Safety and immunogenicity of an Ad26.ZEBOV booster vaccine in Human Immunodeficiency Virus positive (HIV+) adults previously vaccinated with the Ad26.ZEBOV, MVA-BN-Filo vaccine regimen against Ebola: A single-arm, open-label Phase II clinical trial in Kenya and Uganda

BACKGROUND

People living with HIV constitute an important part of the population in regions at risk of Ebola virus disease outbreaks. The two-dose Ad26.ZEBOV, MVA-BN-Filo Ebola vaccine regimen induces strong immune responses in HIV-positive (HIV+) adults but the durability of this response is unknown. It is also unclear whether this regimen can establish immune memory to enable an anamnestic response upon re-exposure to antigen.

METHODS

This paper describes an open-label, phase 2 trial, conducted in Kenya and Uganda, of Ad26.ZEBOV booster vaccination in HIV+ participants who had previously received the Ad26.ZEBOV, MVA-BN-Filo primary regimen. HIV+ adults with well-controlled infection and on highly active antiretroviral therapy were enrolled, vaccinated with booster, and followed for 28 days. The primary objectives were to assess Ad26.ZEBOV booster safety and antibody responses against the Ebola virus glycoprotein using the Filovirus Animal Non-Clinical Group ELISA.

RESULTS

The Ad26.ZEBOV booster was well-tolerated in HIV+ adults with mostly mild to moderate symptoms. No major safety concerns or serious adverse events were reported. Four and a half years after the primary regimen, 24/26 (92 %) participants were still classified as responders, with a pre-booster antibody geometric mean concentration (GMC) of 726 ELISA units (EU)/mL (95 %CI 447-1179). Seven days after the booster, the GMC increased 54-fold to 38,965 EU/mL (95 %CI 23532-64522). Twenty-one days after the booster, the GMC increased 176-fold to 127,959 EU/mL (95 %CI 93872-174422). The responder rate at both post-booster time points was 100 %.

CONCLUSIONS

The Ad26.ZEBOV booster is safe and highly immunogenic in HIV+ adults with well-controlled infection. The Ad26.ZEBOV, MVA-BN-Filo regimen can generate long-term immune memory persisting for at least 4·5 years, resulting in a robust anamnestic response.

TRIAL REGISTRATION

Pan African Clinical Trial Registry (PACTR202102747294430).

CLINICALTRIALS

gov (NCT05064956).

New Insights on Long-Term Hepatitis B Virus Responses in HIV-Hepatitis B virus Co-infected Patients: Implications for Antiretroviral Management in Hepatitis B virus-Endemic Settings

BACKGROUND

WHO treatment guidelines recommend tenofovir plus lamivudine or emtricitabine as the nucleoside reverse transcriptase inhibitor backbone in first-line regimens for HIV-infected adults. Lamivudine alone is not recommended, because of the risk of hepatitis B virus (HBV) resistance. We studied HBV responses in a large cohort of co-infected patients in a resource-limited setting.

SETTING

Clinical centers in Uganda and Zimbabwe.

METHODS

DART was a randomized trial of monitoring practices in HIV-infected adults starting antiretroviral therapy. Baseline samples were tested retrospectively for HBV serological markers and HBV DNA. Longitudinal HBV DNA testing at 48 weeks and the last available sample before HBV-relevant modification of antiretroviral therapy was performed on patients with detectable HBV DNA at baseline.

RESULTS

Two hundred twenty-four hepatitis B surface antigen-positive patients were followed for up to 4.8 years. Of the drugs with anti-HBV activity, 166 were prescribed lamivudine-tenofovir and 58 lamivudine alone. Ninety-eight percent (96/98) patients with baseline HBV DNA <6 log10 IU/mL achieved viral suppression at 48 weeks (HBV DNA <48 IU/mL), regardless of regimen, compared with 50%(26/52) for HBV DNA >6 log10 IU/mL. Of the 83 patients suppressed at 48 weeks and with follow-up data, only 7(8%) experienced viral rebound (range 200-3460 IU/mL). Of the 20 patients not suppressed at 48 weeks and with follow-up data, HBV DNA levels generally declined with lamivudine-tenofovir, but increased with lamivudine alone. Alanine transaminase flares were not observed in any patient who experienced viral rebound.

CONCLUSIONS

The suppressive effect of lamivudine alone was highly durable (up to 5 years) in HIV-HBV co-infected patients with baseline HBV DNA <6 log10 IU/mL. It may be feasible to develop stratified approaches using lamivudine as the only drug with anti-HBV activity.

Pilot study of antibodies against varicella zoster virus and human immunodeficiency virus in relation to the risk of developing stroke, nested within a rural cohort in Uganda

OBJECTIVE

The risk of stroke rises after episodes of herpes zoster and chickenpox, which are caused by varicella zoster virus (VZV). We conducted a pilot case-control study of stroke, nested within a long-standing cohort in Uganda (the General Population Cohort), to examine antibodies against VZV prior to diagnosis.

METHODS

We used stored sera to examine the evolution of IgG and IgM antibodies against VZV among 31 clinically confirmed cases of stroke and 132 matched controls. For each participant, three samples of sera were identified: one each, taken at or near the time of (pseudo)diagnosis, between 5 and 10 years prior to diagnosis and at 15 years prior to diagnosis.

RESULTS

All participants had detectable antibodies against VZV, but there were no significant differences between cases and controls in the 15 years prior to diagnosis. As a secondary finding, 16% (5/31) of cases and 6% (8/132) of controls had HIV (OR 3.0; 95% CI 0.8-10.1; P = 0.06).

CONCLUSIONS

This is the first prospective study to examine a biological measure of exposure to VZV prior to diagnosis of stroke and although we identified no significant association, in this small pilot, with limited characterisation of cases, we cannot exclude the possibility that the virus is causal for a subset. The impact of HIV on risk of stroke has not been well characterised and warrants further study.