Respiratory Syncytial Virus (RSV) is a contagious virus (germ) that circulates particularly during the winter months and throughout the year in some parts of the world. It is transmitted through droplets containing the virus when someone infected sneezes or coughs. In most infants, the RSV infection will be a mild illness similar to a cold, with symptoms such as fever, runny nose, sore throat, ear infection, cough, and croup (barky cough with hoarseness). In some cases, RSV can cause serious lung illnesses such as pneumonia and bronchiolitis (an infection of small airways in the lung called bronchioles), which may lead to hospitalization. At this time, there is no approved vaccine to prevent RSV illness.

Sanofi Pasteur is developing a vaccine called the RSVt vaccine. The study is called VAD00004 and is a Phase III trial, with two study arms, multiple research sites in multiple countries. in Kenya there are  a total of 7 sites. It will be conducted in infants and toddlers 6 months to less than 22 months of age to evaluate if the vaccine works, how safe it is and how the human body responds to protect itself following vaccination of 2 intranasal spray of RSVt vaccine. The trial is designed to demonstrate how the vaccine works in preventing the occurrence of respiratory syncytial Virus.

The investigational RSVt vaccine in this study contains a live, weakened form of the virus (that is, attenuated) and is given as a nasal spray. It is made to help a person’s body respond in a way that will protect them from getting sick from the virus. The vaccine has been tested in humans before, and other live attenuated RSV vaccines very similar to this one has also been tested in both adults and children.

A total of  6300 children are planned to be enrolled worldwide. Eligible participants will be randomized in a 1:1 ratio to receive 2 intranasal administrations 56 days apart of either the RSVt vaccine or placebo at day 1 and day 57 of the study. Additional illness visits may occur during the study for those who develops RSV like symptoms. Each participant will be followed for 24 months in the study. Kenya will enroll approximately 15000  up to 1000 children.

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.