Depends on virus. Rsv is a virus that can vary in its effect on an infected child from a simple runny nose to life threatening pneumonia.The smaller the infant/kid the worse the potential pbs.Kids catch this virus almost every year but seldom have problems after infancy.Other forms of viral pneumonia vary in their outcome. The worst i've known was chickenpox pn in a untreated newborn delivered by a midwife.(died).
Compared. Compared to what? Usually it is not that bad but the extreme of the range is death fortunately very rare.
It depends. Pneumonias (both viral and bacterial) can be dangerous at both extremes of age - very young ages (<2) & the elderly. Certain underlying lung & heart conditions can increase the risk of having severe disease, especially in young children that were born premature. Please ensure that children & their caregivers wash hands regularly & receive flu vaccine. Prevention is better than cure.