title: Pandemic (H1N1) 2009 virus infection: persistent viral shedding after Oseltamivir treatment.
abstract: OBJECTIVE
  To study pandemic (H1N1) 2009 virological outcomes after Oseltamivir treatment in confirmed cases of pandemic (H1N1) 2009 virus infections. A hospital-based cohort study was conducted in south Thailand, between June and September 2009.
  
  
  METHODS
  Throat/swab specimens were tested by real-time reverse transcriptase polymerase chain reaction (rRT-PCR) for pandemic (H1N1) 2009. All 357 confirmed cases (122 inpatients, 235 outpatients), whose received a 5-day Oseltamivir treatment. Post-treatment virological follow-up was performed in 91 eligible cases. The NA gene was screened for the H275Y mutation responsible for Oseltamivir resistance.
  
  
  RESULTS
  Thirty-three of 91 patients (36%) had underlying diseases. The duration from the onset of illness to the detection of virus ranged 1-14 days (median 3 days). The rRT-PCR was positive on day 5 of treatment in 24 of 91 patients (26%). Patients with underlying diseases had a higher proportion of post-treatment positive test than those without underlying diseases (15/33 vs 9/58). The rRT-PCR-confirmed viruses detected in all 125 throat swab specimens did not show evidence suggesting Oseltamivir resistance.
  
  
  CONCLUSIONS
  Prolonged presence of pandemic (H1N1) 2009 detected by rRT-PCR was found. An extended course of antiviral treatment should be considered in patients with underlying diseases and severe clinical symptoms.
authors.affiliation: Thungsong Hospital, Nakhon Srithammarat, Thailand.
authors.forename: Sawan
authors.initials: S
authors.lastname: Kanchana
authors.forename: Supannakhon
authors.initials: S
authors.lastname: Kanchana
authors.forename: Charas
authors.initials: C
authors.lastname: Chuntrakul
authors.forename: Kumthorn
authors.initials: K
authors.lastname: Malathum
authors.forename: Slinporn
authors.initials: S
authors.lastname: Prachayangprecha
authors.forename: Yong
authors.initials: Y
authors.lastname: Poovorawan
mesh_terms: D000998:Antiviral Agents / Q000008:administration & dosage*; D015331:Cohort Studies; D005500:Follow-Up Studies; D006761:Hospitals; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000188:drug therapy* / Q000821:virology*; D053139:Oseltamivir / Q000008:administration & dosage*; D010614:Pharynx / Q000821:virology; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013785:Thailand; D016896:Treatment Outcome; D017201:Virus Shedding
chemical_list: D000998:Antiviral Agents; D053139:Oseltamivir