Protective Effect of Antibody to Parainfluenza Type 1 Virus

PARAINFLUENZA Type 1 virus is an important cause of acute respiratory disease in infants and children.1 , 2 During primary infection the lower respiratory tract is often involved, and illness may be quite severe. Initial infection usually occurs during childhood, and most older children and adults have serum neutralizing antibody to this virus.2 Reinfection with Type 1 virus has been observed in adults under both experimental and natural conditions despite the presence of serum neutralizing antibody.3 4 5 Illness associated with reinfection is generally mild and limited to the upper respiratory tract.Adults and older children undergoing reinfection probably constitute an important source of . . .