Jorge A. Alfaro-Murillo; Alyssa S. Parpia; Meagan C. Fitzpatrick; Jules A. Tamagnan; Jan Medlock; Martial L. Ndeffo-Mbah; Durland Fish; María L. Ávila-Agüero; Rodrigo Marín; Albert I. Ko; Alison P. Galvani

“ Conclusions/Significance Current estimates from our tool suggest that the health burden from microcephaly and GBS warrants substantial expenditures focused on Zika virus control. Our results justify the funding committed in Costa Rica and Brazil and many aspects of the budget outlined in the US president’s proposal. As data continue to be collected, new parameter estimates can be customized in real-time within our user-friendly tool to provide updated estimates on cost-effectiveness of interventions and inform policy decisions in country-specific settings. ”

“ Methodology/Principal Findings Illustrated through an interactive tool, we evaluated how the number of Zika cases averted, the period during pregnancy in which Zika infection poses a risk of microcephaly, and probabilities of microcephaly and Guillain-Barré Syndrome (GBS) impact the cost at which an intervention is cost-effective. From Northeast Brazilian microcephaly incidence data, we estimated the probability of microcephaly in infants born to Zika-infected women (0.49% to 2.10%) . ”

“ The cost-effectiveness of releasing genetically modified male mosquitoes whose offspring die before reaching adulthood depends on the expected Zika attack rate, the effectiveness of prevention, and the country in which the intervention is implemented. ”

“ Our web tool also has the flexibility to adjust the duration of risk during pregnancy, as reports emerge suggesting that the risk could extend beyond early pregnancy.
Birth counts are totaled for the outbreak in Northeast Brazil, where Zika was first confirmed to have reached Latin America in mid-April 2015 [ [1] , [16] ] and where cases have already begun to decline [ [17] ] . Given our assumption that only first-trimester Zika infections can cause microcephaly, we expect Zika-liked microcephaly to begin arising around October 15, 2015, six months after the first infection. ”

“ Indirect costs can be important to assessments of cost-effectiveness from the societal perspective, particularly given that the economic losses for caregivers of children with microcephaly may be substantial. ”

“ If the average life expectancy for these microcephaly cases is lower, interventions aimed at curtailing the ongoing Zika outbreak will avert a greater number of DALYs, since each year of life lost has a higher burden than a year lived with disability. ”

“ Preventing infections in only 1.6% of the population is likely achievable since previous attack rates of Zika virus in Yap Island and French Polynesia have been estimated to range between 62% and 77% [ [15] , [24] ] . ”

“ Interactive Web Tool Our interactive web tool was coded in Python (www.python.org) using the NumPy package for scientific computing (http://www.numpy.org/) and the Bokeh interactive visualization library (http://bokeh.pydata.org/) . ”

“ However, upon inclusion of both direct non-medical costs and productivity losses [ [30] , [31] , [33] ] , the values rise to $736 million in the base case, with $280 million in the most conservative scenario and as high as $1.13 billion in the less conservative scenario. ”