Evaluation of Timeliness of Palivizumab Immunoprophylaxis Based on the Epidemic Period of Respiratory Syncytial Virus: 22 Year Experience in a Single Center

ABSTRACT

PURPOSE: This study aimed to analyze the epidemic period of RSV infection and evaluate the appropriate time of palivizumab immunoprophylaxis. METHODS: From January 1991 to July 2012, nasopharyngeal (NP) aspirates were obtained from patients who visited Seoul National University Children's Hospital for respiratory symptoms. NP samples were used to detect respiratory viruses. Among them, we analyzed the positive number and detection rate of RSV infection in two-week interval. The beginning of RSV season was defined when RSV positive number was more than 4 and RSV detection rate was over 10%. From January 2007 to March 2014, we analyzed the starting time of palivizumab immunoprophylaxis for the infants at high risk. RESULTS: The RSV detection rate was 2,013/21,698 (9.69%) over 22 years. The median RSV season was from 2nd-3rd week of October to 1st- 2nd week of February. The earliest starting week was the 3rd week of July in year 2001, and the latest end week was the 3rd week of May in year 1990. Palivizumab immunoprophylaxis was initiated most frequently at the 3rd week of October (18.7%). However, the percentage of starting palivizumab on the 1st week of September has increased from 3.8% in the year 2007 to 14.1% in 2013. CONCLUSIONS: The year to year variability of RSV season exists. The starting time of palivizumab immunoprophylaxis should be adjusted based on the season of RSV epidemic.