Projections of epidemic transmission and estimation of vaccination impact during an ongoing Ebola virus disease outbreak in Northeastern Democratic Republic of Congo, as of Feb. 25, 2019

Worden, Lee; Wannier, Rae; Hoff, Nicole A.; Musene, Kamy; Selo, Bernice; Mossoko, Mathias; Okitolonda-Wemakoy, Emile; Muyembe Tamfum, Jean Jacques; Rutherford, George W.; Lietman, Thomas M.; Rimoin, Anne W.; Porco, Travis C.; Kelly, J. Daniel

On the assumption that past outbreaks provide a basis for projection of the current outbreak, we used estimates of transmission rates from past EVD outbreaks to parameterize simulations of the current outbreak. To estimate the reproduction number R in past outbreaks as a function of the number of days from the beginning of the outbreak, we included reported cases by date from fourteen prior outbreaks (S1 Table) , [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] . To reflect the Ebola response system in DRC during what is now its tenth outbreak, the first historical outbreak reported in each country was excluded (e.g. the 1976 outbreak in Yambuko, DRC), as there is a difference in the Ebola response system as well as community sensitization to EVD following a country's first outbreak. We used the Wallinga-Teunis technique to estimate R for each case and therefore for each reporting date in these outbreaks [31] . The serial interval distribution used for this estimation was a gamma distribution with a mean of 14.5 days and a standard deviation of 5 days, with intervals rounded to the nearest whole number of days, consistent with the understanding that the serial interval of EVD cases ranges from 3 to 36 days with mean 14 to 15 days.