Trial reportPloS one2011
Impact on malaria parasite multiplication rates in infected volunteers of the protein-in-adjuvant vaccine AMA1-C1/Alhydrogel+CPG 7909.
Trial report in PloS one, 2011. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT00984763 (A Phase I/IIa Study of the Safety, Immunogenicity and Parasite Growth Inhibitory Activity of AMA1-C1/Alhydrogel® + CPG 7909, an Asexual Blood Stage Vaccine for Plasmodium Falciparum Malaria), which is not on this map. Cited by 54 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.
A Phase I/IIa Study of the Safety, Immunogenicity and Parasite Growth Inhibitory Activity of AMA1-C1/Alhydrogel® + CPG 7909, an Asexual Blood Stage Vaccine for Plasmodium Falciparum Malaria
Who cites it
54 citing papers in PubMed, 1 synthesis or guideline pooled it, 95 citations in OpenAlex.
- Neutropenia as an Adverse Event following Vaccination: Results from Randomized Clinical Trials in Healthy Adults and Systematic Review.PloS one · 2016Pooled it
- Safety and immunogenicity of BK-SE36/CpG malaria vaccine in healthy Burkinabe adults and children: a phase 1b randomised, controlled, double-blinded, age de-escalation trial.Frontiers in immunology · 2023Trial
- Repeat controlled human malaria infection of healthy UK adults with blood-stageFrontiers in immunology · 2022Trial
- A controlled human malaria infection model enabling evaluation of transmission-blocking interventions.The Journal of clinical investigation · 2018Trial
- Demonstration of the Blood-Stage Plasmodium falciparum Controlled Human Malaria Infection Model to Assess Efficacy of the P. falciparum Apical Membrane Antigen 1 Vaccine, FMP2.1/AS01.The Journal of infectious diseases · 2016Trial
- Trial
- Assessment of immune interference, antagonism, and diversion following human immunization with biallelic blood-stage malaria viral-vectored vaccines and controlled malaria infection.Journal of immunology (Baltimore, Md. : 1950) · 2013Trial
- Trial
- Controlled human malaria infection: overview and potential application in the evaluation of transmission-blocking interventions in malaria-endemic areas.Malaria journal · 2025Review
- Controlled human malaria infection studies: insights into recent advances and key immunological and ethical implementation lessons.Frontiers in immunology · 2025Review
- Controlled Human Malaria Infection Studies in Africa-Past, Present, and Future.Current topics in microbiology and immunology · 2024Review
- Review
- Current approaches to malaria vaccines.Current opinion in microbiology · 2022Review
- The challenges ofFrontiers in immunology · 2022Article
- Evaluation of the AV7909 Anthrax Vaccine Toxicity in Sprague Dawley Rats Following Three Intramuscular Administrations.International journal of toxicology · 2021Article
- Review
- Mechanistic within-host models of the asexual Plasmodium falciparum infection: a review and analytical assessment.Malaria journal · 2021Article
- Reduced blood-stage malaria growth and immune correlates in humans following RH5 vaccination.Med (New York, N.Y.) · 2021Article
- Bliss' and Loewe's additive and synergistic effects in Plasmodium falciparum growth inhibition by AMA1-RON2L, RH5, RIPR and CyRPA antibody combinations.Scientific reports · 2020Article
- Growth Rate of Plasmodium falciparum: Analysis of Parasite Growth Data From Malaria Volunteer Infection Studies.The Journal of infectious diseases · 2020Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
28 authors at 3 institutions in 2 countries.
Funding
Abstract
backgroundInhibition of parasite growth is a major objective of blood-stage malaria vaccines. The in vitro assay of parasite growth inhibitory activity (GIA) is widely used as a surrogate marker for malaria vaccine efficacy in the down-selection of candidate blood-stage vaccines. Here we report the first study to examine the relationship between in vivo Plasmodium falciparum growth rates and in vitro GIA in humans experimentally infected with blood-stage malaria.
methodsIn this phase I/IIa open-label clinical trial five healthy malaria-naive volunteers were immunised with AMA1/C1-Alhydrogel+CPG 7909, and together with three unvaccinated controls were challenged by intravenous inoculation of P. falciparum infected erythrocytes.
resultsA significant correlation was observed between parasite multiplication rate in 48 hours (PMR) and both vaccine-induced growth-inhibitory activity (Pearson r = -0.93 [95% CI: -1.0, -0.27] P = 0.02) and AMA1 antibody titres in the vaccine group (Pearson r = -0.93 [95% CI: -0.99, -0.25] P = 0.02). However immunisation failed to reduce overall mean PMR in the vaccine group in comparison to the controls (vaccinee 16 fold [95% CI: 12, 22], control 17 fold [CI: 0, 65] P = 0.70). Therefore no impact on pre-patent period was observed (vaccine group median 8.5 days [range 7.5-9], control group median 9 days [range 7-9]).
conclusionsDespite the first observation in human experimental malaria infection of a significant association between vaccine-induced in vitro growth inhibitory activity and in vivo parasite multiplication rate, this did not translate into any observable clinically relevant vaccine effect in this small group of volunteers.
trial registrationClinicalTrials.gov [NCT00984763].
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Identifiers
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.