Infect Chemother.  2010 Apr;42(2):82-86.

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

• Kim HL
• Jeon HH
• Kim M
• Kang CH
• Park KH

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.

Keyword

Household; Pandemic influenza (H1N1 2009); RT-PCR

MeSH Terms

Child
Family Characteristics
Humans
Influenza, Human
Pandemics
Polymerase Chain Reaction
Viruses
Young Adult
Surveys and Questionnaires

Figure

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  Figure 1 Positive rates in RT-PCR according to age groups of enrolled household contacts. The rate of positive results in RT-PCR is significantly higher in children and young adults, and there is no positive case in people over 50 years. Numbers on the bar represent the ratio of positive cases to total cases. RT-PCR, reverse-transcription polymerase chain reaction.

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