Laboratory Confirmatory Rate of Pandemic Influenza (H1N1 2009) Virus in Korean Households with Index Case / 감염과화학요법

ABSTRACT

BACKGROUND: Influenza transmission in households a subject of renewed interest especially in pandemic situation. We performed this study to investigate the laboratory-confirmatory rate in household contacts with index cases of pandemic influenza (H1N1 2009). MATERIALS AND METHODS: For three months from 1 September and 29 November 2009, people who had a history of close contact with confirmed cases of pandemic influenza (index case) were recruited. The information on the study participants was collected using a standardized questionnaire. Presence of the pandemic influenza (H1N1 2009) infection was confirmed by real-time reverse-transcription polymerase chain reaction (RT-PCR). RESULTS: A total of 113 index cases and 141 household contacts were investigated. One hundred and four index cases (92.0%) were younger than 20 years. The median age of household contacts was 40 years. Twenty eight household contacts (19.8%) had acute respiratory illness (ARI). Overall, 10.6% of enrolled household contacts were positive in RT-PCR for pandemic influenza (H1N1 2009). The positive rate of household contacts with ARI was 25.0% and it was 7.1% in household contacts without ARI. The positive rate was significantly higher in children and young adults under 30 years (28.3%) compared with that in household contacts older than 30 years (8.3%). CONCLUSIONS: This results showed a significant role of mild symptomatic or asymptomatic pandemic influenza (H1N1 2009) patients as a virus carriers in households.