Incidence of hypotonic-hyporesponsive episodes associated to the combined DTP/Hib vaccine used in Brazilian National Immunizations Program

Objective: To evaluate the safety of a combined diphtheria-tetanus-whole cell pertussis-Haemophilus influenzae type b vaccine used on the Brazilian National Immunizations Program, chiefly the incidence of hypotonic-hyporesponsive episodes. Method: Follow-up of a cohort of 21,064 infants (20,925 or 99.7% adhered to the study protocol), within 48 hours of vaccination with diphtheria-tetanus-whole cell pertussis-Haemophilus influenzae type b vaccine in health care units in the City of Rio de Janeiro, to ascertain and investigate spontaneous and solicited severe adverse events. Each child was followed-up for one dose only. Results: The rate of hypotonic-hyporesponsive episodes was 1/1,744 doses (confirmed cases) and 1/1,495 doses (confirmed plus suspect cases). The rate of convulsions was 1/5,231 doses. No cases of apnea were detected. These results are comparable to those found in the literature with diphtheria-tetanus-whole cell pertussis vaccine. Conclusion: The diphtheria-tetanus-whole cell pertussis-Haemophilus influenzae type b vaccine under study can be safely used in the National Immunizations Program, according to the current precautions and contra indications.