Respiratory syncytial virus (RSV) is the most important cause of severe acute lower respiratory illness in infants and children and the most common cause of severe

pneumonia requiring hospital admission in children worldwide. According to global estimates, RSV caused approximately 33 million cases of lower respiratory illness and approximately 118,000 deaths in children < 5 years of age in 2015.Infants and young children are at increased risk for RSV infections because of their maturing immune system and lack of prior exposure to RSV.

A genetically stable live-attenuated RSV ΔNS2/Δ1313/I1314L vaccine has been shown to be safe and immunogenic in RSV-seronegative children in Phase I studies with further research ongoing in RSV-seropositive children. Sanofi is conducting clinical studies with a similar RSV ΔNS2/Δ1313/I1314L vaccine, referred to as RSVt vaccine, as part of the Phase III development of the RSVt vaccine (the VAD0004 study).

 

The VAD0004 study, is a Phase III, randomized, observer-blind, placebo-controlled, multi-center, multinational study to evaluate the efficacy, immunogenicity, and safety of a Respiratory Syncytial Virus vaccine in infants and toddlers. The study is designed to evaluate the efficacy, immunogenicity, and safety of RSVt vaccine administered by intranasal route and compared to placebo.

Overall, a global sample size of approximately 6300 participants 6 months to < 22 months of age will be enrolled in the study. Kenya site will enroll approximately 1500 participants. Eligible participants will be randomized in a 1:1 ratio to receive 2 intranasal administrations of either the RSVt vaccine or placebo.Study duration will be 24months for each participant. The safety evaluation will start after the first vaccination and up to the end of the study. The trial will target recruitment of people from different races and ethnic groups that at a minimum will be representative of the countries in which the trial will be conducted.