, older adults may be particularly vulnerable to mutating pathogens such as influenza which present novel antigens each year. However, immunological memory can be created through immunization, and this can be an effective compensation for immunosenescence. The ability of the aging immune system to respond to novel antigens, including immunizations, may also be affected by psychosocial factors. Among older adults, caregiving appears to create both psychiatric and immunological vulnerability. However, cognitive theory states that negative consequences do not arise from a stressful event but rather from the cognitive appraisal, interpretation, and processing ofthe event. Cognitive factors can promote vulnerability when events are interpreted as threatening, focus is on potential negative outcomes, and processing is uncontrolled and intrusive. Conversely, cognitive factors can promote resilience when events are interpreted as challenging, focus is on positive aspects of the situation, and processing is controlled, deliberate, and mindful. Beginning at the time of diagnosis, this study will follow spouses of patients with non-treatable dementias such as Alzheimer's disease (n=75) and demographically matched controls (n=75). On entry into the study, personality measures and psychiatric history will be obtained. Every six months, participants will provide measures of cognitive processing, depression, and salivary cortisol. They will be vaccinated annually against influenza using trivalent vaccine; antibody titers following vaccination will be assessed. It is expected that caregivers will have higher rates of depression, more dysregulated cortisol production, and lower antibody titers, but that cognitive factors will play an important role in increasing or decreasing vulnerability to all of these consequences. Given that it is usually impossible to cure dementia and difficult to ask a spouse to abandon caregiving, it is important to identify factors associated with caregiver vulnerability and resilience that also offer the possibility of intervention.