title: Stability and infectivity of novel pandemic influenza A (H1N1) virus in blood-derived matrices under different storage conditions.
abstract: BACKGROUND
  Influenza A virus has been detected in the blood of some infected individuals, and may pose a safety concern for collection, handling and transport of specimens for epidemiological and public health investigations if infectious virus is present in samples. Furthermore the effect of storage on virus stability and infectivity has not been well studied.
  
  
  METHODS
  We examined the stability of novel pandemic influenza A (H1N1) virus RNA when the virus was stored in phosphate buffered saline (PBS), plasma, or buffy coated blood at either room temperature or 4°C using a sensitive Taqman RT-PCR assay. We also investigated virus infectivity using the EID(50) assay when virus was stored in PBS, plasma, or buffy coats isolated from blood at 4°C.
  
  
  RESULTS
  Viral RNA stability was affected by the matrix used for storage. The recovery of viral RNA was highest when virus was stored in PBS with lower amounts being recovered from plasma and buffy coats at either room temperature or 4°C. Incubation time did not appear to be a major factor for viral RNA stability, although there was gradual decline after longer periods post-incubation. Both sample matrix and incubation time affected virus infectivity. The decay in virus infectivity was greatest in PBS followed by buffy coats and plasma. Virus infectivity was abolished in buffy coats at day 20 post-incubation when virus concentrations were low.
  
  
  CONCLUSIONS
  These data indicate that encapsidated viral RNA was stable overall in all three liquid matrices at room temperature or 4°C although it was most stable in PBS; virus infectivity in buffy coats at 4°C decayed in a time dependent manner while it remained unchanged in plasma. These findings have implications for storage, handling and transport of blood derived samples from influenza patients for epidemiological and laboratory investigations. It should be noted that there is little known about influenza viremia, and whether influenza viruses can be transmitted by blood or blood derived samples.
authors.affiliation: Laboratory of Molecular Virology, Division of Emerging and Transfusion Transmitted Diseases, CBER/FDA, Bethesda, MD 20892, USA. xue.wang@fda.hhs.gov
authors.forename: Xue
authors.initials: X
authors.lastname: Wang
authors.forename: Olga
authors.initials: O
authors.lastname: Zoueva
authors.forename: Jiangqin
authors.initials: J
authors.lastname: Zhao
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Ye
authors.forename: Indira
authors.initials: I
authors.lastname: Hewlett
mesh_terms: D001769:Blood / Q000821:virology*; D002021:Buffers; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity*; D007251:Influenza, Human / Q000175:diagnosis*; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D012034:Refrigeration; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013048:Specimen Handling / Q000379:methods*; D013997:Time Factors
chemical_list: D002021:Buffers; D012367:RNA, Viral