Facts About Severe Acute Respiratory Syndrome (SARS)

SARS Statistics

• Severe acute respiratory syndrome (SARS) is a new infectious disease first identified in humans in early 2003.

• SARS is caused by a newly described coronavirus, called SARS-associated coronavirus (SARS-CoV). Previously identified human coronaviruses (named for their spiky, crown-like appearance) were known to cause only mild respiratory infections.

• SARS typically begins with flu-like symptoms, including high fever that may be accompanied by headache and muscle aches, cough, and shortness of breath. Up to 20 percent of infected people may develop diarrhea. Most people with SARS subsequently develop pneumonia.

 SARS RESEARCH

The prompt recognition that SARS is caused by a new type of coronavirus is a tribute to the dedication of and collaboration by the world's medical researchers and public health experts. Much more research is needed, however, to develop ways to identify, treat, and prevent this deadly illness.

NIAID scientists, grantees, and industry partners are working to better understand the different aspects of SARS and the virus that causes it. Below are some recent accomplishments and goals for future efforts.

SARS Causes

• Using high-powered microscopes, blood tests, and other standard laboratory techniques, NIAID-supported scientists in Hong Kong were the first to show that SARS was caused by a virus. Within a few days, these scientists and others from CDC showed that the virus was a new and deadly type of coronavirus. These efforts subsequently sparked worldwide efforts to rapidly develop SARS-CoV diagnostic tests, drugs, and vaccines.

• The genetic material, RNA, contained in the SARS-CoV is very difficult to manipulate in the lab. NIAID-funded researchers generated a form of SARS-CoV that is easier to work with. Researchers will be able to use it to study the structure and function of viral proteins, and use the information to develop vaccine candidates.

• An ongoing NIAID-funded program for conducting influenza surveillance in the live bird markets of Hong Kong was expanded to search for animal carriers of SARS-CoV. Researchers traveled to live animal markets in China and determined that some of the samples taken from two animals, the palm civet and the raccoon-dog, were positive for SARS-CoV. These results were the first report of isolation of a SARS-like CoV from animals.

SARS Clinical Trials 

• NIAID has developed a project to study and treat SARS patients, contacts, and health care workers. Should the disease return, these clinical trials would take place at the NIH Clinical Center in Bethesda, Maryland, and would include researching the disease as well as evaluating antiviral and immune-based therapies.

• NIAID, using its Collaborative Antiviral Study Group network of clinical trial sites, is taking the lead in a collaborative effort with the NIH National Heart, Lung, and Blood Institute, CDC, and academic and clinical investigators from the United States and Canada to study experimental SARS therapies. One experimental drug to be evaluated for efficacy is alpha interferon, a drug already approved by the Food and Drug Administration for treating hepatitis B and C infections.

SARS Treatments

• NIAID is participating in a project to screen up to 100,000 antiviral drugs and other compounds for activity against SARS-CoV. While several compounds have shown antiviral activity, only alpha interferon is suitable for immediate clinical evaluation. Several compounds that act by inhibiting the coronavirus cysteine protease enzyme showed a dramatic amount of antiviral activity. These compounds are undergoing preclinical safety evaluations to allow selection of a single candidate for clinical study.

• As more is learned about the mechanisms of SARS-CoV infection, NIAID-supported researchers are beginning to design drugs specifically aimed at its weak points. One such project is developing an "entry inhibitor" that prevents SARS-CoV from infecting human cells.

SARS Tests

Because the symptoms of SARS are similar to those of influenza, clinicians must have fast, accurate tests to identify and, if necessary, isolate people with SARS. NIAID-supported scientists in Hong Kong developed a test that is able to detect the virus in respiratory aspirates (material taken from the lungs and bronchial passages) and in fecal samples.

SARS Vaccines

• Since it is not known which type of vaccine will be most effective against the SARS-CoV, NIAID scientists and grantees are pursuing several parallel approaches in the search for a vaccine.

• In 2003, NIAID awarded contracts to Baxter Healthcare and Sanofi Pasteur to produce experimental inactivated whole virus SARS vaccines and awarded a contract to Protein Sciences Corporation to produce a recombinant subunit vaccine. Once these experimental vaccines are ready, NIAID plans to test them in clinical trials conducted by its Vaccine and Treatment Evaluation Units.

• Scientists at NIAID's Vaccine Research Center developed an experimental SARS vaccine that prevents the SARS-CoV from replicating in laboratory mice. The vaccine was tested on 10 healthy volunteers to determine if it is safe in people and to examine the immune response stimulated (immunogenicity).

SARS Resources 

• To help the world's research community develop an agenda leading to effective control measures for SARS, NIAID convened an international meeting of experts in May 2003.

• Soon after the genetic code for SARS-CoV was determined, NIAID provided interested researchers with free SARS "gene chips" embedded with a reference strain of the virus. With the chip, researchers can rapidly detect genetic variations among SARS strains and could eventually determine which strains are the most dangerous as well as gain other information useful in developing antiviral drugs.

• NIAID has also developed synthetic fragments of key SARS-CoV proteins that are available to SARS researchers. These protein fragments can be used to help understand the immune response to the SARS-CoV.

Reference for Severe Acute Respiratory Syndrome(SARS) Article

National Institutes of Health