Abstract
Objective
To characterize adverse events following immunization in children under one year old.
Methods
Cross-sectional study conducted with data from the Brazilian Notification System on Adverse Events Following Immunization between 2009 and 2013.
Results
A total of 810 cases were analyzed, with a rate of 6.76 adverse events per 100,000 doses. Adverse events were related to the tetravalent (45.1%) and pentavalent (37.4%) vaccines, and associated with age, dosage, time elapsed from immunization, and adopted course. Hypotonic-hyporesponsive episode (27.0%) was the most prevalent event (p<0.001).
Conclusion
Adverse events were more frequent in children younger than three months that received the first dose of the tetravalent and pentavalent vaccines; they occurred within the first twenty-four hours following immunization, and the prevalent course consisted in changing the immunization schedule.
Vaccination/adverse effects; Prevalence; Immunization schedule; Child