SARS (Severe Acute Respiratory Syndrome): Complete Guide to Symptoms, Causes, Diagnosis & Treatment

5 days ago

9 min read

Updated: 2 days ago

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026

TL;DR: SARS (severe acute respiratory syndrome) is a contagious respiratory illness caused by the SARS-CoV-1 coronavirus, which first appeared in November 2002 and spread worldwide within months. It usually starts with flu-like symptoms such as fever, chills, and muscle aches, then progresses to dry cough and shortness of breath after about a week. A global public health effort stopped the spread, and no cases have been reported anywhere in the world since 2004. There is no effective treatment, so hospital care focuses on easing symptoms with IV fluids and oxygen.

Quick Answer: What Is SARS?

SARS is a serious, contagious illness of the lungs and airways caused by a coronavirus called SARS-CoV-1. It first appeared in November 2002, spread mainly through close personal contact, and reached multiple countries within months. SARS typically begins with fever of 100.4°F (38°C) or higher, chills, muscle aches, and headache, and often progresses to dry cough and shortness of breath after about a week. Thanks to a coordinated global response, no cases of SARS have been reported anywhere in the world since 2004.

Key Fact	Detail
What it is	A contagious respiratory illness (disease of the lungs and airways)
Cause	SARS-CoV-1, a strain of coronavirus
First appeared	November 2002; spread worldwide within a few months
How it spreads	Mainly close personal contact; also contaminated surfaces
Last known cases	No cases reported anywhere in the world since 2004
Most common symptoms	Fever 100.4°F (38°C) or higher, chills, muscle aches, headache; later dry cough and shortness of breath
Effective treatment	None found yet; care eases symptoms (IV fluids, oxygen)
Prevention today	No tested human vaccine; handwashing, gloves, masks, surface disinfection if cases return

What Is SARS?

SARS is a contagious illness caused by a coronavirus. It is a disease that affects the lungs and airways, which is why it is also called a respiratory illness. The coronavirus that causes SARS is called SARS-CoV-1.

The virus first appeared in November 2002. Within a few months, the SARS-CoV-1 virus spread worldwide. It mainly passed from person to person.

A global effort from health experts quickly stopped the spread of the disease. No cases of SARS have been reported anywhere in the world since 2004.

SARS Symptoms

SARS usually starts with flu-like symptoms. The early signs include fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher, chills, muscle aches, and headache. Diarrhea is sometimes present as well.

After about a week, the illness can progress. Symptoms at this stage can include a dry cough and shortness of breath.

Stage	Symptoms
Usually at the start (flu-like)	Fever of 100.4°F (38°C) or higher; chills; muscle aches; headache
Sometimes at the start	Diarrhea
After about a week	Dry cough; shortness of breath

When to See a Doctor

SARS is a serious illness that can lead to death. If you have any symptoms of a respiratory infection, call a member of your healthcare team right away.

Also call your health professional if you have flu-like symptoms with a fever after you travel abroad.

What Causes SARS?

SARS is caused by SARS-CoV-1, a strain of coronavirus. Coronaviruses are the family of viruses that also cause the common cold.

A different strain of coronavirus, called SARS-CoV-2, causes COVID-19. The two are related strains within the same virus family but cause different diseases.

Coronaviruses can cause serious disease in animals. That is why scientists suspect that the SARS-CoV-1 virus might have started in animals and crossed to humans. It now seems likely that one or more animal viruses evolved into the new strain.

Cause Question	Answer
What virus causes SARS?	SARS-CoV-1, a strain of coronavirus
What virus family is it in?	Coronaviruses — the same family that causes the common cold
What causes COVID-19?	SARS-CoV-2, a different coronavirus strain
Where did SARS-CoV-1 likely come from?	It likely evolved from one or more animal viruses and crossed to humans

How the SARS Virus Spreads

Most viruses that cause respiratory illnesses, including SARS, spread when infected people cough, sneeze, or talk. Tiny liquid particles from the nose or mouth enter the air, and healthy people nearby breathe in those particles.

Most experts think the virus that causes SARS spreads mainly through close personal contact. For instance, a healthy person could get infected while taking care of someone who has SARS.

The virus also can spread on objects such as doorknobs, telephones, and elevator buttons. Touching an object that has the virus on it and then rubbing the nose, eyes, or mouth could cause an infection.

Spread Route	How It Happens
Close personal contact	Main route; for example, caring for someone who has SARS
Airborne particles	Coughing, sneezing, or talking releases tiny liquid particles that nearby people breathe in
Contaminated surfaces	Virus on doorknobs, phones, or elevator buttons; infection occurs by touching these, then the nose, eyes, or mouth

SARS Risk Factors

By and large, people at greatest risk of SARS are those who have had direct, close contact with someone who's infected. This includes healthcare workers and family members living with someone who has SARS.

Risk Factor	Why It Raises Risk
Close contact with an infected person	The virus spreads mainly through direct, close personal contact
Healthcare workers	Caregiving involves prolonged close exposure to infected patients
Family members at home	Living with someone who has SARS means repeated close contact

SARS Complications

Many people with SARS get pneumonia. And sometimes, a machine called a ventilator is needed to help with breathing.

SARS is fatal in some cases, often because the body can't get enough oxygen or can't remove enough carbon dioxide. This condition is called respiratory failure. SARS also can lead to heart and liver failure.

The risk of getting very sick from SARS rises with age, especially in people older than 60. The risk also goes up if you have another long-term health condition, such as diabetes or chronic hepatitis B.

Complication	Detail
Pneumonia	Develops in many people with SARS
Respiratory failure	The body can't get enough oxygen or remove enough carbon dioxide; a leading cause of SARS deaths
Heart failure	Can result from severe illness
Liver failure	Can result from severe illness
Ventilator use	Sometimes needed to help with breathing
Higher-risk groups	People older than 60; people with long-term conditions such as diabetes or chronic hepatitis B

How Is SARS Diagnosed?

When SARS first appeared, no specific tests checked for it. Now various tests can help detect the virus. These include tests of the blood, stool, nose, and throat.

No known spread of the virus that causes SARS has happened anywhere in the world since 2004.

Diagnostic Test	Sample Used
Blood test	Blood
Stool test	Stool
Nose test	Nasal sample
Throat test	Throat sample

SARS Treatment

Scientists haven't yet found an effective treatment for SARS. And antiviral medicines that clear up infections caused by viruses haven't shown much benefit. Antibiotic medicines only work against bacteria, not viruses.

Hospital care for SARS involves easing symptoms while the SARS virus runs its course. Care might include receiving fluids through a vein and extra oxygen if needed.

Treatment Approach	How It Works
Effective cure	None found so far
Antiviral medicines	Haven't shown much benefit against SARS
Antibiotics	Only work against bacteria, not viruses
Hospital care	Eases symptoms while the virus runs its course
IV fluids	Fluids given through a vein
Extra oxygen	Given if breathing support is needed
Ventilator	A machine that may be needed to help with breathing in severe cases

How to Prevent SARS

Researchers are working on various vaccines for SARS. But none has been tested in humans. If infections caused by the SARS virus happen again, following some safety measures is key, especially if you care for someone who may have SARS.

Wash your hands. Clean your hands often with soap and hot water. Or use an alcohol-based hand rub made with at least 60% alcohol.

Wear disposable gloves. Put them on if you might have contact with an infected person's body fluids or feces. Throw the gloves away right after you use them. Then wash your hands well.

Wear a surgical mask. Use it to cover your mouth and nose when you're in the same room as a person with SARS. Or you could wear a device called an N95 respirator, which can also help block the spread of the SARS virus. Wearing eyeglasses may offer some protection too.

Wash personal items. Use soap and hot water to wash the utensils, towels, bedding, and clothing of someone with SARS.

Disinfect surfaces. Use a household disinfectant. Clean any surfaces that may have been in contact with sweat, saliva, mucus, vomit, stool, or urine. Wear disposable gloves while you clean. Throw the gloves away when you're done. Then wash your hands.

Follow these steps for at least 10 days after the person's fever has gone away and any breathing symptoms have gotten better. Health authorities recommend that an infected person stay home from work or school during this time. Call your healthcare team right away if a fever or other symptoms start within 10 days of close contact with someone who has SARS.

Prevention Step	How to Do It
Handwashing	Wash often with soap and hot water, or use an alcohol-based hand rub with at least 60% alcohol
Disposable gloves	Wear when contact with body fluids or feces is possible; discard immediately after use, then wash hands
Surgical mask or N95 respirator	Cover mouth and nose when in the same room as someone with SARS; eyeglasses may offer some protection
Wash personal items	Soap and hot water for utensils, towels, bedding, and clothing
Disinfect surfaces	Household disinfectant on surfaces touched by sweat, saliva, mucus, vomit, stool, or urine; wear disposable gloves
Duration of precautions	At least 10 days after fever is gone and breathing symptoms have improved; stay home from work or school

Conclusion

SARS is a serious, contagious respiratory illness caused by the SARS-CoV-1 coronavirus. It typically begins with flu-like symptoms — fever of 100.4°F (38°C) or higher, chills, muscle aches, and headache — and can progress after about a week to dry cough and shortness of breath. The virus spreads mainly through close personal contact and can also live on contaminated surfaces. People in direct, close contact with infected individuals, especially healthcare workers and family members at home, face the greatest risk, and severe illness is more likely in people over 60 and those with long-term conditions like diabetes or chronic hepatitis B. A coordinated global health response stopped the spread, and no cases have been reported anywhere in the world since 2004. Today, there is no effective treatment and no vaccine tested in humans, so hospital care focuses on easing symptoms with IV fluids and oxygen while the virus runs its course.

Take the next step: If you develop flu-like symptoms with a fever after traveling abroad, or any symptoms of a respiratory infection, call your healthcare team right away.

Frequently Asked Questions

1. What is SARS and what causes it?

SARS (severe acute respiratory syndrome) is a contagious respiratory illness that affects the lungs and airways. It is caused by SARS-CoV-1, a strain of coronavirus in the same family as the viruses that cause the common cold. A different strain, SARS-CoV-2, causes COVID-19. Scientists believe SARS-CoV-1 likely started in animals and crossed to humans.

2. What are the symptoms of SARS?

SARS usually starts with flu-like symptoms: fever of 100.4°F (38°C) or higher, chills, muscle aches, headache, and sometimes diarrhea. After about a week, symptoms can include a dry cough and shortness of breath.

3. Is SARS still a threat today?

No known spread of the virus that causes SARS has happened anywhere in the world since 2004. A global effort from health experts quickly stopped the spread after the virus appeared in November 2002 and circulated worldwide within months.

4. How does SARS spread?

SARS spreads mainly through close personal contact, such as caring for someone who has the illness. Infected people release tiny liquid particles when they cough, sneeze, or talk, and nearby people can breathe them in. The virus can also live on objects such as doorknobs, telephones, and elevator buttons; touching a contaminated surface and then the nose, eyes, or mouth can cause infection.

5. Who is at highest risk of getting SARS?

People who have had direct, close contact with someone who is infected are at greatest risk. This includes healthcare workers and family members living with someone who has SARS.

6. Can SARS be fatal?

SARS is a serious illness that can lead to death. Many people with SARS develop pneumonia, and some need a ventilator to help with breathing. Deaths often occur because the body cannot get enough oxygen or remove enough carbon dioxide, a condition called respiratory failure. SARS can also lead to heart and liver failure.

7. How is SARS diagnosed and treated?

Blood, stool, nose, and throat tests can now detect the SARS-CoV-1 virus. Scientists have not yet found an effective treatment. Antiviral medicines have not shown much benefit, and antibiotics only work against bacteria, not viruses. Hospital care eases symptoms with IV fluids and extra oxygen while the virus runs its course.

8. Is there a vaccine for SARS?

Researchers are working on various vaccines for SARS, but none has been tested in humans. If infections happen again, key prevention measures include handwashing, disposable gloves, surgical masks or N95 respirators, washing personal items, and disinfecting surfaces for at least 10 days after symptoms improve.