| Methods |
Prospective cohort study of 9 observations (3 each when using 3 different masks). The authors observed and photographed droplet dispersal while a volunteer breathed out 3 times in 3 different types of mask |
| Participants |
1 volunteer |
| Interventions |
Three masks, 2 without air filter and allowing external exhalation, 1 with manifold and air filter |
| Outcomes |
Effectiveness: plume of droplets as observed and photographed: masks were poor at preventing droplet spread |
| Notes |
Risk of bias: low
Notes: the authors conclude that the mask with manifold and air filter did not allow dispersal of droplets and was far safer in an epidemic such as SARS to contain the spread. Simple, safe and effective study |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
N/A |
| Allocation concealment (selection bias) |
Unclear risk |
N/A |
| Blinding (performance bias and detection bias)
All outcomes |
Unclear risk |
N/A |
| Incomplete outcome data (attrition bias)
All outcomes |
Unclear risk |
N/A |
| Selective reporting (reporting bias) |
Unclear risk |
N/A |
