Beyond the Routine Influenza Surveillance

Choi, Sang-Ho

Another focus of the study by Kang et al. was the risk factor analysis for modified SARI and pneumonia. Significant risk factors included old age and various underlying chronic disorders. Influenza vaccination was the only significant protective factor for pneumonia. The mean age of patients diagnosed with modified SARI and pneumonia was 61.6 and 68.5 years, respectively. Of them, <50% of patients received influenza vaccination before the onset of influenza season. Considering the recent influenza vaccination rate of >75% in Korean elderly people [5] , this finding indirectly reemphasizes the importance of influenza vaccination in elderly and comorbid patients. The risk ratios for SARI and pneumonia sharply increased as the number of concurrent chronic medical conditions increased. As this study was performed in tertiary care hospitals only, there may be some selection bias associated with recruiting sites. That is, as the authors described, a large proportion of patients had underlying chronic disorders, which may affect the results. The absence of data regarding intensive care unit admission and mortality limits the comparison with other reports.