Faculty Bibliography

We evaluated whether coadministration of the yellow fever (YF) virus vaccine with human immunoglobulin (Ig) that contained YF virus-neutralizing antibodies would reduce post-vaccination viremia without compromising immunogenicity and thus, potentially mitigate YF vaccine-associated adverse events. We randomized 80 participants to receive either YF vaccine and Ig or YF vaccine and saline placebo. Participants were followed for 91 days for safety and assessments of viremia and immunogenicity. There were no differences found between the two groups in the proportion of vaccinated participants who developed viremia, seroconversion, cluster of differentiation (CD)-8(+) and CD4(+) T-cell responses, and cytokine responses. These results argue against one putative explanation for the increased reporting of YF vaccine side effects in recent years (i.e., a change in travel clinic practice after 1996 when hepatitis A prophylaxis with vaccine replaced routine use of pre-travel Ig, thus potentially removing an incidental YF vaccine-attenuating effect of anti-YF virus antibodies present in Ig).

HIV and hepatitis B virus co-infection leads to substantially increased morbidity and mortality compared with either infection alone. Immunisation with hepatitis B virus vaccine is the most effective way to prevent the infection in people with HIV; however, these patients have decreased vaccine responses and a short duration of protection compared with immunocompetent individuals. Control of HIV replication with highly active antiretroviral therapy and increased CD4 cell counts are associated with improved immune responses to hepatitis B vaccination. New vaccination strategies, such as increased vaccine dose, use of the intradermal route, and addition of adjuvants, could improve response rates in adults with HIV.

The duration of anti-yellow fever (YF) virus immunoglobulin M (IgM) antibodies following YF vaccination is unknown, making it difficult to interpret positive IgM antibody results in previously vaccinated travelers. We evaluated the frequency and predictors of YF IgM antibody positivity 3-4 years following YF vaccination. Twenty-nine (73%) of 40 participants had YF IgM antibodies 3-4 years postvaccination. No demographic or exposure variables were predictive of YF IgM positivity. However, persons who were YF IgM positive at 3-4 years postvaccination had earlier onset viremia and higher neutralizing antibody geometric mean titers at 1 month and 3-4 years postvaccination compared with persons who were YF IgM negative. Detection of YF IgM antibodies several years postvaccination might reflect remote YF vaccination rather than recent YF vaccination or YF virus infection.

BACKGROUND:Adjuvanted vaccines have the potential to improve influenza pandemic response. AS03 adjuvant has been shown to enhance the immune response to inactivated influenza vaccines. METHODS:This trial was designed to evaluate the immunogenicity and safety of an inactivated 2009 H1N1 influenza vaccine at varying dosages of hemagglutinin with and without extemporaneously mixed AS03 adjuvant system in adults ≥ 18 years of age. Adults were randomized to receive 2 doses of 1 of 5 vaccine formulations (3.75 µg, 7.5 µg, or 15 µg with AS03 or 7.5 µg or 15 µg without adjuvant). RESULTS:The study population included 544 persons <65 years of age and 245 persons ≥ 65 years of age. Local adverse events tended to be more frequent in the adjuvanted vaccine groups, but severe reactions were uncommon. In both age groups, hemagglutination inhibition antibody geometric mean titers after dose one were higher in the adjuvanted groups, compared with the 15 µg unadjuvanted group, and this difference was statistically significant for the comparison of the 15 µg adjuvanted group with the 15 µg unadjuvanted group. CONCLUSIONS:AS03 adjuvant system improves the immune response to inactivated 2009 H1N1 influenza vaccine in both younger and older adults and is generally well tolerated. ClinicalTrials.gov NCT00963157.

BACKGROUND:Vitamin D deficiency is common in HIV-infected individuals. In adults, traditional and HIV-related factors play a role in vitamin D status, and deficiency appears to impair immune restoration and exacerbate HIV complications, like cardiovascular disease (CVD). This study sought to determine factors contributing to vitamin D status in HIV-infected youth and investigate the relationship with CVD risk, inflammation and immune restoration. METHODS:HIV-infected subjects (1-25 years old) were enrolled prospectively along with healthy controls that were group-matched by age, sex and race. HIV data were collected for the HIV-infected group, while traditional risk factors, including vitamin D intake, sun exposure, skin pigmentation, physical activity level and body mass index (BMI) were collected for both groups. Fasting lipids, plasma 25-hydroxyvitamin D (25[OH]D), and inflammation markers were measured. RESULTS:In total, 200 HIV-infected subjects and 50 controls were enrolled. HIV group had 53% male, 95% Black and a mean age of 17.2 ±4.6 years. There was no difference in 25(OH)D between groups; 77% of HIV+ and 74% of controls had 25(OH)D<20 ng/ml. Only Fitzpatrick skin type was independently associated with 25(OH)D. No HIV variables were associated with 25(OH)D, even when HIV sub-populations were examined. Inflammation, CVD risk factors and immune restoration were not independently associated with 25(OH)D. CONCLUSIONS:Vitamin D deficiency is common among HIV-infected youth. However, HIV factors, CVD risk, inflammation and immune restoration do not appear to have the same relationship with vitamin D as has been shown in adults. Supplementation trials are needed to determine if increasing 25(OH)D concentrations could better elucidate these relationships.

BACKGROUND:The current US national stockpile of influenza H5 vaccine was produced using the antigen from the strain A/Vietnam/1203/2004 (a clade 1 H5 virus). Recent H5 disease has been caused by antigenically divergent H5 viruses, including A/Indonesia/05/2005 (a clade 2 H5 virus). METHODS:The influence of schedule on the antibody response to 2 doses of H5 vaccines (one a clade 1 hemagglutinin protein [HA] vaccine and one a clade 2 HA vaccine) containing 90 μg of antigen was evaluated in healthy adults 18-49 years of age. RESULTS:Two doses of vaccine were required to induce antibody titers ≥ 1:10 in most subjects. Accelerated schedules were immunogenic, and antibody developed after vaccinations on days 0 and 7, 0 and 14, and 0 and 28, with the day 0 and 7 schedule inducing lower titers than those induced with the other schedules. With mixed vaccine schedules of clade 1 followed by clade 2 vaccine administration, the first vaccination primed for a heterologous boost. The heterologous response was improved when the second vaccination was given 6 months after the first, compared with the response when the second vaccination was given after an interval of 1 month. CONCLUSIONS:An accelerated vaccine schedule of injections administered at days 0 and 14 was as immunogenic as a vaccine schedule of injections at days 0 and 28, but both schedules were inferior to a vaccine schedule of injections administered at 0 and 6 months for priming for heterologous vaccine boosting. Clinical Trial Registry Number: NCT00703053.

The 2009 pandemic H1N1 influenza pandemic demonstrated the global health threat of reassortant influenza strains. Herein, we report a detailed analysis of plasmablast and monoclonal antibody responses induced by pandemic H1N1 infection in humans. Unlike antibodies elicited by annual influenza vaccinations, most neutralizing antibodies induced by pandemic H1N1 infection were broadly cross-reactive against epitopes in the hemagglutinin (HA) stalk and head domain of multiple influenza strains. The antibodies were from cells that had undergone extensive affinity maturation. Based on these observations, we postulate that the plasmablasts producing these broadly neutralizing antibodies were predominantly derived from activated memory B cells specific for epitopes conserved in several influenza strains. Consequently, most neutralizing antibodies were broadly reactive against divergent H1N1 and H5N1 influenza strains. This suggests that a pan-influenza vaccine may be possible, given the right immunogen. Antibodies generated potently protected and rescued mice from lethal challenge with pandemic H1N1 or antigenically distinct influenza strains, making them excellent therapeutic candidates.

OBJECTIVE: This study examines whether men-who-have-sex-with-men (MSM) and transgender (TG) persons' attitudes, beliefs, and risk perceptions toward human immunodeficiency virus (HIV) vaccine research have been altered as a result of the negative findings from a phase 2B HIV vaccine study. DESIGN: We conducted a cross-sectional survey among MSM and TG persons (N = 176) recruited from community settings in Atlanta from 2007 to 2008. The first group was recruited during an active phase 2B HIV vaccine trial in which a candidate vaccine was being evaluated (the "Step Study"), and the second group was recruited after product futility was widely reported in the media. METHODS: Descriptive statistics, t tests, and chi-square tests were conducted to ascertain differences between the groups, and ordinal logistic regressions examined the influences of the above-mentioned factors on a critical outcome, future HIV vaccine study participation. The ordinal regression outcomes evaluated the influences on disinclination, neutrality, and inclination to study participation. RESULTS: Behavioral outcomes such as future recruitment, event attendance, study promotion, and community mobilization did not reveal any differences in participants' intentions between the groups. However, we observed greater interest in HIV vaccine study screening (t = 1.07, P < 0.05) and enrollment (t = 1.15, P < 0.05) following negative vaccine findings. Means on perceptions, attitudes, and beliefs did not differ between the groups. Before this development, only beliefs exhibited a strong relationship on the enrollment intention (β = 2.166, P = 0.002). However, the effect disappeared following negative trial results, with the positive assessment of the study-site perceptions being the only significant contributing factor on enrollment intentions (β = 1.369, P = 0.011). CONCLUSION: Findings show greater enrollment intention among this population in the wake of negative efficacy findings from the Step Study. The resolve of this community to find an HIV vaccine is evident. Moreover, any exposure to information disseminated in the public arena did not appear to negatively influence the potential for future participation in HIV vaccine studies among this population. The results suggest that subsequent studies testing candidate vaccines could be conducted in this population.

In the United States, the number and proportion of HIV/AIDS cases among black/African Americans continue to highlight the need for new biomedical prevention interventions, including an HIV vaccine, microbicide, or new antiretroviral (ARV) prevention strategies such as pre-exposure prophylaxis (PrEP) to complement existing condom usage, harm reduction methods, and behavioral change strategies to stem the HIV epidemic. Although black/African Americans are disproportionately impacted by HIV/AIDS, their participation in HIV clinical research continues to have unique challenges. We theorize that interaction among multilevel factors creates ideal alignment for minority participation in HIV clinical studies. Thus, we initially set out to test an extended model of reasoned action with 362 participants to understand the interplay of sociopsychological and network-level considerations influencing minority participation in HIV prevention research efforts. In this study, we linked the intrapersonal dimensions of attitudes, beliefs, and normative concerns to community-level components, appraisal of involvement with the clinical research organization, an entity which operates within a networked structure of community partner agencies, and identification with coalition advocacy aims. Various participatory outcomes were explored including involvement in future HIV vaccine community functions, participation in community promotion of HIV vaccine research, and community mobilization. Three-stage least squares estimates indicated similar findings across three models. Significant effects demonstrate the importance of positive attitudes toward HIV vaccine research, favorable health research beliefs, perceived social support for participation, HIV/AIDS issue engagement, and perceived relevance of the clinical research site's mission and values. Identification of these nuanced pathway effects provides implications for tailored community program development.