Epidemiology of COVID-19

In the last days of December 2019, in a seafood market in Wuhan, China, an outbreak of pneumonia of unknown origin was identified and later reported to the World Health Organization (WHO) regional office through the International Health Regulations for its dissemination to WHO member countries. The WHO declared the outbreak of a Public Health Emergency of International Concern (PHEIC) on January 30th, and on March 11th, 2020, the WHO Director-General declared it a pandemic. Today, it has been spread to more than 200 countries. The SARS-CoV-2 pandemic could be considered the health event with the greatest impact worldwide in the last 100 years. As of March 11th, 2021, one year later, more than 17 million cases and 2,615,018 deaths have been registered. The clinical picture caused by SARS-CoV-2 ranges from mild to severe forms. Some require hospitalization and, in some cases, even treatment in Intensive Care Units is needed due to multiorgan disease. Medium and long-term sequelae are still under investigation. The pandemic has affected health services in Mexico and all over the world, not only due to the hospital reconversion for the care of patients with COVID-19 in the face of the emergency, but also because the care of patients with other conditions has been delayed with a negative impact on the physical and mental health of populations. Likewise, it has deranged several social activities such as travel, commerce, and education.

Keywords: Severe acute respiratory syndrome, antigens, antibodies, COVID-19, coronavirus, epidemic, epidemiology, fatality, mortality, outbreak, pandemic, PHEIC, population, preventive measures, SARS-CoV-2, spike protein, vaccines, zoonosis.