A Randomized, Controlled, Observer-Blinded Phase 1 Study of the Safety and Immunogenicity of a Respiratory Syncytial Virus Vaccine With or Without Alum Adjuvant

J Infect Dis. 2017 Jan 1;215(1):24-33. doi: 10.1093/infdis/jiw453. Epub 2016 Sep 29.


Background: Respiratory syncytial virus (RSV) is a leading cause of childhood bronchiolitis and pneumonia, particularly in early infancy. Immunization of pregnant women could boost preexisting immune responses, providing passive protection to newborns through placental transfer of anti-RSV antibody.

Methods: In this first-in-humans clinical trial of a purified recombinant RSV protein F vaccine engineered to preferentially maintain prefusion conformation (RSV-PreF), 128 healthy men 18-44 years old were randomized to one dose of a RSV-PreF vaccine containing 10, 30, or 60 µg of RSV-PreF antigen, with or without alum adjuvant, or control, and followed for one year for safety and immunogenicity outcomes.

Results: Injection site pain was the most common adverse event, reported by up to 81.3% of participants. The highest RSV neutralizing antibody responses were in the 30 µg RSV-PreF/alum, 60 µg RSV-PreF/alum, and 60 µg RSV-PreF/nonadjuvant groups. Responses were evident on day 7, and 30 days after vaccination these participants had RSV-A neutralizing antibody titers of ≥1:512, and >70% had titers of 1:1024, with titers increasing by 3.2-4.9 fold. Responses remained high on day 60 but waned on days 180 and 360.

Conclusions: The RSV-PreF vaccine elicited rapid RSV neutralizing antibody responses in healthy young men, with an acceptable adverse event profile.

Keywords: maternal immunization; respiratory syncytial virus; vaccine; vaccine safety and immunogenicity.

Publication types

  • Clinical Trial, Phase I
  • Randomized Controlled Trial

MeSH terms

  • Adjuvants, Immunologic*
  • Adolescent
  • Adult
  • Alum Compounds
  • Antibodies, Neutralizing / blood
  • Antibodies, Viral / blood
  • Antigens, Viral / immunology
  • Female
  • Humans
  • Male
  • Pregnancy
  • Respiratory Syncytial Virus Infections / immunology*
  • Respiratory Syncytial Virus Infections / prevention & control*
  • Respiratory Syncytial Virus Infections / virology
  • Respiratory Syncytial Virus Vaccines / administration & dosage
  • Respiratory Syncytial Virus Vaccines / adverse effects*
  • Respiratory Syncytial Virus Vaccines / immunology*
  • Respiratory Syncytial Virus, Human / chemistry
  • Respiratory Syncytial Virus, Human / immunology*
  • Vaccines, Synthetic / administration & dosage
  • Vaccines, Synthetic / adverse effects
  • Vaccines, Synthetic / immunology
  • Viral Fusion Proteins / administration & dosage
  • Viral Fusion Proteins / genetics
  • Viral Fusion Proteins / immunology
  • Viral Fusion Proteins / isolation & purification
  • Young Adult


  • Adjuvants, Immunologic
  • Alum Compounds
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Antigens, Viral
  • Respiratory Syncytial Virus Vaccines
  • Vaccines, Synthetic
  • Viral Fusion Proteins
  • aluminum sulfate