Giuseppe
Emeritus
Abstract. Neuraminidase Inhibitor Resistance after Oseltamivir Treatment of Acute Influenza A and B in Children - Clinical Infectious Diseases
Clinical Infectious Diseases 2009;48:000?000
? 2009 by the Infectious Diseases Society of America. All rights reserved.
1058-4838/2009/4804-00XX$15.00
MAJOR ARTICLE
Neuraminidase Inhibitor Resistance after Oseltamivir Treatment of Acute Influenza A and B in Children
Iain Stephenson,(1) Jane Democratis,(1) Angie Lackenby,(2) Teresa McNally,(1) James Smith,(3) Manish Pareek,(1) Joanna Ellis,(2) Alison Bermingham,(2) Karl Nicholson,(1) and Maria Zambon(2)
1) Infectious Diseases Unit, Leicester Royal Infirmary, Leicester, and 2) Health Protection Agency, Colindale, London, United Kingdom; and 3) Pharmaceutical Division, Hoffman LaRoche, Basel, Switzerland
Background.
Oseltamivir, a specific influenza neuraminidase inhibitor, is an effective treatment for seasonal influenza. Emergence of drug-resistant influenza viruses after treatment has been reported, particularly in children in Japan, where the dosing schedule is different from that used throughout the rest of the world. We investigated the emergence of drug-resistant infection in children treated with a tiered weight-based dosing regimen.
Methods.
We analyzed sequential clinical nasopharyngeal samples, obtained before and after tiered weight-based oseltamivir therapy, from children with acute influenza during 2005?2007. We isolated viruses, tested for drug resistance with use of a fluorescence-based neuraminidase inhibition assay, performed neuraminidase gene sequencing, and determined quantitative viral loads.
Results.
Sixty-four children (34 with influenza A subtype H3N2, 11 with influenza A subtype H1N1, and 19 with influenza B virus) aged 1?12 years (median age, 3 years, 1 month) were enrolled. By days 4?7 after initiation of treatment, of 64 samples tested, 47 (73.4%) and 26 (40.6%) had virus detectable by reverse-transcriptase polymerase chain reaction and culture, respectively. By days 8?12 after initiation of treatment, of 53 samples tested, 18 (33.9%) and 1 (1.8%) had virus detectable by reverse-transcriptase polymerase chain reaction and culture, respectively. We found no statistically significant differences in the reduction of viral shedding or time to clearance of virus between viral subtypes. Antiviral-resistant viruses were recovered from 3 (27.3%) of 11 children with influenza A subtype H1N1, 1 (2.9%) of 34 children with influenza A subtype H3N2, and 0 (0%) of 19 children with influenza B virus, all of whom were treated with oseltamivir ( ) There was no evidence of prolonged illness in children infected with drug-resistant virus.
Conclusions.
Drug resistance emerges at a higher rate in influenza A subtype H1N1 virus than in influenza A subtype H3N2 or influenza B virus after tiered weight-based oseltamivir therapy. Virological surveillance for patterns of drug resistance is essential for determination of antiviral treatment strategies and for composition of pandemic preparedness stockpiles.
Received 19 August 2008; accepted 29 September 2008; electronically published 9 January 2009.
* (See the editorial commentary by Monto on pages XXX?XXX)
Reprints or correspondence: Dr. Iain Stephenson, Infectious Diseases Unit, Windsor Bldg., Leicester Royal Infirmary, Leicester, LE1 5WW, United Kingdom (iain.stephenson@uhl-tr.nhs.uk).
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<cite cite="http://www.journals.uchicago.edu/doi/abs/10.1086/596311">Chicago Journals - Clinical Infectious Diseases</cite>? 2009 by the Infectious Diseases Society of America. All rights reserved.
1058-4838/2009/4804-00XX$15.00
MAJOR ARTICLE
Neuraminidase Inhibitor Resistance after Oseltamivir Treatment of Acute Influenza A and B in Children
Iain Stephenson,(1) Jane Democratis,(1) Angie Lackenby,(2) Teresa McNally,(1) James Smith,(3) Manish Pareek,(1) Joanna Ellis,(2) Alison Bermingham,(2) Karl Nicholson,(1) and Maria Zambon(2)
1) Infectious Diseases Unit, Leicester Royal Infirmary, Leicester, and 2) Health Protection Agency, Colindale, London, United Kingdom; and 3) Pharmaceutical Division, Hoffman LaRoche, Basel, Switzerland
Background.
Oseltamivir, a specific influenza neuraminidase inhibitor, is an effective treatment for seasonal influenza. Emergence of drug-resistant influenza viruses after treatment has been reported, particularly in children in Japan, where the dosing schedule is different from that used throughout the rest of the world. We investigated the emergence of drug-resistant infection in children treated with a tiered weight-based dosing regimen.
Methods.
We analyzed sequential clinical nasopharyngeal samples, obtained before and after tiered weight-based oseltamivir therapy, from children with acute influenza during 2005?2007. We isolated viruses, tested for drug resistance with use of a fluorescence-based neuraminidase inhibition assay, performed neuraminidase gene sequencing, and determined quantitative viral loads.
Results.
Sixty-four children (34 with influenza A subtype H3N2, 11 with influenza A subtype H1N1, and 19 with influenza B virus) aged 1?12 years (median age, 3 years, 1 month) were enrolled. By days 4?7 after initiation of treatment, of 64 samples tested, 47 (73.4%) and 26 (40.6%) had virus detectable by reverse-transcriptase polymerase chain reaction and culture, respectively. By days 8?12 after initiation of treatment, of 53 samples tested, 18 (33.9%) and 1 (1.8%) had virus detectable by reverse-transcriptase polymerase chain reaction and culture, respectively. We found no statistically significant differences in the reduction of viral shedding or time to clearance of virus between viral subtypes. Antiviral-resistant viruses were recovered from 3 (27.3%) of 11 children with influenza A subtype H1N1, 1 (2.9%) of 34 children with influenza A subtype H3N2, and 0 (0%) of 19 children with influenza B virus, all of whom were treated with oseltamivir ( ) There was no evidence of prolonged illness in children infected with drug-resistant virus.
Conclusions.
Drug resistance emerges at a higher rate in influenza A subtype H1N1 virus than in influenza A subtype H3N2 or influenza B virus after tiered weight-based oseltamivir therapy. Virological surveillance for patterns of drug resistance is essential for determination of antiviral treatment strategies and for composition of pandemic preparedness stockpiles.
Received 19 August 2008; accepted 29 September 2008; electronically published 9 January 2009.
* (See the editorial commentary by Monto on pages XXX?XXX)
Reprints or correspondence: Dr. Iain Stephenson, Infectious Diseases Unit, Windsor Bldg., Leicester Royal Infirmary, Leicester, LE1 5WW, United Kingdom (iain.stephenson@uhl-tr.nhs.uk).
-