Abstract: We quantify the macroeconomic effects of COVID-19 for a small open economy by calibrating a SIR-multi-sector-macro model to Turkey. Sectoral supply shocks are based on the proximity requirements in each sector and the ability to work from home. Physical proximity determines the supply shock through its effect on infection rates. Sectoral demand shocks incorporate domestic and foreign demand, both of which adjust with infection rates. We calibrate demand shocks during COVID-19 using real-time credit card purchase data. Our results show that the optimal policy, which yields the lowest economic cost and saves the maximum number of lives, can be achieved under a full lockdown of 39 days. Economic costs are much larger for an open economy as the shocks are amplified through the international production network. A decline in foreign demand leads to losses in domestic sectors through international input-output linkages, accounting for a third of the total output loss. In addition, the reduction in capital flows deprives the network from its trade financing needs, where sectors with larger external finance needs experience larger losses. The policy options are limited given sparse fiscal resources to fight the pandemic domestically, while serving the external debt. We present historical evidence from 2001 crisis of Turkey, when fiscal, monetary and exchange rate policies were employed altogether to deal with a triple crisis of balance of payments, banking, and sovereign debt