In this paper numerical transient simulations were used to investigate the air flow patterns distribution and velocity and the particulate dispersion inside an existing typical hospitalization room equipped with an advanced Heating Ventilation Air Conditioning (HVAC) with Variable Air Volume (VAV) primary air system designed for immune-suppressed patients never modelled before The three-dimensional models of the room consider different most typical positions of the patients Results indicate the best conditions for the high induction air inlet diffuser and the scheme of pressures imposed in the room to provide the effective means of controlling flows containing virus droplets We believe that our work exemplifies the usefulness of numerical investigations of HVAC performances in real situations and provides important recommendations towards disease control and careful design and optimization of ventilation in hospital settings (C) 2010 Elsevier B V All rights reserved