COVID-19, MERS & SARS

In January 2020, a novel coronavirus, SARS-CoV-2, was identified as the cause of an outbreak of viral pneumonia in Wuhan, China. The disease, later named coronavirus disease 2019 (COVID-19), subsequently spread globally. In the first three months after COVID-19 emerged, nearly 1 million people were infected and 50,000 died. By six months the number of cases exceeded 10 million and there were more than 500,000 deaths. To date, there have been roughly 45 million cases and 727,000 deaths from COVID-19 in the United States. One of the troubling observations about COVID-19 is that people who are infected with SARS-CoV-2 – some scientists estimate up to 40% -- can transmit the virus to others before they have symptoms or without ever having symptoms of disease.

NIAID COVID-19 research efforts have built on earlier research on severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), which also are caused by coronaviruses. MERS is a viral respiratory disease that was first reported in Saudi Arabia in September 2012 and has since spread to 27 countries, according to the World Health Organization. Some people infected with MERS coronavirus (MERS-CoV) develop severe acute respiratory illness, including fever, cough, and shortness of breath. Since its emergence in 2021 through August 2021, WHO confirmed 2,578 MERS cases and 888 deaths. Among all reported cases in people, the majority have occurred in Saudi Arabia. Only two people in the United States have tested positive for MERS-CoV, both of whom recovered. They were healthcare providers who lived in Saudi Arabia, where they likely were infected before traveling to the U.S., according to the CDC.

Infection with SARS coronavirus (SARS-CoV) can cause a severe viral respiratory illness. SARS was first reported in Asia in February 2003, though cases subsequently were tracked to November 2002. SARS quickly spread to 26 countries before being contained after about four months. More than 8,000 people fell ill from SARS and 774 died. Since 2004, there have been no reported SARS cases. 

Research evidence suggests that SARS-CoV and MERS-CoV originated in bats. SARS-CoV then spread from infected civets to people, while MERS-CoV spreads from infected dromedary camels to people. To date, the origin of SARS-CoV-2 which caused the COVID-19 pandemic has not been identified. The scientific evidence thus far suggests that SARS-CoV-2 likely resulted from viral evolution in nature and jumped to people or through some unidentified animal host. Public health and scientific organizations are engaged in a continued international effort to uncover the origins of SARS-CoV-2, which is essential to preventing future pandemics.

Unfortunately, because the origins of the SARS-CoV-2 have not yet been identified, misleading and false allegations have been made about NIAID-supported research on naturally occurring bat coronaviruses. Specifically, these allegations have targeted research conducted at the Wuhan Institute of Virology in Wuhan, China, funded through a subaward from NIAID grantee EcoHealth Alliance. The naturally occurring bat coronaviruses studied through this subaward were significantly, genetically different from SARS-CoV-2 and, therefore, could not have caused the COVID-19 pandemic. For a detailed, scientific analysis as to why this is the case, please see: SARS-COV-2 and NIAID-Supported Bat Coronavirus Research.

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