title: Assessment of the risk of ebola importation to australia.
abstract: OBJECTIVE
  To assess the risk of Ebola importation to Australia during the first six months of 2015, based upon the current outbreak in West Africa.
  
  
  METHODS
  We assessed the risk under two distinct scenarios: (i) assuming that significant numbers of cases of Ebola remain confined to Guinea, Liberia and Sierra Leone, and using historic passenger arrival data into Australia; and, (ii) assuming potential secondary spread based upon international flight data. A model appropriate to each scenario is developed, and parameterised using passenger arrival card or international flight data, and World Health Organisation case data from West Africa. These models were constructed based on WHO Ebola outbreak data as at 17 October 2014 and 3 December 2014. An assessment of the risk under each scenario is reported. On 27 October 2014 the Australian Government announced a policy change, that visas from affected countries would be refused/cancelled, and the predicted effect of this policy change is reported.
  
  
  RESULTS
  The current probability of at least one case entering Australia by 1 July 2015, having travelled directly from West Africa with historic passenger arrival rates into Australia, is 0.34. Under the new Australian Government policy of restricting visas from affected countries (as of 27 October 2014), the probability of at least one case entering Australia by 1 July 2015 is reduced to 0.16. The probability of at least one case entering Australia by 1 July 2015 via an outbreak from a secondary source country is approximately 0.12.
  
  
  CONCLUSIONS
  Our models suggest that if the transmission of Ebola remains unchanged, it is possible that a case will enter Australia within the first six months of 2015, either directly from West Africa (even when current visa restrictions are considered), or via secondary outbreaks elsewhere. Government and medical authorities should be prepared to respond to this eventuality. Control measures within West Africa over recent months have contributed to a reduction in projected risk of a case entering Australia. A significant further reduction of the rate at which Ebola is proliferating in West Africa, and control of the disease if and when it proliferates elsewhere, will continue to result in substantially lower risk of the disease entering Australia.
authors: School of Mathematical Sciences, The University of Adelaide, Adelaide, South Australia, Australia.
authors: Robert C
authors: RC
authors: Cope
authors: School of Earth & Environmental Sciences, The University of Adelaide, Adelaide, South Australia, Australia.
authors: Phillip
authors: P
authors: Cassey
authors: Geography, Environment and Population, The University of Adelaide, Adelaide, South Australia, Australia.
authors: Graeme J
authors: GJ
authors: Hugo
authors: School of Mathematical Sciences & NHMRC CRE in Infectious Diseases Modelling to Inform Public Health Policy, Th University of Adelaide, Adelaide, South Australia, Australia.
authors: Joshua V
authors: JV
authors: Ross
keywords: Australia; Ebola virus; Policy; Risk; ebola