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May 12, 2022

Severe Acute Respiratory Syndrome (SARS-1)

According to the U.S. CDC, the beta coronavirus that causes severe acute respiratory syndrome-1 (SARS-1) is a viral respiratory illness caused by a human coronavirus (hCoV) called SARS-associated coronavirus (SARS-CoV).

SARS-1 originated in Guangdong Province, located in southern China, in November 2002 and was brought to Hong Kong in February 2003. From Hong Kong, the disease spread rapidly worldwide but primarily to Asian countries. At the end of the SARS-1 epidemic in 2004, the global cumulative total was 8,422 cases with 916 deaths (case fatality rate of 11%). 

SARS-1 is a different coronavirus than the SARS-CoV-2, which was identified in 2019. The new SARS-CoV-2 coronavirus and variants are more infectious but less fatal than its forerunner, SARS-CoV-1.

SARS-1 Outbreak Timeline

2003 - As of July 2003, the WHO reported 325 SARS-1 cases, and the illness spread to about 24 countries in North America, South America, Europe, and Asia 2003.

2003 - There have been six escapes from virology labs: 1 event each in Singapore and Taiwan and four separate escapes of the coronavirus at the same laboratory in Beijing, China.

2004 - The WHO published the 'SARS Risk Assessment and Preparedness Framework during October.' And the CDC issues a "Notice of Embargo of Civets." A SARS-like virus had been isolated from civets (captured in China's areas where the SARS outbreak originated). As a result, CDC banned the importation of civets, which remains in effect.

2005 - A pre-clinical study found chloroquine effectively inhibits SARS-CoV infection and spreads in cell culture. Similar studies describe these proteins' roles in SARS-CoV replication and potential therapeutic strategies to prevent SARS-CoV entry into target cells.

2005 - Microbiologist Kwok-yung Yuen of the University of Hong Kong and colleagues sampled monkeys, rodents, and bat species in Hong Kong's hinterlands. The SARS-like virus was found in 39% of the anal swabs collected from Chinese horseshoe bats, both eaten and used in traditional Chinese medicine. Also, around 80% of serum samples collected from the bats showed antibodies to the virus.

SARS-CoV Research

From 2007-to 2017, there were two dozen incidents at US-based labs involving influenza, SARS, and MERS, according to Lynn Klotz, a senior science fellow at the Center for Arms Control and Non-Proliferation, and shared with the Monitor. Ten of those incidents occurred at UNC-Chapel Hill, involving SARS and featuring a range of scenarios.

In November 2015, the journal Nature Medicine published a study: 'A SARS-like cluster of circulating bat coronaviruses shows potential for human emergence. Furthermore, the study abstract stated, 'Our work suggests a potential risk of SARS-CoV re-emergence from viruses currently circulating in bat populations.'. This study used metagenomics data to identify a potential threat posed by the circulating bat SARS-like CoV SHC014. Because of the ability of chimeric SHC014 viruses to replicate in human airway cultures, cause pathogenesis in vivo and escape current therapeutics, there is a need for both surveillance and improved therapeutics against circulating SARS-like viruses.

SARS-CoV Overview

Human coronavirus was initially cultured in the 1960s from people with the common cold nasal cavities, reports a recent study. They are the 2nd leading cause of the common cold after rhinoviruseAccording to the CDC, people worldwide commonly get infected with human coronaviruses 229E, NL63, OC43, and HCDC. The discovery of bat SARS-like coronaviruses and the great genetic diversity of coronaviruses in bats have shed new light on SARS coronaviruses' origin and transmission.

There are four main sub-groupings of coronaviruses, known as alpha, beta, gamma, and delta. SARS-CoV is a betacoronavirus, like MERS.

The incubation period for SARS is typically 2 to 7 days, although it may be as long as ten days in some cases. In a tiny proportion of patients, incubation periods of up to 14 days have been reported. The WHO estimates that the SARS case fatality ratio ranges from 0% to 50%, depending on the age group affected.

During the SARS-1 outbreak in 2004 in China, SARS-CoV RNA was detected in 100% of untreated and 30% of disinfected wastewater samples collected from a hospital in Beijing, China receiving SARS patients (Wang et al., 2005). 

The U.S. CDC published a report in December 2006 that concluded 'Bats have been identified as a natural reservoir for an increasing number of emerging zoonotic viruses, including henipaviruses and variants of rabies viruses. Recently, another group independently identified several horseshoe bat species as the reservoir host for many viruses with a close genetic relationship with the coronavirus associated with severe SARS. In addition to SARS-like coronaviruses, many other novel bat coronaviruses, which belong to groups 1 and 2 of the three existing coronavirus groups, have been detected by PCR.

SARS-CoV Sources

A 2015 study suggests a potential risk of SARS-CoV re-emergence from viruses currently circulating in bat populations. The results indicate that group 2b viruses encoding the SHC014 spike in a wild-type backbone can efficiently use multiple orthologs of the SARS receptor human angiotensin-converting enzyme II (ACE2), replicate efficiently in primary human airway cells, and achieve in vitro titers equivalent to epidemic strains of SARS-CoV. A study published in 2007 found horseshoe bats are a natural reservoir for the SARS-CoV-like virus.

NOTE: This page's content is sourced from the CDC, WHO,, and the Precision Vax news network. Healthcare providers last fact-checked this information.