RSV or Respiratory Syncytial Virus infection is a common respiratory infection that primarily affects infants and young children, although people of all ages can catch it. Young infants and senior adults are at most risk. The infection is characterized by fever, runny nose, cough, poor appetite and occasionally lower airway involvement that causes wheezing. When RSV infection causes wheezing the condition is called bronchiolitis. 

Thankfully, most RSV infections are not serious and will resolve without incident in about two weeks. Because RSV infections do not cause life long immunity, it is possible to be re-infected with RSV many times. RSV is spread through aerosolized droplet or by fomite (infected objects the ill person has handled, such as toys). The infection is very contagious and affects both children and adults. Very young children less than 12 months old and children with medical problems are at a higher risk of a more serious RSV infection or complications of RSV. RSV typically occurs during the winter months and spreads through respiratory droplets from coughs or sneezes. A vaccine for pregnant women and a monoclonal antibody injection are available to prevent severe RSV infection in babies. See our immunization section of this handbook page 158.

Symptoms of Bronchiolitis

Most children infected with RSV will have only cold symptoms (runny nose, cough, poor appetite and fever). Besides the runny nose, RSV infection in some children can go down into the chest and cause the bronchioles to become swollen, constricted, and filled with thick mucous. These factors cause the lungs to develop obstruction to the flow of air. This obstruction causes the hallmark symptom of bronchiolitis: wheezing. Wheezing refers to the high pitched, or whistling sound that air makes when being forcibly pushed through swollen, constricted air passages. Approximately 20% of children who catch RSV will develop wheezing.

In addition to wheezing, the swollen, constricted, mucous filled bronchioles cause a severe, wet sounding cough as the child tries to clear the thick mucous from the airways. Coughing is an important defense mechanism of the body in bronchiolitis which should not be interfered with because it protects against the development of bacterial pneumonia.

Another worrisome symptom of bronchiolitis is rapid breathing. Respiratory rates greater than 60 breaths per 60 seconds are worrisome. This may indicate that the child is having difficulty getting enough air in and out of the lungs to meet the oxygen demands of the body. Often this type of respiratory distress is accompanied by retractions, which refers to sinking in of the skin between the ribs, near the collar bone and at the base of the neck which occurs with breathing. 

Usual Course of Bronchiolitis

After an incubation period of 4 to 7 days, the first symptom of RSV is a runny nose. This may be associated with a fever. A cough then develops one to two days later. This can be followed by wheezing and sometimes shortness of breath. Very young infants less than 6 months old who catch RSV are more prone to severe disease. Rarely apnea (stopping breathing) can happen in young infants with the infection.

Early signs of RSV bronchiolitis may appear like a cold, but they can progress and result in more severe symptoms. Early symptoms often include:

• Coughing
• Sneezing
• Runny or stuffy nose
• Mild sore throat
• Mild to moderate fever (101-102.9 degrees F)

More concerning later symptoms are:

• Wheezing or difficulty breathing
• Rapid breathing
• Flaring of nostrils
• Retractions (visible pulling in of the muscles between the ribs or above the sternum)
• Poor feeding
• Irritability or decreased activity levels

Contact us within 24 hours if your child:

1. Poor drinking or eating or begins to show early signs of dehydration (dry mouth, no tears, reduced urine output).
2. Develops an earache.
3. Develops difficulty sleeping, but is OK otherwise.

More severe breathing problems are more worrisome. You should contact us immediately if these symptoms develop in your child:

1. labored or difficult breathing.
2. rapid breathing faster than 60 breaths per 60 seconds while your child is resting.
3. significant retractions (sinking in of the skin between the ribs, near the collar bone and at the base of the neck which occurs with breathing)
4. wheezing worsens.
5. stops breathing or passes out.
6. appears to be sicker and not doing well.
7. a blue color of the lips and the area around the lips.
8. Lethargy or extreme fatigue.
9. Fever (rectal temperature over 100.4°F or 38°C) in infants younger than 2 months.

Your child is contagious for two weeks from the beginning of the ill- ness. Most children will have resolution of symptoms within two weeks of onset of the illness. Symptomatic treatment is all that is required.

Treatment:

The treatment of RSV for most children will be same as a common cold. Treatment consists of hydration, nasal saline and suction, humidifier and fever reduction as needed. Children who have mild wheezing should be seen in the office for an appointment during regular office hours. Your child’s respiratory status will be assessed. Rarely, some children with RSV infection can develop more severer respiratory difficulty. They may require further intervention and sometimes hospitalization.

Supportive Care: Most cases of RSV bronchiolitis only require supportive care at home, including:

• Providing plenty of fluids to prevent dehydration.
• Using a cool mist humidifier or saline nasal drops to ease congestion.
• Offering smaller, more frequent meals to prevent fatigue during feeding.
• Use acetaminophen or ibuprofen to control fever or discomfort (do not use aspirin).

Hospitalization: Severe cases, especially in young infants or those with certain risk factors, may require hospitalization. In the hospital, treatment generally involves close monitoring, supplemental oxygen, and, in severe cases, assisted breathing with a mechanical ventilator.

Prevention:

Preventing the spread of RSV is crucial, especially for vulnerable populations. Here are some preventive measures:

• Frequent Hand Hygiene: Wash hands thoroughly with soap and water, particularly before touching the baby or any surfaces they come in contact with.
• Limit Exposure: Avoid close contact with individuals who have respiratory symptoms, such as coughing or sneezing. It is especially important to limit contact with infants and those with weakened immune systems during the RSV season.
• Maintain a Clean Environment: Clean and disinfect frequently touched objects and surfaces, such as toys, doorknobs, and counter-tops.
• Promote Good Health Practices: Encourage individuals to cover their mouth and nose with a tissue or their elbow when coughing or sneezing. Encourage getting vaccinated against other respiratory illnesses, such as influenza.
• In pregnant women, Abrysvo is available. See our immunization section.
• For babies less than 8 months of age during RSV season, a monoclonal antibody against RSV called Beyfortus is available. See our immunization section.

RSV bronchiolitis is a common respiratory infection in infants and young children. By recognizing the common symptoms, understanding treatment options, and focusing on preventive measures, you can help pro- tect your child and minimize the impact of RSV bronchiolitis.