Philip Bejon

Summary

Affiliation: Kenya Medical Research Institute
Country: Kenya

Publications

  1. pmc Extended follow-up following a phase 2b randomized trial of the candidate malaria vaccines FP9 ME-TRAP and MVA ME-TRAP among children in Kenya
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medicine Research Coast, Kilifi, Kenya
    PLoS ONE 2:e707. 2007
  2. pmc Efficacy of RTS,S malaria vaccines: individual-participant pooled analysis of phase 2 data
    Philip Bejon
    KEMRI Wellcome Trust Research Programme, Kenya Medical Research Institute, Kilifi, Kenya
    Lancet Infect Dis 13:319-27. 2013
  3. pmc Clearing asymptomatic parasitaemia increases the specificity of the definition of mild febrile malaria
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medicine Research Coast, Kenya
    Vaccine 25:8198-202. 2007
  4. pmc The induction and persistence of T cell IFN-gamma responses after vaccination or natural exposure is suppressed by Plasmodium falciparum
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medicine Research Coast Kilifi, Kenya
    J Immunol 179:4193-201. 2007
  5. pmc Fraction of all hospital admissions and deaths attributable to malnutrition among children in rural Kenya
    Philip Bejon
    Kenyan Medical Research Institute Centre for Geographic Medicine Research, Kilifi, Kenya
    Am J Clin Nutr 88:1626-31. 2008
  6. pmc Efficacy of RTS,S/AS01E vaccine against malaria in children 5 to 17 months of age
    Philip Bejon
    Centre for Geographic Medicine Research Coast, Kenya Medical Research Institute, Kilifi, Kenya
    N Engl J Med 359:2521-32. 2008
  7. pmc Analysis of immunity to febrile malaria in children that distinguishes immunity from lack of exposure
    Philip Bejon
    Wellcome Trust KEMRI Collaborative Programme, P O Box 230, Kilife 80108, Kenya
    Infect Immun 77:1917-23. 2009
  8. pmc Effect of the pre-erythrocytic candidate malaria vaccine RTS,S/AS01E on blood stage immunity in young children
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographic Medicine Research, Kilifi, Kenya
    J Infect Dis 204:9-18. 2011
  9. pmc Stable and unstable malaria hotspots in longitudinal cohort studies in Kenya
    Philip Bejon
    Kilifi KEMRI Wellcome Trust Collaborative Research Programme, Centre for Geographic Medicine Research Coast, Kilifi, Kenya
    PLoS Med 7:e1000304. 2010
  10. pmc Defining childhood severe falciparum malaria for intervention studies
    Philip Bejon
    Kenya Medical Research Institute KEMRI Wellcome Trust Collaborative Research Programme, Centre for Geographic Medicine Research Coast, Kilifi, Kenya
    PLoS Med 4:e251. 2007

Detail Information

Publications47

  1. pmc Extended follow-up following a phase 2b randomized trial of the candidate malaria vaccines FP9 ME-TRAP and MVA ME-TRAP among children in Kenya
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medicine Research Coast, Kilifi, Kenya
    PLoS ONE 2:e707. 2007
    ..5, 95% CI 1.0-2.3). Although the study was unblinded, another nine months follow-up was planned to monitor the incidence of malaria and other serious adverse events...
  2. pmc Efficacy of RTS,S malaria vaccines: individual-participant pooled analysis of phase 2 data
    Philip Bejon
    KEMRI Wellcome Trust Research Programme, Kenya Medical Research Institute, Kilifi, Kenya
    Lancet Infect Dis 13:319-27. 2013
    ..To ascertain variations in vaccine efficacy according to covariates such as transmission intensity, choice of adjuvant, age at vaccination, and bednet use, we did an individual-participant pooled analysis of phase 2 clinical data...
  3. pmc Clearing asymptomatic parasitaemia increases the specificity of the definition of mild febrile malaria
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medicine Research Coast, Kenya
    Vaccine 25:8198-202. 2007
    ..In intervention studies with febrile malaria as an endpoint, clearing asymptomatic parasitaemia increases the study's power more effectively than raising the threshold parasitaemia...
  4. pmc The induction and persistence of T cell IFN-gamma responses after vaccination or natural exposure is suppressed by Plasmodium falciparum
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medicine Research Coast Kilifi, Kenya
    J Immunol 179:4193-201. 2007
    ..Malaria may reduce the efficacy vaccinations such as bacillus Calmette-Guérin and investigational T cell-inducing vaccines, and may delay the acquisition of immunity following natural exposure to malaria and other pathogens...
  5. pmc Fraction of all hospital admissions and deaths attributable to malnutrition among children in rural Kenya
    Philip Bejon
    Kenyan Medical Research Institute Centre for Geographic Medicine Research, Kilifi, Kenya
    Am J Clin Nutr 88:1626-31. 2008
    ....
  6. pmc Efficacy of RTS,S/AS01E vaccine against malaria in children 5 to 17 months of age
    Philip Bejon
    Centre for Geographic Medicine Research Coast, Kenya Medical Research Institute, Kilifi, Kenya
    N Engl J Med 359:2521-32. 2008
    ..We evaluated the efficacy of RTS,S given with a more immunogenic adjuvant system (AS01E) in children 5 to 17 months of age, a target population for vaccine licensure...
  7. pmc Analysis of immunity to febrile malaria in children that distinguishes immunity from lack of exposure
    Philip Bejon
    Wellcome Trust KEMRI Collaborative Programme, P O Box 230, Kilife 80108, Kenya
    Infect Immun 77:1917-23. 2009
    ..Observational studies and vaccine trials will have increased power if they differentiate between unexposed and immune children...
  8. pmc Effect of the pre-erythrocytic candidate malaria vaccine RTS,S/AS01E on blood stage immunity in young children
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographic Medicine Research, Kilifi, Kenya
    J Infect Dis 204:9-18. 2011
    ..RTS,S/AS01(E) is the lead candidate malaria vaccine and confers pre-erythrocytic immunity. Vaccination may therefore impact acquired immunity to blood-stage malaria parasites after natural infection...
  9. pmc Stable and unstable malaria hotspots in longitudinal cohort studies in Kenya
    Philip Bejon
    Kilifi KEMRI Wellcome Trust Collaborative Research Programme, Centre for Geographic Medicine Research Coast, Kilifi, Kenya
    PLoS Med 7:e1000304. 2010
    ..This heterogeneity reduces the efficacy of control strategies, but also implies that focusing control strategies on "hotspots" of transmission could be highly effective...
  10. pmc Defining childhood severe falciparum malaria for intervention studies
    Philip Bejon
    Kenya Medical Research Institute KEMRI Wellcome Trust Collaborative Research Programme, Centre for Geographic Medicine Research Coast, Kilifi, Kenya
    PLoS Med 4:e251. 2007
    ....
  11. ncbi request reprint Alternating vector immunizations encoding pre-erythrocytic malaria antigens enhance memory responses in a malaria endemic area
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medical Research Coast, Kilifi, Kenya
    Eur J Immunol 36:2264-72. 2006
    ..Vaccines administered by heterologous prime-boost regimes are being developed for diverse pathogens and cancer. These data suggest these vaccines should also be administered by alternating vector regimens in clinical development...
  12. pmc A statistical interaction between circumsporozoite protein-specific T cell and antibody responses and risk of clinical malaria episodes following vaccination with RTS,S/AS01E
    Francis M Ndungu
    Kenya Medical Research Institute, Centre for Geographical Medical Research Coast, Kilifi, Kenya
    PLoS ONE 7:e52870. 2012
    ..002). Vaccination strategies that combine potent cellular and antibody responses may enhance protection against malaria...
  13. ncbi request reprint Immunogenicity of the candidate malaria vaccines FP9 and modified vaccinia virus Ankara encoding the pre-erythrocytic antigen ME-TRAP in 1-6 year old children in a malaria endemic area
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medical Research, Coast, Kenya
    Vaccine 24:4709-15. 2006
    ..The potential for enhanced immunogenicity with half doses of priming vectors warrants further investigation, and larger studies to determine protection against malaria in children are required...
  14. doi request reprint Four-year efficacy of RTS,S/AS01E and its interaction with malaria exposure
    Ally Olotu
    Centre for Geographic Medicine Research, Kenya Medical Research Institute KEMRI Wellcome Trust Research Programme, Kilifi, Kenya
    N Engl J Med 368:1111-20. 2013
    ..The candidate malaria vaccine RTS,S/AS01E has entered phase 3 trials, but data on long-term outcomes are limited...
  15. pmc Estimating individual exposure to malaria using local prevalence of malaria infection in the field
    Ally Olotu
    Kenya Medical Research Institute, Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
    PLoS ONE 7:e32929. 2012
    ..Analysis may be facilitated by taking into account the variability in individual exposure levels, but it is unclear how exposure can be estimated at an individual level...
  16. pmc Defining clinical malaria: the specificity and incidence of endpoints from active and passive surveillance of children in rural Kenya
    Ally Olotu
    Kenya Medical Research Institute Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
    PLoS ONE 5:e15569. 2010
    ..Subjective and objective fevers are both used to define the endpoint, but have not been carefully compared, and the relative incidence of clinical malaria by active and passive case detection is unknown...
  17. pmc Chronic exposure to Plasmodium falciparum is associated with phenotypic evidence of B and T cell exhaustion
    Joseph Illingworth
    Kenya Medical Research Institute, Centre for Geographical Medicine Research Coast, Kilifi, Kenya
    J Immunol 190:1038-47. 2013
    ..Taken together, these results suggest that P. falciparum infection per se drives the expansion of atypical MBCs and phenotypically exhausted CD4 T cells, which has been reported in other endemic areas...
  18. pmc Circumsporozoite-specific T cell responses in children vaccinated with RTS,S/AS01E and protection against P falciparum clinical malaria
    Ally Olotu
    Kenya Medical Research Institute Wellcome Trust Programme, Centre for Geographic Medicine Research, Coast, Kilifi, Kenya
    PLoS ONE 6:e25786. 2011
    ..falciparum. We studied CS-specific T cell responses in order to identify correlates of protection...
  19. pmc HIV infection, malnutrition, and invasive bacterial infection among children with severe malaria
    James A Berkley
    Centre for Geographic Medicine Research, Kilifi, Kenya
    Clin Infect Dis 49:336-43. 2009
    ..However, it is unclear whether their cooccurrence with falciparum parasitization and severe disease happens by chance or by association among children in areas where malaria is endemic...
  20. ncbi request reprint Safety profile of the viral vectors of attenuated fowlpox strain FP9 and modified vaccinia virus Ankara recombinant for either of 2 preerythrocytic malaria antigens, ME-TRAP or the circumsporozoite protein, in children and adults in Kenya
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medical Research Coast, Kilifi, Kenya
    Clin Infect Dis 42:1102-10. 2006
    ....
  21. pmc Helminth infection and eosinophilia and the risk of Plasmodium falciparum malaria in 1- to 6-year-old children in a malaria endemic area
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medicine Research Coast, Kilifi, Kenya
    PLoS Negl Trop Dis 2:e164. 2008
    ..Animal models suggest that helminth infections may increase susceptibility to malaria, but epidemiological data has been limited and contradictory...
  22. pmc Efficacy of RTS,S/AS01E malaria vaccine and exploratory analysis on anti-circumsporozoite antibody titres and protection in children aged 5-17 months in Kenya and Tanzania: a randomised controlled trial
    Ally Olotu
    Kenya Medical Research Institute Wellcome Trust Programme, Centre for Geographic Medicine Research, Kenya Medical Research Institute, Kilifi, Kenya
    Lancet Infect Dis 11:102-9. 2011
    ..We recently showed efficacy against clinical falciparum malaria in 5-17 month old children, during an average of 8 months follow-up. We aimed to assess the efficacy of RTS,S/AS01E during 15 months of follow-up...
  23. pmc Lack of avidity maturation of merozoite antigen-specific antibodies with increasing exposure to Plasmodium falciparum amongst children and adults exposed to endemic malaria in Kenya
    Frances Ibison
    Kenya Medical Research Institute, Centre for Geographical Medicine Research Coast, Kilifi, Kenya
    PLoS ONE 7:e52939. 2012
    ....
  24. pmc Early gamma interferon and interleukin-2 responses to vaccination predict the late resting memory in malaria-naïve and malaria-exposed individuals
    Philip Bejon
    Kenya Medical Research Institute, Centre for Geographical Medical Research Coast, P O Box 230, Kilifi, Kenya
    Infect Immun 74:6331-8. 2006
    ..This demonstrated that double-cytokine-producing cells were highly predictive of memory. This assay may be useful in predicting vaccinations most likely to generate stable, long-term memory responses...
  25. pmc Wind direction and proximity to larval sites determines malaria risk in Kilifi District in Kenya
    Janet T Midega
    KEMRI Wellcome Trust Collaborative Research Programme, Centre for Geographic Medicine Research Coast, PO Box 230, Kilifi 80108, Kenya
    Nat Commun 3:674. 2012
    ..We conclude that following oviposition, female Anophelines fly upwind in search for human hosts and, thus, malaria transmission may be disrupted by targeting vector larval sites in close proximity, and downwind to malaria hotspots...
  26. pmc Quantitative PCR evaluation of cellular immune responses in Kenyan children vaccinated with a candidate malaria vaccine
    Jedidah Mwacharo
    Centre for Geographical Medical Research, Kenya Medical Research Institute, Kilifi, Kenya
    PLoS ONE 4:e8434. 2009
    ....
  27. pmc Interactions between age and ITN use determine the risk of febrile malaria in children
    Philip Bejon
    Kenyan Medical Research Institute KEMRI, Centre for Geographic Medicine Research Coast, Kilifi, Kenya
    PLoS ONE 4:e8321. 2009
    ..However, the more common practice in Sub-Saharan Africa is to target ITN distribution on young children. There are few data on the long term outcomes of this practice...
  28. ncbi request reprint B cell memory to 3 Plasmodium falciparum blood-stage antigens in a malaria-endemic area
    Jeffrey R Dorfman
    Kenya Medical Research Institute, Wellcome Trust Research Laboratories, Kilifi, Kenya
    J Infect Dis 191:1623-30. 2005
    ....
  29. pmc Serological evidence of discrete spatial clusters of Plasmodium falciparum parasites
    Philip Bejon
    Centre for Geographic Medicine Research, Kenya Medical Research Institute Wellcome Trust Programme, Coast, Kilifi, Kenya
    PLoS ONE 6:e21711. 2011
    ..Since the Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) is highly polymorphic, the host's serological responses may be used to infer exposure to parasite sub-populations...
  30. pmc Feedback of research findings for vaccine trials: experiences from two malaria vaccine trials involving healthy children on the Kenyan Coast
    Caroline Gikonyo
    KEMRI Wellcome Trust Research Programme, 230, Kilifi, Coast 80108, Kenya
    Dev World Bioeth 13:48-56. 2013
    ....
  31. pmc Taking social relationships seriously: lessons learned from the informed consent practices of a vaccine trial on the Kenyan Coast
    Caroline Gikonyo
    KEMRI Wellcome Trust Research Programme, P O Box 230, Kilifi, Kenya
    Soc Sci Med 67:708-20. 2008
    ....
  32. ncbi request reprint Invasive Gram-negative bacilli are frequently resistant to standard antibiotics for children admitted to hospital in Kilifi, Kenya
    Philip Bejon
    Wellcome Trust Kenya Medical Research Institute KEMRI, Centre for Geographic Medicine Research Coast, Kilifi, Kenya
    J Antimicrob Chemother 56:232-5. 2005
    ....
  33. pmc What you see is not what you get: implications of the brevity of antibody responses to malaria antigens and transmission heterogeneity in longitudinal studies of malaria immunity
    Samson M Kinyanjui
    Kenyan Medical Research Institute KEMRI, Centre for Geographic Medicine Research Coast, PO Box 230, Kilifi 80108, Kenya
    Malar J 8:242. 2009
    ..This approach has identified a number of important responses against malaria, but their protective efficacies vary considerably between studies...
  34. pmc Memory B cells are a more reliable archive for historical antimalarial responses than plasma antibodies in no-longer exposed children
    Francis Maina Ndungu
    Kenya Medical Research Institute, Centre for Geographical Medical Research Coast, Box 230, 80108 Kilifi, Kenya
    Proc Natl Acad Sci U S A 109:8247-52. 2012
    ..We conclude that serological analysis by itself would greatly underestimate the true memory of Pf-specific Ab responses in previously exposed children living in areas where Pf transmission has been reduced or eliminated...
  35. pmc Acute seizures attributable to falciparum malaria in an endemic area on the Kenyan coast
    Symon M Kariuki
    Centre for Geographic Medicine Research Coast, Kenya Medical Research Institute, Kilifi, Kenya, PO Box 230 Kilifi 80108, Kenya
    Brain 134:1519-28. 2011
    ..The reduction in malaria has decreased the burden of seizures that are attributable to malaria and this could lead to reduced neurological disabilities and epilepsy in the area...
  36. pmc Incorporating a quiz into informed consent processes: qualitative study of participants' reactions
    Sassy Molyneux
    Senior Research Fellow, Kenya Medical Research Institute Centre for Geographic Medicine Research Coast KEMRI CGMRC Wellcome Trust Research Programme, Kilifi, Kenya, P O Box 230
    Malar J 6:145. 2007
    ..The quiz was administered to 189 mothers after consenting for their children to participate in a malaria vaccine trial on the Kenyan Coast...
  37. pmc Enhanced T cell-mediated protection against malaria in human challenges by using the recombinant poxviruses FP9 and modified vaccinia virus Ankara
    Daniel P Webster
    Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Churchill Hospital, Old Road, Oxford OX3 7LJ, UK
    Proc Natl Acad Sci U S A 102:4836-41. 2005
    ....
  38. ncbi request reprint Quantitative real-time polymerase chain reaction for malaria diagnosis and its use in malaria vaccine clinical trials
    Laura Andrews
    Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
    Am J Trop Med Hyg 73:191-8. 2005
    ..This PCR method has so far been used to follow 137 vaccinee and control volunteers in Phase IIa trials in Oxford and on 220 volunteer samples during a Phase IIb field trial in The Gambia...
  39. ncbi request reprint Durable human memory T cells quantifiable by cultured enzyme-linked immunospot assays are induced by heterologous prime boost immunization and correlate with protection against malaria
    Sheila M Keating
    Centre for Clinical Vaccinology and Tropical Medicine, Nuffield Department of Medicine, Churchill Hospital, Oxford, United Kingdom
    J Immunol 175:5675-80. 2005
    ..This cultured assay identifies long-lasting protective T cell responses and therefore offers an attractive option for assessments of vaccine immunogenicity...
  40. ncbi request reprint A clinical trial of prime-boost immunisation with the candidate malaria vaccines RTS,S/AS02A and MVA-CS
    Susanna J Dunachie
    Centre for Clinical Vaccinology and Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, UK
    Vaccine 24:2850-9. 2006
    ..Protection against 3D7 Plasmodium falciparum sporozoite challenge 4 weeks after the final vaccination was equal for both regimens at 33% (95% C.I. 4.3-77.7%), with one subject remaining fully protected on rechallenge at 5 months...
  41. ncbi request reprint Calculation of liver-to-blood inocula, parasite growth rates, and preerythrocytic vaccine efficacy, from serial quantitative polymerase chain reaction studies of volunteers challenged with malaria sporozoites
    Philip Bejon
    Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, United Kingdom
    J Infect Dis 191:619-26. 2005
    ..Forty-eight-hour growth rates in blood from control subjects were not different from those in blood from any vaccination group (mean, 14.4-fold [95% confidence interval, 11-19-fold])...
  42. ncbi request reprint Upregulation of TGF-beta, FOXP3, and CD4+CD25+ regulatory T cells correlates with more rapid parasite growth in human malaria infection
    Michael Walther
    Center for Clinical Vaccinology and Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Churchill Hospital, Oxford OX3 7LJ, United Kingdom
    Immunity 23:287-96. 2005
    ..P. falciparum-mediated induction of regulatory T cells may represent a parasite-specific virulence factor...
  43. ncbi request reprint Innate immune responses to human malaria: heterogeneous cytokine responses to blood-stage Plasmodium falciparum correlate with parasitological and clinical outcomes
    Michael Walther
    Center for Clinical Vaccinology and Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Churchill Hospital, Oxford, United Kingdom
    J Immunol 177:5736-45. 2006
    ..Furthermore, the in vitro observations on cytokine kinetics presented here, suggest that intact schizont-stage infected RBC can trigger innate responses before rupture of the infected RBC...
  44. doi request reprint Longitudinal analyses of immune responses to Plasmodium falciparum derived peptides corresponding to novel blood stage antigens in coastal Kenya
    George W Agak
    Department of Biochemistry, University of Lausanne, Chemin des Boveresses 155, 1066 Epalinges, Switzerland
    Vaccine 26:1963-71. 2008
    ..The current study substantiates further the potential of protein PFB0145c and also identifies protein PF11_0424 as another likely target of protective antibodies against P. falciparum malaria...
  45. pmc Correlation of memory T cell responses against TRAP with protection from clinical malaria, and CD4 CD25 high T cells with susceptibility in Kenyans
    Stephen M Todryk
    Centre for Clinical Vaccinology and Tropical Medicine, Oxford University, Churchill Hospital, Oxford, United Kingdom
    PLoS ONE 3:e2027. 2008
    ....
  46. pmc Thick blood film examination for Plasmodium falciparum malaria has reduced sensitivity and underestimates parasite density
    Philip Bejon
    Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, OX3 7LJ, UK
    Malar J 5:104. 2006
    ..Thick blood films are routinely used to diagnose Plasmodium falciparum malaria. Here, they were used to diagnose volunteers exposed to experimental malaria challenge...
  47. ncbi request reprint Blood-stage challenge for malaria vaccine efficacy trials: a pilot study with discussion of safety and potential value
    Frances Sanderson
    Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, United Kingdom
    Am J Trop Med Hyg 78:878-83. 2008
    ..This finding may provide greater power to detect partial efficacy of many blood-stage candidate vaccines. We discuss the potential utility of blood-stage challenge studies in accelerating malaria vaccine development...