16 June 2020 PAHO’s Smart Hospitals Project started in 2009 and has been implemented across nine countries in the Caribbean Region. The onset of the COVID-19 pandemic has introduced new lessons to be incorporated as part of Smart Retrofits. This document is intended to describe simple natural and mechanical ventilation measures which can be implemented as an extension of the PAHO Smart Retrofits with the aim of reducing the risk of transmission of viruses like COVID-19.