Coronaviruses are a large family of viruses that usually cause mild to moderate upper-respiratory tract illnesses, like the common cold. However, three new coronaviruses have emerged from animal reservoirs over the past two decades to cause serious and widespread illness and death.

There are hundreds of coronaviruses, most of which circulate among such animals as pigs, camels, bats and cats. Sometimes those viruses jump to humans—called a spillover event—and can cause disease. Four of the seven known coronaviruses that sicken people cause only mild to moderate disease. Three can cause more serious, even fatal, disease. SARS coronavirus (SARS-CoV) emerged in November 2002 and caused severe acute respiratory syndrome (SARS). That virus disappeared by 2004. Middle East respiratory syndrome (MERS) is caused by the MERS coronavirus (MERS-CoV). Transmitted from an animal reservoir in camels, MERS was identified in September 2012 and continues to cause sporadic and localized outbreaks. The third novel coronavirus to emerge in this century is called SARS-CoV-2. It causes coronavirus disease 2019 (COVID-19), which emerged from China in December 2019 and was declared a global pandemic by the World Health Organization on March 11, 2020.

Building on previous research on SARS and MERS, NIAID scientists and grantees are well positioned to rapidly develop COVID-19 diagnostics, therapeutics and vaccines. These projects include conducting basic research to understand how the virus infects cells and causes disease, and what interventions can prevent and stop the spread of disease.

In fact, within two weeks of the discovery of COVID-19, NIAID researchers had determined how the virus enters cells. And within two months sites had begun Phase 1 trials of a treatment (remdesivir) and a vaccine (mRNA-1273).

Why Are Coronaviruses a Priority for NIAID?

After SARS-CoV emerged from China in November 2002 it spread to 26 countries within a few months, largely by infected passengers who traveled. More than 8,000 people fell ill and 774 died. SARS drew the collective focus of researchers throughout the world. The disease disappeared in 2004, likely due to intensive contact tracing and case isolation measures. In September 2012, a new coronavirus was identified in the Middle East causing an illness similar to SARS. Again, researchers at NIAID and across the globe initiated studies to understand MERS-CoV and how to stop it. Research efforts from those two outbreaks—including development of a DNA vaccine candidate for SARS by NIAID’s Vaccine Research Center—have prepared scientists to quickly assess the severity and transmission potential of SARS-CoV-2, and to develop countermeasures.

How Is NIAID Addressing This Critical Topic?

When MERS emerged in 2012 and COVID-19 was identified in 2020, NIAID intramural and extramural scientists mobilized quickly to study the viruses, efforts which continue today. Key areas of investigation include basic research on their origins, how they cause disease, and developing animal study models, new treatments, and vaccines.

Volunteer for COVID-19 Clinical Trials

NIAID conducts and supports clinical trials evaluating therapies and vaccine candidates against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), the virus that causes COVID-19.

View a selection of ongoing NIAID-supported COVID-19 studies

Public Health and Government Response to COVID-19

NIAID COVID-19 Strategic Research Plan

The NIAID Strategic Plan for COVID-19 Research details the institute’s priorities for controlling and ultimately ending the spread of the novel coronavirus (SARS-CoV-2) and the disease it causes (COVID-19). The plan focuses on four key research areas to accomplish this.

Read the NIAID 2021 COVID-19 Strategic Research Plan

Antiviral Program for Pandemics

NIAID’s research program to develop safe and effective antivirals to combat SARS-CoV-2 will also build sustainable platforms for targeted drug discovery and development of antivirals against viruses with pandemic potential.

Read about the Antiviral Program for Pandemics

Dr Fauci in the News

Dr. Fauci standing, arms crossed and smiling, in front of a slide with cells on it.

Anthony S. Fauci, M.D., NIAID Director since 1984, has advised eight Presidents on domestic and global health issues like COVID-19 and HIV/AIDS. He is on the White House COVID-19 Response Team.

See a list of articles and interviews with Dr. Fauci

NIH COVID-19 Treatment Guidelines

Transmission electron microscope image of SARS-CoV-2

Expert U.S. panel develops NIH treatment guidelines for COVID-19.

Read the NIH Coronavirus Disease 2019 (COVID-19) Treatment Guidelines

SARS-CoV-2 Assessment of Viral Evolution

The SARS-CoV-2 Assessment of Viral Evolution (SAVE) Program provides a comprehensive real-time risk assessment of SARS-CoV-2 variants and aims to understand how emerging changes in the virus could impact transmissibility, virulence, susceptibility to convalescent and vaccine-induced immunity and diagnostic testing.

Read about the SARS-CoV-2 Assessment of Viral Evolution (SAVE) Program


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.

Read more about COVID-19, MERS & SARS

Therapeutics & Vaccines

NIAID-funded scientists are exploring ways to treat and prevent human coronavirus infections by working to develop new antibodies, drugs, and vaccines. Some block the virus from entering cells, some delay the immune system response, and some block viral replication.

COVID-19 Clinical Research

NIAID is conducting and supporting a range of clinical studies to prevent, treat and better understand both the SARS-CoV-2 coronavirus and the disease it can cause (COVID-19).

Read more about NIAID’s COVID-19 human clinical research

Characterizing Disease

Since the emergence of MERS coronavirus (MERS-CoV) in 2012, NIAID scientists have advanced their understanding of how the virus causes disease, focusing on developing animal models of disease and on countermeasures such as diagnostic tests and vaccine candidates.

Read more about characterizing MERS and COVID-19
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