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Volume 17, Number 10—October 2011

Research

Pandemic (H1N1) 2009 among Quarantined Close Contacts, Beijing, People’s Republic of China

Xinghuo Pang1, Peng Yang1, Shuang Li, Li Zhang, Lili Tian, Yang Li, Bo Liu, Yi Zhang, Baiwei Liu, Ruogang Huang, Xinyu Li, and Quanyi WangComments to Author 

Author affiliations: Beijing Center for Disease Prevention and Control, Beijing, People’s Republic of China; Capital Medical University School of Public Health and Family Medicine, Beijing

Main Article

Table 1

Timeliness and intensity of contact tracing for pandemic (H1N1) 2009, Beijing, People’s Republic of China*

Contact type Median no. days (range)
Hours from interview of index case-patient to quarantine of close contacts, % (no./total no.)†
First exposure to quarantine† Last exposure to quarantine† Illness onset
to sample collection‡ Generation time‡§
<24 >24–48 >48–72 >72
All close contacts 41.3 (69/167) 26.3 (44/167) 21.6 (36/167) 10.8 (18/167) 3.4 (0.2–8.1) 1.9 (0.1–6.8) 0.5 (−4.5 to 5.0) 2.4 (0.2–6.8)
Flight passenger contacts 60.7 (17/28) 28.6
(8/28) 10.7
(3/28) 0
(0/28) 1.7 (0.2–5.6) 1.2 (0.2–3.8) 0.4 (−1.0 to 1.9) 1.6 (0.3–4.8)
Nonpassenger contacts 37.4 (52/139) 25.9 (36/139) 23.7 (33/139) 12.9 (18/139) 3.8 (0.2–8.1) 1.9 (0.1–6.8) 0.6 (−4.5 to 5.0) 2.5 (0.2–6.8)

*Data available for those who were infected because more detailed information was collected in field records.
†Data for close contacts infected with pandemic (H1N1) 2009 influenza.
‡Data for symptomatic close contacts infected with pandemic (H1N1) 2009 influenza virus. Negative values indicate that the time of sample collection was before that of illness onset.
§Generation time is time from illness onset in an index case-patient to illness onset in a secondary case-patient.

*Data available for those who were infected because more detailed information was collected in field records.
†Data for close contacts infected with pandemic (H1N1) 2009 influenza.
‡Data for symptomatic close contacts infected with pandemic (H1N1) 2009 influenza virus. Negative values indicate that the time of sample collection was before that of illness onset.
§Generation time is time from illness onset in an index case-patient to illness onset in a secondary case-patient.

*Data available for those who were infected because more detailed information was collected in field records.
†Data for close contacts infected with pandemic (H1N1) 2009 influenza.
‡Data for symptomatic close contacts infected with pandemic (H1N1) 2009 influenza virus. Negative values indicate that the time of sample collection was before that of illness onset.
§Generation time is time from illness onset in an index case-patient to illness onset in a secondary case-patient.

Main Article

1These authors contributed equally to this article.

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