Why is viral pneumonia less serious than bacterial pneumonia(which can cause a pulmonary abscess)? I mean what if you are infected by multiple viruses for some reason or another. This makes the whole viral infection more serious than if you were infected by a single bacterium. Also while babies might not often get bacterial infections, they often have the most serious cases of any infection because they have less antibodies against it than everybody else does. This makes even the common cold more serious in babies since it can lead to an even more serious infection with viral pneumonia, especially from the flu virus which has symptoms that can start as soon as 4 hours after the infection starts and is a common culprit for viral pneumonia. And the common cold is a filtrable virus(meaning it can pass through porcelain easily) so it itself could potentially get to the lungs and cause pneumonia.