This systematic review and meta analysis evaluates the risk factors of COVID-19.

The authors examined 21 clinical and epidemiological studies on confirmed cases of COVID-19 published January 1, 1980 to March 10, 2020. A total of 47,344 (24,419 male and 22,925 female) were included in the meta analysis.

Their main findings include:

• Cases reported to date suggest that most are older adults
• There is no difference in susceptibility between males and females
• Fever is the most common symptom in patients with 2019-nCoV infection
• The most prevalent comorbidities are hypertension and diabetes which are associated with the rapid development of severe illness
• cute respiratory distress syndrome and acute cardiac injury may be the main obstacles for patients to treatment recovery
• The severity and mortality of patients with 2019-nCoV infection is lower than that of Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS), but the prevalence of COVID-19 is much higher than SARS and the MERS