Returning to our other outcome variables, while we cannot rule out that the effects of lost health care workers on infant and under-five mortality are zero, confidence intervals suggest an increase in mortality rates. Based on the point estimates, the loss in doctors, nurses, and midwives due to Ebola could lead to increases in infant mortality of 7% in Guinea, 13% in Sierra Leone, and 20% in Liberia, relative to pre-Ebola rates. This would imply an additional 6,700 infant deaths per year across the three countries. For under-five mortality, point estimates suggest increases of 10% in Guinea, 19% in Sierra Leone, and 28% in Liberia, implying an additional 14,100 annual deaths among children under five years old. Aggregating deaths across maternal, infant, and under-five mortality, an additional 24,900 people could die per year as a secondary consequence of Ebola, even after the disease is eliminated.

These mortality estimates may be under- or over-estimated. The cross-country average impact of health care worker supply on maternal, infant, and under-five mortality may be different from the specific impact in Guinea, Liberia, and Sierra Leone. There may be elements of health systems other than health care worker resources – such as their expenditure and geographic distribution of services – which are driving the association with mortality; countries with weak health systems are likely to have both few health care workers and bad health outcomes. This is likely to result in an upward bias of the effect of health care workers on mortality. Unbiased measurement error would bias these estimates toward zero (i.e., attenuation bias). For example, variation in the duration of training, accreditation and classification rules for nurses and midwives across countries means that there is larger heterogeneity in their measurement than in that of doctors, which could potentially mask their true effect on health outcomes.<sup><u>18</u></sup> The fact that significant negative coefficients are found in spite of this bias speaks of their strength and provides support to our estimates. Moreover, these estimates are calculated using data on cumulative health care worker deaths from May 2015. With every day that passes before Ebola is eliminated – which seems to have already come for Liberia, which was declared Ebola free on May 9<sup>th 21</sup> – in which doctors and nurses continue to die from the disease, the effects on non-Ebola mortality will increase.

To put these numbers into context, countries with fewer than 23 doctors, nurses, and midwives per 10,000 of population generally fail to achieve adequate coverage rates for the key primary health interventions prioritized by the Millennium Development Goals.<sup><u>22</u></sup> This is the ratio consistent with having the necessary health care workers to reach 80% coverage of births by skilled attendants. Before Ebola hit, Guinea, Liberia, and Sierra Leone had respective totals of 4·6, 2·4, and 1·9 doctors, nurses, and midwives per 10,000 inhabitants. Accounting for those doctors, nurses, and midwives who have died from the epidemic to date leaves 4·5, 2·2 and 1·8 per 10,000 inhabitants in each country respectively (assuming no additional out-migration as a result of the epidemic). Based on these numbers, in order to fill the health care worker resource gap resulting directly from Ebola, 240 doctors, nurses, and midwives would need to be hired across Guinea, Liberia, and Sierra Leone. But this is in fact a tiny proportion of the necessary health care workers to reach the minimum 80% health coverage targeted by the Millennium Development Goals. To reach those, a 11