Severe Acute Respiratory Syndrome: Symptoms, Treatments, Medications and Prevention

by topschoolsintheusa · Published October 31, 2024 · Updated September 14, 2024

Severe Acute Respiratory Syndrome (SARS) is a viral respiratory illness caused by the SARS-associated coronavirus (SARS-CoV). This disease garnered worldwide attention during the 2002-2003 outbreak that originated in southern China, spreading to multiple countries and leading to a global health crisis. SARS primarily affects the respiratory system, with symptoms ranging from mild to severe respiratory distress, and it has a relatively high mortality rate compared to other coronaviruses.

What is Severe Acute Respiratory Syndrome (SARS)?

Severe Acute Respiratory Syndrome (SARS) is a highly contagious viral illness caused by a specific type of coronavirus known as SARS-CoV. Coronaviruses are a large family of viruses that cause illnesses ranging from the common cold to more severe diseases like Middle East Respiratory Syndrome (MERS) and COVID-19. SARS-CoV is zoonotic, meaning it is transmitted from animals to humans, with evidence suggesting that the original transmission occurred from bats to humans via an intermediate host, such as civet cats.

SARS-CoV infects the respiratory tract, causing inflammation in the lungs and potentially leading to severe respiratory distress. The virus spreads primarily through respiratory droplets when an infected person coughs or sneezes. It can also spread via close contact, contaminated surfaces, and, in some cases, through airborne transmission in confined spaces.

The SARS outbreak in 2002-2003 was a significant global health event, infecting over 8,000 people across 29 countries and resulting in 774 deaths. The World Health Organization (WHO) declared SARS a global public health threat, and by 2004, the outbreak was contained through public health interventions such as quarantine, isolation, and travel restrictions. Since then, there have been no reported cases of SARS, but the virus remains a significant concern due to its potential for re-emergence.

Who is at Risk of Severe Acute Respiratory Syndrome?

While SARS is no longer circulating globally, the populations most at risk during outbreaks are similar to those vulnerable to other viral respiratory infections. Several factors determine the risk of contracting SARS, including geographic location, healthcare exposure, and the overall health of individuals.

Populations at Higher Risk

1. Healthcare Workers

During the 2002-2003 outbreak, healthcare workers were at a particularly high risk of contracting SARS due to their close and prolonged contact with infected patients. Hospitals and healthcare facilities became hotspots for transmission as the virus spread from patients to doctors, nurses, and other medical staff. Inadequate protective measures, such as the lack of personal protective equipment (PPE), contributed to the high transmission rate in these settings.

2. Close Contacts of Infected Individuals

Individuals who live with or provide care for SARS patients are also at high risk of infection. The virus spreads primarily through respiratory droplets and direct contact with contaminated surfaces, making household transmission a significant concern. Family members, caregivers, and anyone in close proximity to an infected person are more likely to contract the virus.

3. Older Adults

Older adults, particularly those over 60, were at higher risk for severe illness and death during the SARS outbreak. As with many respiratory illnesses, aging weakens the immune system, making it harder for the body to fight off infections like SARS-CoV. Additionally, older adults are more likely to have underlying health conditions that increase their vulnerability to respiratory complications.

4. Individuals with Pre-existing Health Conditions

People with underlying medical conditions such as heart disease, chronic lung disease, diabetes, or weakened immune systems are at a greater risk of severe illness if they contract SARS. These conditions can impair the body’s ability to fight the infection and increase the likelihood of complications such as pneumonia or respiratory failure.

5. Travelers to Affected Areas

During the initial SARS outbreak, individuals traveling to or residing in areas with active transmission were at an elevated risk. International travelers, especially those passing through affected regions, were at risk of contracting the virus and unknowingly spreading it to other locations. Airports and public transportation hubs played a role in the global spread of SARS during the 2002-2003 outbreak.

Symptoms of Severe Acute Respiratory Syndrome

SARS symptoms typically develop 2 to 10 days after exposure to the virus, with an average incubation period of 4 to 6 days. The illness progresses through two phases, beginning with flu-like symptoms and potentially escalating to severe respiratory distress.

Early Symptoms (Prodromal Phase)

During the early stages of infection, SARS presents with non-specific symptoms that resemble the flu or other common respiratory illnesses. This phase is often referred to as the prodromal phase, and the symptoms may last several days before the disease progresses.

Common Early Symptoms Include:

Fever: A high fever, often above 100.4°F (38°C), is usually the first noticeable symptom of SARS.
Chills and Muscle Aches: Many patients experience chills, sweating, and muscle pain (myalgia), similar to flu-like symptoms.
Headache: A persistent headache is a common early symptom.
Fatigue and Malaise: Generalized fatigue and weakness are prominent, with many patients feeling unusually tired and lethargic.
Loss of Appetite: Patients often lose their appetite during the early stages of infection.
Sore Throat and Mild Respiratory Symptoms: Some individuals develop a sore throat or mild cough, but these symptoms may not be prominent at this stage.

Advanced Symptoms (Respiratory Phase)

As SARS progresses, the virus begins to severely affect the respiratory system, leading to more serious symptoms. This second phase is marked by significant respiratory distress, and in some cases, the illness can progress to life-threatening conditions.

Severe Symptoms Include:

1. Dry Cough

A dry, non-productive cough is one of the most common symptoms of advanced SARS. It usually develops after the initial flu-like symptoms and worsens over time.

2. Shortness of Breath (Dyspnea)

Shortness of breath becomes more pronounced as the virus causes inflammation in the lungs, leading to decreased oxygen exchange. Patients may experience difficulty breathing and feel as if they cannot take in enough air.

3. Pneumonia

As SARS progresses, many patients develop viral pneumonia, where the alveoli (air sacs) in the lungs fill with fluid, reducing their ability to absorb oxygen. Pneumonia is diagnosed through imaging tests like chest X-rays, which often show infiltrates or consolidation in the lungs.

4. Hypoxemia (Low Oxygen Levels)

Low blood oxygen levels are a hallmark of severe SARS. Hypoxemia can lead to cyanosis (bluish discoloration of the lips and extremities), indicating that the body is not receiving adequate oxygen.

5. Acute Respiratory Distress Syndrome (ARDS)

In severe cases, SARS can lead to Acute Respiratory Distress Syndrome (ARDS), a life-threatening condition in which the lungs become unable to provide sufficient oxygen to the rest of the body. ARDS requires immediate medical intervention and often leads to the need for mechanical ventilation.

6. Organ Failure

As oxygen levels drop and the body struggles to cope with the infection, some patients may experience multi-organ failure, particularly of the heart, kidneys, and liver. This complication increases the risk of death.

How is Severe Acute Respiratory Syndrome Diagnosed?

Diagnosing SARS involves a combination of clinical evaluation, laboratory tests, and imaging studies. Early detection is essential for preventing the spread of the virus and for initiating appropriate treatment to improve patient outcomes.

Diagnostic Methods for Severe Acute Respiratory Syndrome

1. Clinical Evaluation and Patient History

The first step in diagnosing SARS is a thorough clinical evaluation, including taking a detailed patient history. Healthcare providers will assess symptoms such as fever, cough, and shortness of breath, while also considering whether the patient has had recent contact with confirmed SARS cases or traveled to areas where SARS is known to be present. Given the flu-like nature of early symptoms, SARS can be difficult to differentiate from other viral respiratory illnesses without further testing.

2. Laboratory Testing

Once SARS is suspected, laboratory tests are used to confirm the diagnosis. These tests include:

Polymerase Chain Reaction (PCR) Test: PCR is a molecular test used to detect the genetic material of the SARS coronavirus (SARS-CoV) in respiratory secretions, such as nasal or throat swabs. PCR is highly sensitive and specific, making it the gold standard for diagnosing SARS.
Serology Tests: Serological tests detect antibodies (IgM and IgG) to SARS-CoV in the patient’s blood. IgM antibodies typically appear within the first week of infection, while IgG antibodies appear later, indicating a more prolonged or past infection.
Viral Culture: In some cases, healthcare providers may attempt to grow the virus in a laboratory culture to confirm its presence. However, this method is less commonly used due to the availability of faster molecular techniques like PCR.

3. Chest X-rays and CT Scans

Chest imaging plays a critical role in diagnosing and assessing the severity of SARS, particularly in cases where pneumonia or ARDS is suspected. Common findings on chest X-rays and CT scans include:

Bilateral Infiltrates: The appearance of hazy or white areas in both lungs, indicative of fluid accumulation (pneumonia).
Ground-glass Opacities: A diffuse, cloud-like appearance in the lungs, commonly seen in viral pneumonias and ARDS.

4. Blood Tests

Blood tests may be ordered to assess the patient’s overall health and organ function. Common blood tests include:

Complete Blood Count (CBC): A CBC can reveal low white blood cell counts (leukopenia) and low platelet counts (thrombocytopenia), both of which are associated with SARS.
Liver and Kidney Function Tests: These tests help monitor organ function, as SARS can lead to liver and kidney damage in severe cases.

Differential Diagnosis

Since the early symptoms of SARS are non-specific, the disease must be differentiated from other respiratory illnesses, including:

Influenza (Flu)
COVID-19
Community-acquired pneumonia
Other coronaviruses like Middle East Respiratory Syndrome (MERS)

Laboratory tests, patient history, and imaging help differentiate SARS from these other conditions.

Treatments for Severe Acute Respiratory Syndrome

There is no specific antiviral treatment for SARS, and management primarily focuses on supportive care to alleviate symptoms and prevent complications. Early intervention is critical to improving survival rates, particularly for patients who progress to severe respiratory illness.

Supportive Care

1. Oxygen Therapy

Patients with SARS who develop respiratory symptoms, such as shortness of breath or hypoxemia, may require supplemental oxygen. Oxygen can be delivered through:

Nasal Cannula or Oxygen Mask: For patients with mild to moderate respiratory distress.
Mechanical Ventilation: In cases of severe respiratory failure or ARDS, patients may need mechanical ventilation to assist with breathing. Mechanical ventilators help maintain adequate oxygenation when the lungs can no longer function on their own.

2. Intensive Care and Monitoring

Patients with severe SARS often require admission to an intensive care unit (ICU) for continuous monitoring and supportive care. Intensive care may include:

Fluid Management: Maintaining proper hydration while avoiding fluid overload is critical for patients with pneumonia or ARDS.
Hemodynamic Support: Patients in shock or with low blood pressure may require medications, such as vasopressors, to stabilize their blood pressure.

3. Antipyretics and Pain Management

Fever and body aches are common symptoms of SARS. Over-the-counter medications like acetaminophen or ibuprofen are used to reduce fever and alleviate muscle pain and discomfort.

4. Antibiotics (For Secondary Infections)

While antibiotics are not effective against the SARS virus, they may be prescribed if there is a concern about secondary bacterial infections, such as bacterial pneumonia, which can occur in immunocompromised patients or those with severe disease.

Experimental Treatments

During the 2002-2003 outbreak, several experimental treatments were used in an attempt to manage SARS, although none were proven to be definitively effective. Some of these include:

1. Antiviral Drugs

Certain antiviral drugs, such as ribavirin, were used during the SARS outbreak. However, clinical trials did not demonstrate a clear benefit, and ribavirin has significant side effects, including anemia. Other antivirals, such as lopinavir/ritonavir, typically used to treat HIV, were also tested but with limited success.

2. Corticosteroids

Corticosteroids, such as dexamethasone or methylprednisolone, were sometimes used to reduce inflammation in the lungs, particularly in patients with severe ARDS. However, the use of corticosteroids in viral infections like SARS is controversial because they can suppress the immune system and potentially worsen outcomes.

3. Convalescent Plasma Therapy

Convalescent plasma, which involves transfusing plasma from recovered SARS patients into those currently battling the virus, was used as an experimental treatment. The theory behind this therapy is that the antibodies in the plasma can help neutralize the virus. However, more research is needed to determine its efficacy.

Common Medications for Severe Acute Respiratory Syndrome

Since no specific antiviral medication is approved for treating SARS, treatment primarily involves supportive care and the use of medications to manage symptoms and prevent complications. Common medications used in the management of SARS include:

Acetaminophen (Tylenol)
- Used to reduce fever and alleviate muscle aches, headaches, and discomfort associated with SARS.
- Suitable for patients of all ages.
Ibuprofen (Advil, Motrin)
- Another option for reducing fever and managing pain, although some concerns have been raised about the use of ibuprofen in viral infections.
Antibiotics (For Secondary Bacterial Infections)
- While antibiotics are ineffective against the SARS virus itself, they may be prescribed to treat secondary bacterial infections, such as pneumonia.
Corticosteroids (e.g., Dexamethasone, Methylprednisolone)
- Used to reduce lung inflammation in patients with severe pneumonia or ARDS.
- The use of corticosteroids remains controversial due to potential side effects.
Vasopressors (e.g., Norepinephrine, Dopamine)
- Used to stabilize blood pressure in patients experiencing shock or severe hypotension.
Mechanical Ventilation
- While not a medication, mechanical ventilation is a critical treatment tool for patients with severe respiratory failure due to ARDS.

Where is Severe Acute Respiratory Syndrome Most Prevalent?

The SARS outbreak of 2002-2003 primarily affected areas in Asia, but cases were reported across multiple continents. The virus spread through international travel and infected people in healthcare settings, densely populated areas, and other high-risk environments.

Geographic Distribution of SARS During the 2002-2003 Outbreak

1. China

SARS first emerged in the Guangdong province of southern China in late 2002. The virus is believed to have originated in bats and was transmitted to humans through civet cats sold in live animal markets. China saw the highest number of SARS cases during the outbreak.

2. Hong Kong

Hong Kong was one of the epicenters of the SARS outbreak, with rapid transmission of the virus in hospitals, hotels, and apartment complexes. Crowded living conditions and dense urban populations facilitated the spread of the virus.

3. Canada

Toronto, Canada, experienced a significant outbreak of SARS due to international travelers returning from affected regions in Asia. The virus spread rapidly in hospitals, and Toronto reported one of the highest death tolls outside of Asia.

4. Southeast Asia

Countries in Southeast Asia, including Vietnam, Singapore, and Taiwan, were also significantly affected by the SARS outbreak. Healthcare workers and close contacts of infected individuals accounted for many of the cases in these regions.

5. United States

While the United States reported a few cases of SARS, the outbreak was relatively contained, with fewer deaths compared to other regions.

Risk Factors for Geographic Spread

SARS is most prevalent in areas with close contact between humans and animals, particularly in regions with live animal markets. Urban environments with dense populations are also at higher risk for rapid transmission, as seen in the 2002-2003 outbreak.

Prevention of Severe Acute Respiratory Syndrome

Preventing SARS relies on a combination of public health measures, personal hygiene practices, and infection control protocols, especially in healthcare settings. During outbreaks, timely intervention is crucial to limit the spread of the virus.

Preventive Measures

1. Isolation and Quarantine

Isolation of confirmed SARS patients and quarantine of exposed individuals are essential to prevent the spread of the virus. During the 2002-2003 outbreak, quarantine measures were implemented in many countries to limit transmission.

2. Hand Hygiene

Frequent handwashing with soap and water or using alcohol-based hand sanitizers is one of the most effective ways to prevent the spread of SARS. Hands should be washed after coughing, sneezing, or coming into contact with potentially contaminated surfaces.

3. Wearing Personal Protective Equipment (PPE)

Healthcare workers and caregivers should wear appropriate PPE, including gloves, masks, gowns, and face shields, when caring for SARS patients. This helps prevent direct contact with respiratory secretions and reduces the risk of transmission.

4. Environmental Cleaning and Disinfection

Regular cleaning and disinfection of high-touch surfaces, such as doorknobs, phones, and countertops, are important to prevent the virus from spreading via contaminated surfaces. Disinfectants that are effective against coronaviruses should be used.

5. Travel Restrictions

During the SARS outbreak, international travel restrictions were imposed to prevent the virus from spreading across borders. Screening travelers for symptoms and providing health advisories are important measures during outbreaks.

6. Avoiding Close Contact

Individuals should avoid close contact with people who are sick or exhibiting symptoms of respiratory illness. Maintaining social distancing and wearing masks in public settings can help limit the spread of SARS and other respiratory viruses.

Vaccine Development and Research

Although no specific vaccine for SARS was developed before the outbreak ended, significant research efforts were directed at creating a SARS-CoV vaccine. The knowledge gained from SARS vaccine research has informed the development of vaccines for other coronaviruses, such as the COVID-19 vaccines. Continued research into coronavirus vaccines could help prevent future outbreaks of SARS-like illnesses.