title: The risk of blood transfusion-associated Chikungunya fever during the 2009 epidemic in Songkhla Province, Thailand.
abstract: BACKGROUND
  Asymptomatic Chikungunya fever (CHIKF)-viremic blood donors could be a potential threat of spreading the disease unwittingly through contaminated blood transfusions. The relatively low prevalence of Chikungunya virus antibodies in the population and the records of more than 9000 suspected CHIKF cases raised concern about the potential transfusion-associated CHIKF during the 2009 epidemic. This study assessed the potential transfusion risk for CHIKF and the implementation of blood safety measures to mitigate this risk.
  
  
  METHODS
  A probabilistic model using key variables obtained from local information was used to estimate the weekly risk of transfusion-associated CHIKF during the 2009 epidemic. In addition, other blood safety measure-based strategies involving screening for donors at risk, donor tracing, and a 7-day quarantine of blood components at risk were implemented at the time of the epidemic.
  
  
  RESULTS
  The risk of viremic donations per 100,000 ranged from 38.2 (95% confidence interval [CI], 36.5-39.8) to 52.3 (95% CI, 50.4-54.2). The potential risk of transfusion-associated CHIKF per 100,000 was estimated to be 1 in 2429 (0.04%; 95% CI, 1 in 6681 [0.02%]-1 in 1572 [0.06%]) to 1 in 1781 (0.06%; 95% CI, 1 in 3817 [0.03%]-1 in 1214 (0.08%]) donations. Among 26,722 donations, 11 (95% CI, 4-17) to 15 (95% CI, 7-22) donations were predicted to associate with transfusion risk. The implementation of blood safety measure-based strategies for this epidemic period suggested to deter 11 blood donations of transfusion risk.
  
  
  CONCLUSIONS
  The interventions for blood safety measures applied in this study had mitigated the potential transfusion-associated CHIKF during the 2009 epidemic.
authors: Department of Pathology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors: Hatsadee
authors: H
authors: Appassakij
authors: Charuporn
authors: C
authors: Promwong
authors: Pairaya
authors: P
authors: Rujirojindakul
authors: Rochana
authors: R
authors: Wutthanarungsan
authors: Khachornsakdi
authors: K
authors: Silpapojakul
mesh_terms: D018354:Alphavirus Infections / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D058070:Asymptomatic Diseases; D001769:Blood / Q000821:virology; D001782:Blood Donors; D001793:Blood Preservation; D058731:Blood Safety / Q000379:methods*; D017848:Blood-Borne Pathogens; D065632:Chikungunya Fever; D002646:Chikungunya virus; D016358:Contact Tracing; D004196:Disease Outbreaks; D046148:Donor Selection; D006801:Humans; D008962:Models, Theoretical; D015995:Prevalence; D011336:Probability; D012306:Risk; D013785:Thailand / Q000453:epidemiology; D013997:Time Factors; D065227:Transfusion Reaction; D014766:Viremia / Q000097:blood / Q000453:epidemiology