, Lauren Ancel Meyers†‡1
, Danuta M. Skowronski*, Mel Krajden*, David M. Patrick*, and Robert C. Brunham*
Figure 3. . Comparing the effect of face masks for the general public and healthcare workers (HCWs). Mask efficiency is the percent reduction in transmissibility to or from a person correctly using a mask. Compliance is the fraction of the population adopting the intervention. Results are for a mildly contagious disease with a transmissibility T = 0.075 and a moderately contagious disease with a transmissibility T = 0.245. The equivalent basic reproductive number for these diseases are R0 = 1.545 and R0 = 5.047, respectively. Without intervention, both of these diseases have T above the epidemic threshold for the community (Tc = 0.048) and thus may ignite a large-scale epidemic. The probabilities that such epidemics will occur (without intervention) are Sprob = 0.50 and Sprob = 0.97, respectively. Some interventions may not bring T below the epidemic threshold and thus only reduce the probability of an epidemic (gray boxes), while others succeed in containing transmission to a small outbreak (white boxes). Gray boxes give the probability of an epidemic, and white boxes give the expected size of an outbreak. Outbreak size may not be an integer since s is an average taken from all possible outbreaks in the community.