Development of a New WHO Guideline on Ventilation for Better Infection Control in Hospitals

Abstract:

During and since the 2003 SARS epidemic, we have attempted to understand how expiatory droplets dry up and disperse, and how to use building ventilation to minimize the exposure of the droplet nuclei in hospitals particularly in isolation rooms. In collaboration with medical collaborators, we have learned through our research how airflow and ventilation affected SARS and influenza transmission in a number of outbreaks in Hong Kong and Beijing, the right negative pressure and the optimum ventilation method to be used in isolation rooms, how droplets dry out in air, how cough works, and why the Grantham Hospital in Hong Kong has been naturally ventilated since 1957 etc.

During 2003, we constructed a six-bed SARS ward test room in collaboration with the HKIE SARS Busters to demonstrate the basic principle of isolation ventilation to hundreds of medical doctors, nurses, engineers, health officials and media from Hong Kong and Asia. We subsequently assisted WHO in drafting the ventilation chapter of the 2007 Interim infection control guideline, and the TB control guideline. Finally, we led and developed the new 2009 WHO natural ventilation control guidelines, which have been particularly useful for application in resource-limited countries.