Background: To identify alarming symptoms that could potentially lead to severe form of COVID-19 pneumonia (i.e. novel coronavirus pneumonia: NCP), a disease that is now having pandemic spread. Methods: Articles from PubMed, Embase, Cochrane database and Google up to 24 February 2020 were systematically reviewed. 18 publications that had documented cases of COVID-19 pneumonia were identified. The relevant data were extracted, systematically reviewed and further evaluated using meta-analysis. We define severe COVID-19 pneumonia as the disease status that requires admission to the intensive care unit (ICU) and respiratory/circulatory support, which is in align with the guideline from the World Health Organization (WHO). Results: 14 studies including 1,424 patients were considered eligible and analyzed. Symptoms such as fever (89.2%), cough (67.2%), fatigue (43.6%) were quite common; but dizziness, hemoptysis, abdominal pain and conjunctival congestion/conjunctivitis were relatively rare. The incidence of dyspnea was significantly higher in patients with severe than non-severe COVID-19 pneumonia (42.7% vs.16.3%, p<0.0001). Similarly, fever and diarrhea were also drastically more common in patients with severe form (p=0.0374 and 0.0267). Further meta-analysis using three high-quality China-based studies confirmed such findings and showed that dyspnea, fever and diarrhea were 3.53 (OR: 3.53, 95%CI: 1.95-6.38), 1.70 (OR: 1.70, 95%CI: 1.01-2.87), and 1.80 (OR: 1.80, 95%CI: 1.06-3.03) folds higher respectively in patients with severe COVID-19 pneumonia. Conclusion: Dyspnea, fever and diarrhea are significantly more prevalent in patients with severe COVID-19 pneumonia, suggesting they are alarming symptoms that warrant close attention and timely management.