OBJECTIVE: To evaluate the impact of the ministerial statement of vaccination against influenza in healthy infants in the age group of 6 and 24 months since 2006.
MATERIAL AND METHODS: Retrospective review of medical records of patients hospitalized due to respiratory infection caused by influenza virus between January 2004 and December 2007 at the Hospital Roberto del Río. All cases were confirmed by positive immunofluorescence for influenza virus A or B.
RESULTS: Of a total of 224 patients, 122 are from the pre-vaccination period (2004-2005) and 102 from post vaccination period (2006-2007). The hospitalization rate was similar during the study time course. During the post vaccination period only 4 of 102 patients received vaccination, meanwhile 68% of them were out of age requirements for the vaccination ministerial campaign. 70% of hospitalized patients are younger than 2 years in both groups. There were not significant differences in sex, hospital stay, oxygen requirements, ICU admission or in the need of invasive mechanical ventilation. 75% of hospitalized patients did not exhibit comorbility. These results show a change in the seasonal pattern of influenza infections after the vaccine introduction that remains all over the years.
CONCLUSIONS: There is not a decrease in the hospitalization rate or a change in the clinical characteristics of hospitalized patients after the vaccine introduction. There is a clear change in the seasonal distribution with a curve flattening, unlike the classic outbreak presentation described in literature and observed in our country prior to this program.
KEY WORDS: influenza, influenza vaccination, children, hospitalization. |
