Comparison of the reactogenicity of three different immunization schedules including diphtheria, tetanus, pertussis, Haemophilus influenza b and polio vaccine in Turkey

Background: In Turkey, several changes have been made in the vaccination schedule. Vaccines against diphtheria, tetanus, pertussis and poliomyelitis were applied as DTwP and OPV until the end of 2006. Hib vaccine was added to the schedule and was administered as a separate injection in 2007 as DPT + OPV + Hib. DTaP-IPV/Hib combined vaccine replaced them in 2008. The aim of this study was to evaluate the alterations in the frequency of adverse reactions of these different schedules in the consecutive three years.

Methods: A total of 2401 infants who were vaccinated in Gazi University Well Child Clinics during the first 3 months of each schedule were enrolled in the study. Local and systemic adverse events were recorded in diaries by the parents for the next three days.

Results: No significant differences existed between infants vaccinated with DPT + OPV and DPT + OPV + Hib regarding all adverse events detected. Frequency of local and systemic reactions were lower in infants vaccinated with DTaP-IPV/Hib combined vaccine (p < 0.001). Frequency of adverse events in infants vaccinated with DPT + OPV or DPT+ OPV + Hib were highest at booster doses.

Conclusions: The original experience of the study is the demonstration of the adverse event profile for three different schedules which allowed us to draw the profile of the adverse events in a country with changing national schedules. Implementation of Schedule 3 reduced the adverse events of vaccination. Thus reduction in the number of injections and reactogenicity of pertussis vaccine contributed to an increase in the compliance to the vaccination program.