COVID-19, the disease that changed the world.

Five years ago, the COVID-19 coronavirus emerged as an invisible threat that profoundly disrupted the world, becoming a public health challenge. The COVID-19 pandemic has shown us how important it is to have health systems that can quickly find and track new viruses as they spread and has ushered in a new era of genomic surveillance, allowing scientists to track the evolution of the coronavirus, providing public health strategies. Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), responsible for the COVID-19 pandemic, has been associated with very important global morbidity and mortality. The discovery of SARS-CoV-2 in bats and pangolins in South Asian countries indicates that SARS-CoV-2 likely originated from wildlife being the third highly pathogenic human coronavirus. The increased contagiousness of SARS-CoV-2 virus was due to the spike glycoprotein (S) that favors the attachment of the virus to the cell surface. SARS-CoV-2 infection triggers a damaging triad of oxidative stress, intense inflammation with cytokine storm, and endothelial dysfunction, leading to widespread cellular damage, blood clotting with thrombosis, and organ failure by overwhelming the body's antioxidant defenses, damaging blood vessel linings, and promoting hyperinflammation, all crucial factors in severe COVID disease. The purpose of the review is to make a synthesis of the data known so far about SARS-CoV-2 virus etiology, the complex interactions between the virus and the host, imbalanced immune response and cytokine storm, molecular mechanisms by which the spike protein drives endothelial dysfunction and, multisystemic pulmonary, cardiovascular, neurological, renal involvement.