What Is Respiratory Syncytial Virus (RSV)?

Respiratory Syncytial Virus

If you’ve been around babies before or have friends with babies, then you may have heard of RSV. That’s stands for Respiratory Syncytial Virus. Many parents hear horror stories about RSV, but the reality is that for most children, it is usually a benign illness.

What Are The Symptoms of RSV?

RSV is a common respiratory virus that causes a cold-like illness: runny nose, cough, fever, sneezing. For most school-age children and adults, that’s all it does.

But for smaller children, RSV causes an illness called bronchiolitis. This is NOT bronchitis, which is more of an adult or teen illness. Bronchiolitis is an infection that causes inflammation of the small airways, causing wheezing or trouble breathing. The younger the child, the more serious the disease can be, and babies younger than 6 months are most at risk for hospitalization with RSV. Other viruses can also cause bronchiolitis, but RSV is the one that usually causes the most severe cases.

RSV can also cause pneumonia in young children, which can lead to the same symptoms.

How Common is RSV?

RSV is the most common cause of bronchiolitis and pneumonia in infants and children, accounting for more than 60% of acute respiratory infections in children around the world. In the US, RSV is responsible for 125,000 hospitalizations, and 250 infant deaths each year. RSV is almost a right of passage: nearly all children are infected at least once by the time they are 2 years old.

What Happens in Bronchiolitis?

RSV causes a strong inflammatory response, so that the child’s small airways deep in the lung are affected in three different ways:

  1. The lining of the airways are swollen from edema. That is, they are filled with extra fluid, similar to a pregnant woman’s ankles. This swelling makes the airways smaller.
  2. The virus induces a lot of mucus to be formed, which clogs up the airways and can plug up some small airways completely.
  3. In some patients, the virus can cause the muscles surrounding the airways to constrict, making them even smaller.

With all these changes, it becomes hard for the infants to breathe and they have a nearly constant cough.

How Does My Baby Catch RSV? 

Anyone can get infected with RSV if they get droplets in their mouth, nose, or eyes from a cough or sneeze by someone with RSV. They can also catch it by touching a surface with RSV on it, like a doorknob, and then touching their mouth, nose, or eyes.

The virus can live on hard surfaces (like crib railings) for 6 hours, on rubber gloves for 90 minutes, and on skin for 20 minutes.

A person usually develops symptoms about 2-8 days after coming into contact with the virus. On average, an otherwise healthy person is contagious for about 8 days, but can be contagious for as long as 3 weeks. Those with suppressed immune systems (people with cancer or HIV, for example) can shed the virus for months, even if they don’t have symptoms anymore.

In the US, there is a seasonal dimension to RSV: it wanes in the late spring and summer, and is most prevalent in the fall and winter. In addition, once you get RSV, you do NOT get lifelong immunity to it, so it is possible to get RSV bronchiolitis more than once, even more than once in a given season.

How Do We Treat RSV?

Fortunately, most children who get RSV have a mild illness that resolves on its own after 1-2 weeks. For some, hospitalization is necessary because they are feeding poorly, are dehydrated, or having difficulty breathing.

There is no medicine that will get rid of RSV, as is true of most viruses. However, there are treatments that can be given to help the baby until the infection is gone. These include:

  • Suctioning: most infants with RSV produce a lot of mucus, and getting this mucus out is the mainstay of treatment, even in the hospital. As inpatients, babies have their nose and airways suctioned out frequently by the nursing staff. At home, parents can use similar devices to keep the nose and mouth clear.
  • Oxygen: a pulse oximeter, or pulse ox, is a device that clips painlessly onto a baby’s finger or toe and can measure the amount of oxygen in the blood. If it is too low, the baby will need to admitted to the hospital for supplemental oxygen.
  • Albuterol: for some patients, using albuterol, a common asthma medicine that helps to relax the muscles around the airways and open them up, can be effective. But for most infants with RSV bronchiolitis, albuterol is ineffective. So some doctors and hospitals try to use albuterol at first, and if there is improvement, will continue to administer it. But for most babies with RSV, albuterol is not effective.
  • Supportive care: for many babies with RSV bronchiolitis, eating is difficult, and can even be dangerous, for infants are at increased risk of aspirating food when they are having trouble breathing. So maintaining adequate hydration and nutrition is important, whether at home or in the hospital.

Note that treatment does not include antibiotics or steroids. Some infants with RSV bronchiolitis will have a concurrent bacterial infection, such as an ear infection or bacterial pneumonia, and in these cases, antibiotics may be used to treat those other infections. But no antibiotics will treat the RSV.

Likewise, because infants with bronchiolitis wheeze, some have argued that steroids such as prednisone, which is used effectively for asthma patients, should be used in bronchiolitis. But multiple studies have shown that steroids are not helpful.

Who Is Most At Risk?

Anyone can get RSV, but for most children and adults, it is a mild illness. Those most at risk of having a serious case of RSV include:

  • Any baby who was premature
  • Infants 6 months or younger
  • Children younger than 2 years old with chronic lung or heart disease
  • Children who are immunocompromised (have weaker immune systems)
  • Children with neuromuscular disorders who have difficulty swallowing or clearing their secretions

Palivizumab (Synagis®) is a preventive treatment for RSV. It is made in lab and consists of a shot of antibodies against RSV that helps to protect the child. Almost all the other shots children receive rely on active immunization, but palivizumab is a passive immunization. That is, the shot does not induce the child’s immune system to produce antibodies against RSV (which then provides lifelong immunity). The shot gives the antibodies to the child, temporarily protecting her, but the child needs the shot frequently: once a month for 5 months over the late fall and winter months. Currently, at $3000 a vial, this is a very expensive prevention, and meant for only the following select patients:

  • Infants who are 6 months of age or younger at the beginning of RSV who were born at 29 weeks gestation or earlier
  • Infants who are 24 months of age or younger at the beginning of RSV season with bronchopulmonary dysplasia (BPD)
  • Infants who are 24 months of age or younger at the beginning of RSV season with hemodynamically significant congenital heart disease.

But even with palivizumab, infants can get RSV bronchiolitis. However, several RSV vaccines are being tested currently.

So How Can I Prevent My Healthy Baby From Getting RSV?

There is no guaranteed way to prevent an RSV infection. But the following are some ways to help keep your baby healthy:

  • Frequent hand washing for 20 seconds with soap and water or alcohol-based rubs
  • Avoid close contact (kissing, sharing cups, etc.) with sick people
  • Cough or sneeze into a tissue or the sleeve of your upper arm
  • Avoid touching your eyes, nose, and mouth with your hands
  • Clean and disinfect surfaces in your home

The other key is to call your doctor if your child’s cough seems more frequent, she has a lot of mucus from her nose, has difficulty eating, or can’t sleep due to the cough. Also, call if your child has any signs of trouble breathing, such as breathing rapidly, or labored breathing (ribs appear to be poking out with each breath, the notch above the breast bone is sinking in with each breath, the nostrils are flaring with each breath, or the abdomen is see-sawing deeply with each breath). This is especially true if your child is one of those at high risk.

Ruben Rucoba
Dr. Rucoba has over 25 years of experience as a primary care pediatrician after completing medical school at the University of California, San Francisco. His clinical areas of expertise include caring for children with special health care needs and assisting families with international adoption. He has been a freelance medical writer since 2010, writing for health websites, continuing medical education providers, and various print outlets. He currently works at Wheaton Pediatrics in the suburbs of Chicago, where he lives with his wife and four daughters, including a set of twins.

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