Surgical masks can really prevent the spread of disease is a rather disappointing 'kind of'. Many studies have shown that masks do reduce the amount of bacteria shed into the air when we cough, talk or sneeze and this has even been shown to work within households.However a mask will still only catch a percentage of those germs, and as such it's still important to put your hand in front of your mouth. If wearing a surgical mask means someone stops putting their hand in front when they sneeze or cough, then it may actually be counter-productive and have a detrimental effect rather than a positive one. And if holding your hand in front can catch a greater proportion of the bacterial droplets, then you may as well just do that. Likewise, while a mask might block some of the larger bacteria from getting in, you'll still be susceptible to many types of disease. And let's not forget that a little bacteria is no bad thing for our immune systems which need to be given a chance to flex their muscles from time to time to stay strong.In short a wearing a facemask can protect you from various diseases to a great extent.