Chronic stress modulates the immune response to a pneumococcal pneumonia vaccine

Objective: Influenza and pneumonia account fur significant morbidity and mo rtality, particularly in older individuals. Previous studies have shown tha t spousal caregivers of patients with dementia have poorer antibody and vir us specific T cell responses to an influenza virus vaccine relative to nonc aregiving control subjects, This study tested the hypothesis that stress ca n also significantly inhibit the IgG antibody response to a pneumococcal ba cterial vaccine, Method: We measured antibody titers of current caregivers, former caregivers, and control subjects after vaccination with a pneumococ cal bacterial vaccine. Results: Caregivers showed deficits relative to cont rols and former caregivers in their antibody responses to vaccination. Alth ough the groups did not differ before vaccination or in the rise in antibod y 2 weeks or 1 month after vaccination, current caregivers had lower antibo dy 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 vacci ne for pneumonia, provide additional evidence of health risks associated wi th dementia caregiving.