Safety and reactogenicity of a low-dose Diphtheria-Tetanus-Acellular Pertussis vaccine (Boostrix™) in pre-school Indian children

Objective: To evaluate the safety and reactogenicity of a reduced-antigen-content combined Diphtheria-Tetanus-A cellular Pertussis (dTpa) vaccine in Indian pre-school children. Methods: GlaxoSmithKline Biologicals' combination dTpa vaccine was administered as a single booster dose to 347 children aged 4-6 years in seven centers across India. All children were subsequently followed up for two weeks for safety and reactogenicity assessment. Results: A total of 345 subjects completed the study and two subjects were lost to follow-up. One serious adverse event (head injury) unrelated to vaccination was reported. Otherwise, all subjects were in good health throughout the study period. Three subjects (0.9%) reported transient general symptoms (such as irritability and drowsiness), which prevented normal activity. Pain at injection site, swelling and redness was reported in 31.1%, 18.2% and 8.9% subjects respectively. Five subjects (1.4%) reported severe pain preventing normal movement. This resolved within 48 hours. in all cases. There were no other severe local reactions including large injection site reactions. Conclusion: The reduced-antigen-content combined dTpa vaccine is safe and well tolerated in Indian pre-school children.