Unless you are already infected, face masks won’t helpFace masks have become a symbol of coronavirus, but stockpiling them might do more harm than good. First, they don’t do much to protect you. Most surgical masks are too loose to prevent inhalation of the virus. (Masks can help prevent the spread of a virus if you are infected. The most effective are the so-called N95 masks, which block 95 percent of very small particles.)Second, health care workers and those caring for sick people are on the front lines. Last month, the surgeon general urged the public to stop stockpiling masks, warning that it might limit the amount of resources available to doctors, nurses and emergency professionals.