Chronic stress modulates the immune response to a pneumococcal pneumonia vaccine

Objective: Influenza and pneumonia account fur significant morbidity and mortality, particularly in older individuals. Previous studies have shown that spousal caregivers of patients with dementia have poorer antibody and virus specific T cell responses to an influenza virus vaccine relative to noncaregiving control subjects, This study tested the hypothesis that stress can also significantly inhibit the IgG antibody response to a pneumococcal bacterial vaccine, Method: We measured antibody titers of current caregivers, former caregivers, and control subjects after vaccination with a pneumococcal bacterial vaccine. Results: Caregivers showed deficits relative to controls and former caregivers in their antibody responses to vaccination. Although the groups did not differ before vaccination or in the rise in antibody 2 weeks or 1 month after vaccination, current caregivers had lower antibody titers 3 and 6 months after vaccination than either former caregivers or controls. Conclusions: These data, the first evidence that chronic stress can inhibit the stability of the IgG antibody response to a bacterial vaccine for pneumonia, provide additional evidence of health risks associated with dementia caregiving.