The next time you buy disposable masks, read the label on the box, which states, “This mask does not eliminate the risk of contracting any disease or infection.” On boxes of surgical masks read, “Single use surgical masks are intended to be worn to protect both the patient and the healthcare personnel from the transfer of microorganisms, body fluids, and particulate material. These masks are intended for use in infection control practice to reduce the potential exposure to blood and bodily fluids.”
Therefore, wearing a mask is of limited use when dealing with a virus or other airborne disease and more of a placebo than anything else. However, if it makes you feel safe, wear one.