During an outbreak, it is best for children to wear a mask if they go outside; a child-friendly mask is best. If adult masks are worn, cup-shaped masks are not recommended. This is because most of the cup-shaped masks are designed according to the shape of adult’s face, and it is difficult for children to achieve a sealed state, i.e., they cannot achieve the purpose of preventing the transmission of infection. It is more appropriate to choose a flat mask, because most of the cases will not let children go to the place where infectious diseases gather, with ordinary medical masks can be. Medical masks have only three layers, are softer, and the straps can be tightened so that they fit the child’s face when worn. It is not as airtight as a cup mask and is less likely to cause excessive oxygen deprivation in a child. Running and jumping are not recommended for children while wearing the mask and may result in compromised oxygen uptake. Source: Dr. Yurai