Respiratory Syncytial Virus (RSV). Causes and Treatment

The leading cause of lower respiratory tract infections in infants and young children is respiratory syncytial virus (RSV). RSV is responsible for millions of children under the age of five years suffering this illness in the United States, causing more than 125,000 children to be hospitalized. RSV also affects those over sixty-five, causing 177,000 hospitalizations and 14,000 deaths each year.

Adults of any age can get it too, but the illness is often not as severe. The overall treatment recommendations are supportive care. It is no surprise that the World Health Organization (WHO) has a goal to support vaccine development for this virus.

Infants and young children

The infection usually causes bronchiolitis or viral pneumonia. Bronchiolitis is an acute inflammatory injury of the bronchioles, or small pathways in the lungs. Bronchiolitis can occur at any age, but young children and infants are affected more as their airways are smaller.

Infants and younger children present with the following symptoms with an RSV infection:

  • Cough.
  • Tachypnea (rapid heart rate).
  • Cyanosis (turning blue).
  • Chest retractions.
  • Wheezing.
  • Rales (crackling or high-pitched sounds in their lungs when they breathe).

During a physical examination, commonly, children can also have the following:

  • Diffuse small airway disease.
  • Otitis media (ear infections).
  • Dehydration (their skin and mucous membranes appear dry).

Once diagnosed, the child can be isolated and the parents, family, friends and the hospital or clinic staff may be educated on the symptoms and treatment of RSV.

Doctors may order the following tests:

  • Complete blood count.
  • Serum electrolyte concentrations.
  • Urinalysis.
  • Oxygen saturations.
  • Chest X-ray (the findings usually are neither specific to RSV nor are they predictive of the clinical course).
  • Newer specific diagnostic tests are now available for confirmation of RSV including:
    • Culture (human epithelial type-2 or Hep-2).
    • Antigen-revealing techniques with a rapid turnaround of 30 minutes.
    • Molecular probes such as multiplex PCR assays.

Management of a child with RSV remains largely supportive, including supplemental oxygen when needed, managing the respiratory symptoms and secretions, and maintaining hydration.

The American Academy of Pediatrics in 2014 published Clinical Practice Guidelines that did not recommend many commonly used medications such as bronchodilators, epinephrine, and corticosteroids. However, in clinical experience, many medications are helpful in at least a subset of these patients, including bronchodilators. Some doctors will use alpha agonists or drugs called sympathomimetics for short-term benefit for children with acute bronchiolitis episodes.

Ribivarin, also known as tribavirin, is an antiviral medication used for treating RSV and other illnesses such as hepatitis C, and can be used in selective circumstances. Ribivarin is typically used when there are significant underlying risk factors and severe RSV disease such as with transplant recipients, but even then, the clinical benefits are unpredictable and uncertain.

In addition to the ongoing search for a vaccine, the American Academy of Pediatrics has some preventative recommendations, which include:

  • Vitamin D supplementation including supplementation during pregnancy.
  • Breast feeding may also provide some protection against severe RSV disease.

What leads to increased risk for RSV infections?

A number of factors have been associated with an increased risk of acquiring RSV disease. These are important considerations in the community setting for all families. They include:

  • Attending daycare.
  • Older siblings in preschool or school.
  • Crowding and lower socioeconomic status.
  • Exposure to environmental pollutants (eg. cigarette smoke).
  • Multiple birth sets (especially triplets or greater).
  • Minimal breastfeeding.

What has been associated with more severe disease or the need for hospitalization?

  • Prematurity. Even though the greatest risk for severe disease is in premature infants born at less than 29-week gestation, recent data continues to demonstrate increased risk up to 35 weeks gestation.
  • Age younger than three months at the time of infection.
  • Chronic lung disease.
  • Congenital heart disease.
  • Congenital immunodeficiency.
  • Severe neuromuscular disease.
  • Toxic appearance at time of presentation.
  • Respiratory rate higher than seventy breaths per minute on room air.
  • Atelectasis or pneumonitis on chest X-rays (evidence of lung collapse).
  • Oxygen saturation lower than 95% in room air.

When do RSV infections occur?

Most RSV infections occur during the winter months. The exception is Florida where the incidence of RSV infections may extend to the entire year. In tropical climates, peak RSV infections occur during the rainy seasons.

Older children with immunocompromised systems or elderly people with chronic obstructive pulmonary disorder, or those over 65 years are subject to RSV more than younger adults.

What is the prognosis after being diagnosed with RSV?

The good news is that most children recover well, even those who are admitted to the hospital. The recovery usually takes about a week. High-risk infants may require longer.

Death from RSV remains less than one percent, and in the United States, there are fewer than five hundred deaths each year at any age.

Re-infection can occur throughout life, but typically the infection is limited to the upper respiratory tract with advancing age. There are no increased incidences of RSV infection with males or females or any particular group of people.

Key take-aways

Most children and adults who have RSV will recover with supportive care. Most children do well at home as an outpatient as they recover, particularly if they can take fluids by mouth and breathe well on room air.

Even though many doctors will prescribe bronchodilators, there is no convincing evidence that this helps. Rarely, children are placed on mechanical ventilation. IV fluids are generally administered for a brief course. Steroids are used in many hospital settings, but overall clinical data do not support their use.

If Ribivarin is considered, an infectious disease specialist consultation is warranted. A pediatric pulmonologist is needed if the child or infant has underlying lung disease such as bronchopulmonary dysplasia if the infant is premature.

Adults with RSV also recover well in most instances unless they have other underlying lung problems or are immunocompromised.

At any age, a good tip toward prevention of RSV is Vitamin D supplementation, particularly during pregnancy. In a prospective clinical study, neonates born with low Vitamin D concentrations in their blood had a six-fold greater risk of RSV infection in the first year of life.1 This finding indicates it may be good preventative care to discuss with your doctor about supplementing Vitamin D during pregnancy.

References:

Mayo Clinic. Respiratory Syncytial virus.

Yale Medicine. RSV Respiratory Syncytial Virus.

Centers for Disease Control and Prevention. RSV Symptoms.

Belderbos, M.E., Houben, M.L., Wilbrink, B., et al. (June 2011). Cord blood vitamin d deficiency is associated with respiratory syncytial virus bronchiolitis. Pediatrics.

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