Safety and tolerability of conserved region vaccines vectored by plasmid DNA, simian adenovirus and modified vaccinia virus ankara administered to human immunodeficiency virus type 1-uninfected adults in a randomized, single-blind phase I trial

PLoS One. 2014 Jul 9;9(7):e101591. doi: 10.1371/journal.pone.0101591. eCollection 2014.


Trial design: HIV-1 vaccine development has advanced slowly due to viral antigenic diversity, poor immunogenicity and recently, safety concerns associated with human adenovirus serotype-5 vectors. To tackle HIV-1 variation, we designed a unique T-cell immunogen HIVconsv from functionally conserved regions of the HIV-1 proteome, which were presented to the immune system using a heterologous prime-boost combination of plasmid DNA, a non-replicating simian (chimpanzee) adenovirus ChAdV-63 and a non-replicating poxvirus, modified vaccinia virus Ankara. A block-randomized, single-blind, placebo-controlled phase I trial HIV-CORE 002 administered for the first time candidate HIV-1- vaccines or placebo to 32 healthy HIV-1/2-uninfected adults in Oxford, UK and elicited high frequencies of HIV-1-specific T cells capable of inhibiting HIV-1 replication in vitro. Here, detail safety and tolerability of these vaccines are reported.

Methods: Local and systemic reactogenicity data were collected using structured interviews and study-specific diary cards. Data on all other adverse events were collected using open questions. Serum neutralizing antibody titres to ChAdV-63 were determined before and after vaccination.

Results: Two volunteers withdrew for vaccine-unrelated reasons. No vaccine-related serious adverse events or reactions occurred during 190 person-months of follow-up. Local and systemic events after vaccination occurred in 27/32 individuals and most were mild (severity grade 1) and predominantly transient (<48 hours). Myalgia and flu-like symptoms were more strongly associated with MVA than ChAdV63 or DNA vectors and more common in vaccine recipients than in placebo. There were no intercurrent HIV-1 infections during follow-up. 2/24 volunteers had low ChAdV-63-neutralizing titres at baseline and 7 increased their titres to over 200 with a median (range) of 633 (231-1533) post-vaccination, which is of no safety concern.

Conclusions: These data demonstrate safety and good tolerability of the pSG2.HIVconsv DNA, ChAdV63.HIVconsv and MVA.HIVconsv vaccines and together with their high immunogenicity support their further development towards efficacy studies.

Trial registration: NCT01151319.

Publication types

  • Clinical Trial, Phase I
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • AIDS Vaccines / immunology*
  • Adenoviruses, Simian / genetics
  • Adenoviruses, Simian / immunology*
  • Adolescent
  • Adult
  • Antibodies, Neutralizing / blood
  • Conserved Sequence
  • Female
  • Genetic Vectors
  • HEK293 Cells
  • HIV Antibodies / blood
  • HIV Infections / prevention & control*
  • HIV-1 / genetics
  • HIV-1 / immunology*
  • Human Immunodeficiency Virus Proteins / genetics
  • Human Immunodeficiency Virus Proteins / immunology
  • Humans
  • Male
  • Middle Aged
  • Plasmids / genetics
  • Single-Blind Method
  • Vaccines, Synthetic / genetics
  • Vaccines, Synthetic / immunology
  • Vaccinia virus / genetics
  • Vaccinia virus / immunology*
  • Virus Replication
  • Young Adult


  • AIDS Vaccines
  • Antibodies, Neutralizing
  • HIV Antibodies
  • Human Immunodeficiency Virus Proteins
  • Vaccines, Synthetic

Associated data