Epidemiology and Infection

Influenza H1N1 and other respiratory infections

Delayed oseltamivir treatment is associated with longer viral shedding of pandemic (H1N1) 2009 virus

Y. H. LEUNGa1 c1, W. L. LIMa2, M. H. WONGa1 and S. K. CHUANGa1

a1 Field Epidemiology Training Programme, Centre for Health Protection, Department of Health, Hong Kong, People's Republic of China

a2 Public Health Laboratory Services Branch, Centre for Health Protection, Department of Health, Hong Kong, People's Republic of China

SUMMARY

During the early phase of the influenza pandemic in 2009, all cases of laboratory-confirmed pandemic (H1N1) 2009 (pH1N1) infection required compulsory isolation in hospital. These cases were offered oseltamivir treatment and only allowed to be discharged from the hospital when three consecutive respiratory specimens were negative for the virus by reverse transcription–polymerase chain reaction (RT–PCR). We reviewed the case records of these patients to assess the viral shedding kinetics of the pH1N1 virus. We defined viral shedding duration as the interval from illness onset date to the date of collection of the last positive specimen from the patients. Fifty-six patients were included in the study, of whom 96% received oseltamivir. The median viral shedding duration of pH1N1 virus by viral culture and RT–PCR were 3 days and 4 days, respectively. Patients who started oseltamivir treatment >48 h after onset had a significantly longer median viral shedding duration by viral culture than those who started treatment within 48 h of onset (4 days vs. 2 days, P=0·014).

(Accepted June 29 2011)

(Online publication July 29 2011)

Correspondence:

c1 Author for correspondence: Y. H. Leung, Field Epidemiology Training Programme, Centre for Health Protection, Department of Health, Room 325, 147C Argyle Street, Kowloon, Hong Kong. (Email: mo_fetp1@dh.gov.hk)

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