The Comparison of the Adverse Events of Pentavalent Vaccine and DPT Vaccine in 2-6 Months Infants in Iran: A National Study.

Vaccination is the most remarkable intervention in public health and is an effective strategy in controlling infectious diseases among infants.The aim of this study was to compare the adverse events of Pentavalent vaccine and DPT vaccine in two- to six-month-old infants in Iran.This is an analytical cross-sectional study in which healthy infants aged two to six months, having received DPT vaccine in 2013 and Pentavalent vaccine in 2015, were studied for any experienced adverse events related to these vaccines. Percentage, mean, standard deviation and chi-square tests were used to describe and analyze the data (p < 0.05).The results showed that 10,464 and 17,561 adverse events, which were associated with DPT vaccine and Pentavalent vaccine respectively, were recorded in the infants who received these vaccines throughout Iran. Mazandaran, Qazvin and Golestan provinces reported the highest number of adverse events, respectively (15.74%, 11.25%, and 9.12%). Moreover, Pentavalent vaccine seemed to have more recorded adverse events compared to DPT, high fever had the highest record rate for DPT vaccine (47.4%) and mild localized complications was the highest for Pentavalent vaccines (31.68%). There was a significant relationship between the kind of vaccine and the type of reaction, adverse event categorization and the country that produced the vaccine (p < 0.05).Severe localized adverse events including high fever, vomiting, diarrhea and restlessness seemed to be less in Pentavalent vaccine compared to DPT vaccine. Therefore, substituting Pentavalent vaccine for DPT vaccine in infants seems to reduce the adverse events among them.