Trial reportCurrent opinion in HIV and AIDS2010
Overview of STEP and Phambili trial results: two phase IIb test-of-concept studies investigating the efficacy of MRK adenovirus type 5 gag/pol/nef subtype B HIV vaccine.
Trial report in Current opinion in HIV and AIDS, 2010. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 95 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
95 citing papers in PubMed, 1 synthesis or guideline pooled it, 169 citations in OpenAlex.
- Descriptions of risks and benefits of HIV vaccine trials in low-and middle-income countries (LMICs): an integrative review.BMC medical ethics · 2025Pooled it
- Effect of HIV Envelope Vaccination on the Subsequent Antibody Response to HIV Infection.mSphere · 2020Trial
- Live attenuated varicella-zoster virus vaccine does not induce HIV target cell activation.The Journal of clinical investigation · 2019Trial
- Perception of potential harm and benefits of HIV vaccine trial participation: A qualitative study from urban Tanzania.PloS one · 2019Trial
- Safety and Immunogenicity of a rAd35-EnvA Prototype HIV-1 Vaccine in Combination with rAd5-EnvA in Healthy Adults (VRC 012).PloS one · 2016Trial
- Recombinant adenovirus type 5 HIV gag/pol/nef vaccine in South Africa: unblinded, long-term follow-up of the phase 2b HVTN 503/Phambili study.The Lancet. Infectious diseases · 2014Trial
- Trial
- Sexual risk behaviors, circumcision status, and preexisting immunity to adenovirus type 5 among men who have sex with men participating in a randomized HIV-1 vaccine efficacy trial: step study.Journal of acquired immune deficiency syndromes (1999) · 2012Trial
- Safety and efficacy of the HVTN 503/Phambili study of a clade-B-based HIV-1 vaccine in South Africa: a double-blind, randomised, placebo-controlled test-of-concept phase 2b study.The Lancet. Infectious diseases · 2011Trial
- A Population-Based HIV Vaccine Efficacy Trial Design: Statistical Framework and Design Considerations.Vaccines · 2026Review
- Can Humanized Immune System Mouse and Rat Models Accelerate the Development of Cytomegalovirus-Based Vaccines Against Infectious Diseases and Cancers?International journal of molecular sciences · 2025Review
- Review
- Human Immunodeficiency Virus Vaccine: Promise and Challenges.Infectious disease clinics of North America · 2024Review
- Article
- Review
- Review
- Review
- High-Throughput Screening for the Prevalence of Neutralizing Antibodies against Human Adenovirus Serotype 5.Vaccines · 2024Article
- Enhancing broadly neutralising antibody suppression of HIV by immune modulation and vaccination.Frontiers in immunology · 2024Review
- The Question of HIV Vaccine: Why Is a Solution Not Yet Available?Journal of immunology research · 2024Review
35 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 3 institutions in 2 countries.
Funding
Abstract
purpose of reviewTwo phase IIb test-of-concept studies evaluated the replication-defective adenovirus type 5 (Ad5) vaccine MRK gag/pol/nef HIV vaccine to prevent infection or decrease early plasma viral load in disparate populations. The STEP study enrolled men and women in the Americas, Caribbean and Australia; the Phambili trial enrolled men and women in South Africa, where the modes of sexual transmission and HIV-1 risk, subtypes of HIV-1, and background Ad5 seroprevalence differed. RECENT
findingsVaccination in both studies were stopped, after the first interim efficacy analysis of the STEP study crossed predetermined nonefficacy boundaries. Neither trial demonstrated a decrease in HIV acquisition nor decreased early plasma viral load in vaccinees compared with placebo recipients. Post-hoc analyses of men enrolled in the STEP study showed a larger number of HIV infections in the subgroup of vaccinated men who were Ad5-seropositive and uncircumcised compared with a comparable placebo group. This was not demonstrated in the Phambili study, in which most men were heterosexual, whereas most in STEP were homosexual/bisexual. Further analysis of the STEP study has yet to explain the effect of Ad5 seroprevalence on increased HIV-1 susceptibility in men receiving the vaccine. However, promising vaccine effects on early viral control were seen, and the possibility of effects on early viral load set-point in women in Phambili was seen. SUMMARY: These trials have provided a number of lessons about the importance of clinical trials in the HIV vaccine discovery process, and insight into the type and level of immune response that will be required for control of viral replication.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.