Routine Vaccination in HIV-Infected Adults

A randomized phase II trial to compare safety and immunogenicity of the MVA-BN smallpox vaccine at various doses in adults with a history of AIDS

Traditional replicating smallpox vaccines are associated with serious safety concerns in the general population and are contraindicated in immunocompromised individuals. However, this very population remains at greatest risk for severe complications following viral infections, making vaccine prevention particularly relevant. MVA-BN was developed as a non-replicating smallpox vaccine that is potentially safer for people who are immunocompromised. In this phase II trial, 3 MVA-BN dosing regimens were evaluated for safety, tolerability, and immunogenicity in persons with HIV (PWH) who had a history of AIDS. Following randomization, 87 participants who were predominately male and African American received either 2 standard doses on weeks 0 and 4 in the standard dose (SD) group (N = 27), 2 double-standard doses on the same schedule in the double dose (DD) group (N = 29), or 3 standard doses on weeks 0, 4 and 12 in the booster dose (BD) group (N = 31). No safety concerns were identified, and injection site pain was the most commonly reported solicited adverse event (AE) in all groups (66.7%), with no meaningful differences between groups. The incidence of severe (Grade 3) AEs was low across groups and no serious AEs or AEs of special interest considered related to study vaccine were reported. Doubling the standard MVA-BN dose had no significant effect on induction of neutralizing antibodies, with 100% seroconversion and comparable GMTs at week 6 in the SD and DD groups (78.9 and 100.3, respectively). A booster dose significantly increased peak neutralizing titers in the BD group (GMT: 281.1), which remained elevated at 12 months (GMT: 45.3) compared to the SD (GMT: 6.2) and DD (GMT: 10.6) groups. However, based on the immune response previously reported for healthy participants, a third dose (booster) does not appear necessary, even for immunocompromised participants. Clinical Trial Registry Number: NCT02038881.

Safety and Immunogenicity of Modified Vaccinia Ankara-Bavarian Nordic Smallpox Vaccine in Vaccinia-Naive and Experienced Human Immunodeficiency Virus-Infected Individuals: An Open-Label, Controlled Clinical Phase II Trial

Background.  First- and second-generation smallpox vaccines are contraindicated in individuals infected with human immunodeficiency virus (HIV). A new smallpox vaccine is needed to protect this population in the context of biodefense preparedness. The focus of this study was to compare the safety and immunogenicity of a replication-deficient, highly attenuated smallpox vaccine modified vaccinia Ankara (MVA) in HIV-infected and healthy subjects. Methods.  An open-label, controlled Phase II trial was conducted at 36 centers in the United States and Puerto Rico for HIV-infected and healthy subjects. Subjects received 2 doses of MVA administered 4 weeks apart. Safety was evaluated by assessment of adverse events, focused physical exams, electrocardiogram recordings, and safety laboratories. Immune responses were assessed using enzyme-linked immunosorbent assay (ELISA) and a plaque reduction neutralization test (PRNT). Results.  Five hundred seventy-nine subjects were vaccinated at least once and had data available for analysis. Rates of ELISA seropositivity were comparably high in vaccinia-naive healthy and HIV-infected subjects, whereas PRNT seropositivity rates were higher in healthy compared with HIV-infected subjects. Modified vaccinia Ankara was safe and well tolerated with no adverse impact on viral load or CD4 counts. There were no cases of myo-/pericarditis reported. Conclusions.  Modified vaccinia Ankara was safe and immunogenic in subjects infected with HIV and represents a promising smallpox vaccine candidate for use in immunocompromised populations.

Long-term safety and serologic response to measles, mumps, and rubella vaccination in HIV-1 infected adults

We analyzed HIV viral load (VL) and CD4 count changes, and antibody responses following MMR vaccination of individuals in the U.S. Military HIV Natural History Study cohort. Cases receiving at least one dose of MMR vaccine after HIV diagnosis were matched 1:2 to HIV-positive controls not receiving the vaccine. Baseline was defined as time of vaccination for cases and indexed and matched to the time post-HIV diagnosis for controls. Changes in CD4 count and VL at 6, 12, 18 and 24 months were compared between cases and controls using a general linear model. Available sera from cases were tested for MMR seropositivity at baseline and post-vaccination at 6, 12, 18, and 24 months. Overall mean CD4 count change from baseline through 24 months was 20 (±23) cells/μL greater for cases than controls (p=0.39). Similar non-significant changes in CD4 cell count were seen in the subset of those not on HAART at baseline. VL changes were small and similar between groups (mean differential change -0.04 (±0.18) log(10) copies/mL; p=0.84). Of 21 vaccinated participants with baseline serologic testing, 14 (67%) were reactive to measles, 19 (91%) to mumps, and 20 (95%) to rubella. Three (43%) of 7 participants nonreactive to measles developed measles IgG; for mumps, 1 (50%) of 2 developed mumps IgG; for rubella, 1 (100%) developed rubella IgG. MMR vaccination did not result in detrimental immunologic or virologic changes through 24 months post-vaccination.

Hepatitis B vaccination and risk of hepatitis B infection in HIV-infected individuals

OBJECTIVE

To assess the association of hepatitis B virus (HBV) vaccination with risk of HBV infection among HIV-infected patients and HBV infection risk factors among vaccinees.

DESIGN

Observational cohort study.

METHODS

Participants enrolled from 1986 through 2004, unvaccinated and serologically negative for HBV infection at the time of HIV diagnosis, were followed longitudinally through 2007 for the occurrence of HBV infection. Risk factors for HBV infection were evaluated using time to event methods, including Kaplan-Meier survival curves and Cox proportional hazards models.

RESULTS

During 11 632 person-years of follow-up, the rate of HBV infection was 2.01 (95% CI 1.75-2.27)/100 person-years. Receipt of at least one dose of vaccine was not associated with reduced risk of HBV (unadjusted hazard ratio 0.86, 95% CI 0.7-1.1; adjusted hazard ratio 1.08, 95% CI 0.8-1.4). Receipt of three or more doses of vaccine was also not associated with reduced risk (hazard ratio 0.96; 95% CI 0.56-1.64). Among 409 vaccinees with HBsAb less than 10 IU/l, 46 (11.2%) developed HBV infection compared with 11 of 217 (5.1%) vaccinees with HBsAb > or =10 IU/l (hazard ratio 0.51; 95% CI 0.3-1.0). In participants with initial HBsAb less than 10 IU/l, 16 of 46 (35%) infections were chronic, compared with none of 11 in those with initial HBsAb at least 10 IU/l (P = 0.02).

CONCLUSION

Overall, HBV vaccination was not associated with reduced risk of HBV infection in our cohort of HIV-infected individuals. However, the small subset of vaccinees with a positive vaccine response may have had reduced HBV infection risk, including chronic disease. Improvements in vaccine delivery and immunogenicity are needed to increase HBV vaccine effectiveness in HIV-infected patients.

Hepatitis B vaccine responses in a large U.S. military cohort of HIV-infected individuals: another benefit of HAART in those with preserved CD4 count

The influence of highly active antiretroviral therapy (HAART) upon hepatitis B virus (HBV) vaccine responses in HIV-infected individuals is unclear. After classification of vaccinees as non-responders (HBsAb <10IU/L) or responders (HBsAb >or=10IU/L) in our HIV cohort, multivariate logistic regression was used to assess factors associated with subsequent vaccine response. Of 626 participants vaccinated from 1988 to 2005, 217 (35%) were vaccine responders. Receipt of >or=3 doses of vaccine (OR 1.83, 95% CI 1.24-2.70), higher CD4 count at vaccination (OR 1.09, 95% CI 1.05-1.13 per 50 cells/microl increase), and use of HAART (OR 2.37, 95% CI 1.56-3.62) were all associated with increased likelihood of developing a response. However, only 49% of those on HAART at last vaccination responded, and 62% of those on HAART, with CD4 count >or=350, and HIV RNA <400 copies/mL responded. Compared to those on HAART with CD4 count >or=350, those not on HAART with CD4 count >or=350 had significantly reduced odds of developing a vaccine response (OR 0.47, 95% CI 0.30-0.70). While HAART use concurrent with HBV immunization was associated with increased probability of responding to the vaccine, the response rate was low for those on HAART. These data provide additional evidence of HAART benefits, even in those with higher CD4 counts, but also highlight the need for improving HBV vaccine immunogenicity.