Vaccine Info

IVX-121 Respiratory Syncytial Virus (RSV) Vaccine


IVX-121 an RSV vaccine candidate incorporates a stabilized prefusion F antigen licensed from NIAID/NIH (DS-CAV1).

IVX-121 will utilize the application of Vaccine-Like Particles (VLP) technology to the DS-CAV1.

VLPs enable high-density, multivalent display of antigens in a manner that closely resembles viruses, with an important difference. VLPs contain no genetic material, so they are non-infectious and can provide a safer alternative to live-attenuated or inactivated vaccines. 


IVX-121 is a vaccine candidate for respiratory syncytial virus (RSV) for older adults 


IVX-121 is administered as an intramuscular injection


October 3, 2019: Icosavax announces $51 Million Dollars Raised For RSV Vaccine Development

Clinical Trial

Clinical Trial NCT03049488: Dose, Safety, Tolerability and Immunogenicity of a Stabilized Prefusion RSV F Subunit Protein Vaccine, VRC-RSVRGP084-00-VP (DS-Cav1), Alone or With Alum Adjuvant, in Healthy Adults


  • RSV is a virus that infects the lungs and breathing passages. Healthy adults who are infected generally have mild cold symptoms for a week or two. But it can also be serious, especially for infants and older adults. It can be spread by direct or indirect contact with respiratory secretions. Researchers want to study a new vaccine to prevent RSV.


  • To see if a vaccine for RSV is safe and if it causes side effects.


  • Participants will be screened in a different protocol.
  • Participants will have 13 visits over 1 year.
  • Some participants will receive just vaccine. Some will receive vaccine mixed with alum, which could make the body respond to the vaccine better.
  • All will receive their dose by injection in the upper arm. They will receive two doses, one at the beginning of the study and another 12 weeks later.
  • Participants will be watched for 1 hour after injection. They will be called 1 day after.
  • They will keep track of their temperature and side effects for 7 days after.
  • Participants will receive a ruler to measure any changes on their skin at the injection site.
  • At all visits, participants will be checked for health changes or problems. They may have blood drawn.
  • At some visits, participants will have samples taken from their nose and mouth.