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Last reviewed
May 5, 2021

Coronavirus Overview

Human coronaviruses were cultured in the 1960s from nasal cavities of people with the common cold, reported a recent study. Coronaviruses are the 2nd leading cause of the common cold after rhinoviruses. 

People commonly get infected with human coronaviruses 229E, NL63, OC43, and HKU1 says the U.S. CDC.

There are four main sub-groupings of coronaviruses, known as alpha, beta, gamma, and delta. Beta coronaviruses are microscopic balls covered in spikes that encapsulate a central core of genetic material. The virus must infect cells to replicate and do this, and it must first attach to the cells.

The International Committee for the Taxonomy of Viruses has approved the naming of more than 40 coronaviruses.

Both the Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS) are betacoronavirus and have their origins in bats. MERS (ongoing) and SARS-1 (2003) have been known to cause severe illness in humans.

On January 9, 2020, China's CDC reported a novel coronavirus as the causative agent of the new coronavirus outbreak, which is phylogenetically in the SARS-CoV clade. This novel coronavirus has been named ‘severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), while the human disease it causes has been classified by the WHO as COVID-19 disease.

SARS-CoV-2 Coronavirus

The current outbreak of the novel coronavirus SARS-CoV-2 originated in 2019 but has now spread internationally, impacting most countries, says the CDC.

On February 5, 2020, JAMA published a new study from genetic sequencing data, showing this coronavirus shares 79.5% of the genetic sequence with SARS-CoV-1 and has 96.2% homology to a bat coronavirus. This indicates SARS-CoV-1 and SARS-CoV-2 are not the same coronaviruses.

SARS-CoV-1 Coronavirus

SARS-CoV-1 was the first major novel infectious disease to hit the international community in the 21st century, says the U.S. CDC. SARS was first reported in Asia in February 2003 and became a notifiable disease in mid-April in central China. By the time the outbreak was contained in July 2003, SARS had affected 8,098 people in 29 countries and resulted in 774 deaths, reported GAVI.

MERS-CoV Coronavirus

The emergence of the betacoronavirus Middle East Respiratory Syndrome (MERS) was first reported in the Kingdom of Saudi Arabia in 2012. Humans are infected with MERS-CoV from direct or indirect contact with dromedaries. MERS-CoV has demonstrated the ability to transmit between humans.

So far, the observed non-sustained human-to-human transmission has occurred mainly in healthcare settings, says the WHO.

Relevant Coronavirus Links

Note: This content is sourced from the U.S. CDC, the WHO, research studies, and is reviewed by health professionals, such as Dr. Robert Carlson.