Fractional Dosing of Yellow Fever Vaccine to Extend Supply: A Modeling Study

Wu, Joseph T.; Peak, Corey M.; Leung, Gabriel M.; Lipsitch, Marc

Our results support the growing evidence that dose-sparing strategies should be adopted as an option for extending the currently sparse YF vaccine supply. A Epidemic curve of confirmed cases by dates of symptom onset in Angola and vaccine coverage in Luanda province achieved by the reactive YF vaccination campaign that started on 2 February 2016. 28 The first cases of this YF outbreak were identified in Luanda province which accounted for 90 of the 121 cases confirmed in Angola up to 26 February 2016. B-C Estimates of the daily reproductive number (R t ) assuming that the mean mosquito lifespan was 7 and 14 days, respectively. The red data points correspond to the cases that were used to estimate the initial reproductive number. These cases had symptom onset one mean serial interval before the vaccination campaign began to affect disease transmission (which was assumed to be 7 days after the start of the campaign to account for the time it takes for adaptive immunity to develop). The orange and purple horizontal bars indicate the length of the mean mosquito lifespan and serial interval on the scale of the xaxis, respectively.