Meta-analysis to explain unknown causes of the origins of SARS-COV-2

New Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes the Coronavirus Disease 2019 (COVID-19), an infectious illness that has generated a pandemic crisis worldwide. One of the fundamental questions in science and society is how SARS-CoV-2 has been originated to design best practices directed to prevent and/or to cope with future hazardous pathogens. The study confronts this question here developing a meta-analysis, which endeavors to explain, whenever possible, unknown sources of the SARS-CoV-2. Findings suggest that the natural spillover of novel viral agents that generate more than 6.00 M deaths worldwide in about two years (such as, SARS-CoV-2 from February 2020 to March 2022) has a remote probability of occurrence (using an analogy with the probability of natural disasters generating a lot of fatalities), whereas science advances on hazardous viral agents and consequential lab accident have a (higher) probability of occurrence (about 13-20% like in manifold lab accidents). The findings of this meta-analysis suggest the vital role of improving the technical guidelines of biosafety at all levels in laboratories during the development of scientific research of experimental virology on hazardous pathogens to minimize risks of pandemic threats in environment and human society.