RSV - respiratory syncytial virus is one of the common causes of respiratory diseases in infants and young children with the ability to spread very strongly. There is currently no vaccine to protect children from this virus. RSV infection is the leading cause of bronchiolitis and pneumonia in children under two years old and it is very dangerous for children. This disease can occur year-round but is usually in the rainy season in the southern provinces or the cold season in the northern provinces.