Retrospective versus real-time Ebola virus sequencing

The 2018 Democratic Republic of the Congo EVD outbreak was the ninth recorded in the country. 54 cases were reported with 33 fatalities, resulting in a case fatality rate of approximately 60%, which is in line with that of the much larger 2013–16 west African outbreak. The 2013–16 west African outbreak was associated with more than 28 000 cases of EVD, which resulted in more than 11 000 fatalities.3 Permission from local government to ship samples to Europe and North America enabled early mass sequence analysis by the European mobile laboratory (EMLab)4 and others,5 which revealed important factors about the timing of the initial spillover event, mutation rate, suitability of available medical countermeasures, and the transmission dynamics during the first year of the outbreak. A subsequent review of approximately 2000 sequences from the outbreak provided greater insight into contributions of geographical, political, economic, and social factors on transmission throughout the region.6 When we presented our retrospective sequence analysis of 180 EBOV genomes from the first year of the west African outbreak4 to Guinean and WHO officials in Conakry, Guinea, in March 2015, we and response leaders quickly realised the true value of sequencing data to support epidemiology.