There is a recent paper and a video associated with it that explain how a gas cloud develops through a violent sneeze in a healthy individual. This high-momentum gas cloud could carry the respiratory droplets for long distances (7-8 meters).The video is from  a healthy individual, however it suggests that the potential exposure range to the respiratory droplets of patients with Covid-19 may be larger than 2 meters. Therefore, the recommendations for separation of 3-6 feet (1-2 meters) may not be adequate for reduction of person-to-person transmission of Covid-19 infection. 

This video and the paper shows that the gas clod forming after a violent sneeze in a healthy adult could carry respiratory droplets of varying sizes to a distance of 7-8 meters.
The need for developing a new model for person to person transmission and developing new tests for measuring performance of personal protection equipment (PPE) are highlighted in this paper. 

Paper published in JAMA: The Journal of the American Medical Association March 26, 2020