To describe clinical characteristics and hs-CRP, procalcitonin, interleukinee-6 of severe viral pneumonia and co-infection with other viruses or/and bacteria among children under 5 years old at National Hospital of Pediatrics from January, 2015 to March, 2017. | Research on clinical characteristics and hs-CRP, procalcitonin, interleukine 6 in children under 5 years old with severe viral pneumonia and Co-infection