ABSTRACT
BACKGROUND: Reduced response to hepatitis B vaccines is associated with aging, confounding and comorbid conditions, as well as inadvertent subcutaneous (SC) inoculation. We hypothesized that the antibody and T cell-mediated immune responses (T-CMI) of elderly adults to a vaccine intended for intramuscular (IM) administration would be attenuated when deposited into SC fat, independent of confounding conditions. RESULTS: Fifty-two healthy, community dwelling elderly adults (65-82 years), seronegative for HBV, were enrolled in the SENIEUR protocol as a strictly healthy population. These seniors were randomized to receive a licensed alum-adjuvanted recombinant HBV vaccine either SC or IM, with the inoculum site verified by imaging. The response rates, defined as hepatitis B surface antibodies (HBsAb) ≥10 IU/L, were significantly lower in the elderly than in young adults, a group of 12, healthy, 21-34-year-old volunteers. Moreover, elderly participants who received the vaccine IM were significantly more likely to be responders than those immunized SC (54% versus 16%, p = 0.008). The low seroconversion rate in the IM group progressively declined with increasing age, and responders had significantly lower HBsAb titers and limited isotype responses. Moreover, T-CMI (proliferation and cytokine production) were significantly reduced in both percentage of responders and intensity of the response for both Th1 and Th2 subsets in the elderly. CONCLUSIONS: Our data demonstrate the blunted immunogenicity of SC inoculation as measured by peak titers and response rates. Further, the qualitative and quantitative deficits in B- and T-CMI responses to primary alum adjuvanted protein antigens persisted even in strictly healthy elderly populations with verified IM placement compared to younger populations. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT04162223. Registered 14 November 2019. Retrospectively registered.
ABSTRACT
Racial differences in correlates and use of formal home and community services and in the predictive ability of the Andersen-Newman model were examined in older African American and white, community-dwelling adults. Results show greater service use by older African Americans and suggest racial differences in the correlates of service use. Racial differences in the predictive ability of the Andersen-Newman model were also evident. While approximately 78 percent of participants (82 percent of whites and 66 percent of African Americans) were correctly identified, findings regarding sensitivity and specificity suggest that much remains to be learned about factors associated with the use of formal home and community services among older adults.
