Respiratory syncytial virus

Definition

Respiratory syncytial virus (RSV) is a virus that causes infections of the lungs and respiratory tract. It's so common that most children have been infected with the virus by age 2. Respiratory syncytial virus can also infect adults.

In adults and older, healthy children, the symptoms of respiratory syncytial virus are mild and typically mimic the common cold. Self-care measures are usually all that's needed to relieve any discomfort.

Infection with respiratory syncytial virus can be severe in some cases, especially in premature babies and infants with underlying health conditions. RSV can also become serious in older adults and adults with heart and lung diseases.

Common-sense precautions can help prevent the spread of respiratory syncytial virus.

Symptoms

Signs and symptoms of respiratory syncytial virus infection typically appear about four to six days after exposure to the virus. In adults and children older than 3, RSV usually causes mild cold-like signs and symptoms. These include:

• Congested or runny nose
• Dry cough
• Low-grade fever
• Sore throat
• Mild headache
• A general feeling of unease and discomfort (malaise)

In children younger than 3 years of age, respiratory syncytial virus can lead to a lower respiratory tract illness such as pneumonia or bronchiolitis — an inflammation of the small air passages entering the lungs. Signs and symptoms may include:

• High fever
• Severe cough
• Wheezing — a high-pitched noise that's usually heard on breathing out (exhaling)
• Rapid breathing or difficulty breathing, which may make the child prefer to sit up rather than lie down
• Bluish color of the skin due to lack of oxygen (cyanosis)

Infants are most severely affected by RSV. They may markedly draw in their chest muscles and the skin between their ribs, indicating that they are having trouble breathing, and their breathing may be short, shallow and rapid. They may cough. Or they may not show any signs of a respiratory tract infection, but will eat poorly and be unusually lethargic and irritable.

Most children and adults recover from the illness in eight to 15 days. But in young babies, infants born prematurely, or infants or adults who have chronic heart or lung problems, the virus may cause a more severe — occasionally life-threatening — infection that requires hospitalization.

Causes

Respiratory syncytial virus enters your body though your eyes, nose or mouth. It spreads easily when infectious respiratory secretions — such as those from coughing or sneezing — are inhaled or passed to others through direct contact, such as shaking hands. The virus can also live for hours on objects such as countertops and toys. Touch your mouth, nose or eyes after touching a contaminated object, and you're likely to acquire the virus.

An infected person is most contagious in the first few days after infection, but RSV may spread for up to a few weeks after the start of infection.

Risk factors

By age 2, most children will have been infected with respiratory syncytial virus. Children who attend child care centers or who have siblings who attend school are at a higher risk of exposure. So are infants who are exposed to high levels of air pollution or cigarette smoke. Susceptibility is also greater during the peak RSV season, which typically begins in the fall and ends in the spring.

People at increased risk of severe — sometimes life-threatening — infections include:

• Infants younger than 6 months of age
• Younger children, especially under 1 year of age, who were born prematurely or who have an underlying condition, such as congenital heart or lung disease
• Children with weakened immune systems, such as those undergoing chemotherapy or transplantation
• Older adults
• Adults with congestive heart failure or chronic obstructive pulmonary disease

When to seek medical advice

Most cases of respiratory syncytial virus infection aren't life-threatening. Still, seek medical advice for a child, older adult or other person at high risk who experiences any of its signs and symptoms. Also seek immediate medical attention if your child experiences difficulty breathing, runs a high fever or turns blue in color.

Tests and diagnosis

Your doctor may suspect respiratory syncytial virus based on a physical exam and the time of year of the infection. During the exam, he or she may listen to the lungs with a stethoscope to check for wheezing or other abnormal sounds.

Your doctor may also use:

• Painless skin monitoring to check whether the level of oxygen available in the bloodstream is lower than usual
• Blood tests to check white cell counts or to look for the presence of viruses, bacteria or other organisms
• Chest X-rays to check for pneumonia

In addition, your doctor may collect respiratory secretions from your nose to test for the virus in a lab.

Complications

Respiratory syncytial virus is the most common cause of respiratory illness in infants and young children. Although the infection produces only mild signs and symptoms in most people, it can be severe in babies younger than 6 months old, babies that are born prematurely, and babies with congenital heart or lung disease.

Each year, up to 125,000 infants in the United States are hospitalized with severe RSV. Still, death is uncommon.

Of infants and young children experiencing their first RSV infection, many also experience symptoms of bronchiolitis and pneumonia. Middle ear infections — which occur when microorganisms infiltrate the space behind the eardrum — are another complication. There may be a link between severe respiratory syncytial virus and the chance of developing asthma later in life.

Recurring infections
Once a person has been infected with the virus, it's common to occasionally experience a recurrence of RSV throughout life, usually in the form of a common cold. Although subsequent infections typically aren't as severe, they can be serious in older adults or people with chronic heart or lung disease.

Treatments and drugs

Antibiotics, which doctors prescribe to treat bacterial infections, are of no use against respiratory syncytial virus because it's a viral infection. However, your doctor may prescribe antibiotics if there's a bacterial complication, such as middle ear infection or bacterial pneumonia.

Otherwise, he or she may recommend an over-the-counter medication such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin, others), depending on your age. These medications reduce fever but won't cure the infection or make it go away sooner.

Treating severe cases
In cases of severe infection, hospitalization may be necessary to provide intravenous (IV) fluids and humidified oxygen. Hospitalized infants and children may also be hooked up to mechanical ventilation — a breathing machine — to ease breathing.

In some severe cases, a nebulized bronchodilator such as albuterol (Proventil, Ventolin) may be used to relieve wheezing. This medication opens air passages in the lungs. Nebulized means it's administered as a fine mist that you breathe in. Occasionally, a nebulized form of ribavirin (Rebetol), an antiviral agent, may be used. Your doctor may also recommend an injection of epinephrine or a form of epinephrine that can be inhaled through a nebulizer (racemic epinephrine) to relieve symptoms of RSV infection.

Prevention

No vaccine exists for respiratory syncytial virus. But common-sense precautions can help prevent the spread of this infection:

• Wash your hands frequently. Do so particularly before touching your baby, and teach your children the importance of hand washing.
• Avoid exposure. Limit your infant's contact with people who have fevers or colds. This is especially important in premature babies and all infants in the first 2 months of life.
• Keep things clean. Make sure countertops are clean in the kitchen and bathrooms, especially when someone in your family has a cold. Discard used tissues right away.
• Don't share drinking glasses with others. Use your own glass or disposable cups when you or someone else is sick. Label each person's cup.
• Don't smoke. Infants who are exposed to tobacco smoke have a higher risk of contracting RSV and potentially more severe symptoms. If you do smoke, never do so inside the house or car.
• Wash toys regularly. Do this especially when your child or a playmate is sick.

Protective medication
In addition, the medication palivizumab (Synagis) can help protect children under age 2 who are at high risk of serious complications when they get RSV, such as those born prematurely or with congenital heart or lung disease.

Synagis works by providing the necessary antibodies to protect against respiratory syncytial virus. It requires a monthly injection into the muscle tissue of the thigh during the peak RSV season, beginning in the fall and continuing for about five months (usually November through April). Injections are repeated every year until the child is no longer at high risk. The medication doesn't interfere with childhood vaccines.

Use of this treatment decreases the frequency and length of hospitalization for respiratory syncytial virus infections. But the high cost of the medication limits its use to those at highest risk of complications from RSV infections. The medication isn't helpful in treating respiratory syncytial virus infection once it has developed. Talk to your doctor if you think your child may qualify for this treatment.

Scientists are working to find a vaccine against the respiratory syncytial virus not only in infants but also in older adults and high-risk adults.

Lifestyle and home remedies

You may not be able to shorten the duration of a respiratory syncytial virus infection, but you can try to relieve some signs and symptoms.

If your child has the infection, do your best to comfort or distract him or her — cuddle, read a book or play a quiet game. Other tips for relieving symptoms include:

• Create moist air to breathe. Keep your room or your child's room warm but not overheated. If the air is dry, a cool-mist humidifier or vaporizer can moisten the air and help ease congestion and coughing. Be sure to keep the humidifier clean, to prevent the growth of bacteria and molds. An ideal indoor humidity is around 50 percent.
• Sit in an upright position. Sitting upright makes breathing easier. Placing your infant in a car seat may help. When sleeping, place your infant on his or her back on a firm mattress as usual, but elevate the head of the mattress about 3 inches with an object underneath the mattress.
• Drink fluids. Warm fluids, such as a favorite soup, may be soothing and help loosen thickened secretions. If your child loves ice pops, now may be the time for a special cool treat. Keep breast-feeding or bottle-feeding your infant as you would normally. Nutrition is vital.
• Try saline nasal drops. Over-the-counter (OTC) drops are a safe, effective way to ease congestion, even for young children. Drip several drops into one nostril to loosen hardened mucus, then immediately suction that nostril, using a bulb syringe. Repeat the process in the other nostril. A good time to do this is before feedings and before putting your baby down to sleep.
• Use over-the-counter pain relievers. OTC pain relievers such as acetaminophen (Tylenol, others) may help reduce fever, relieve a sore throat and improve ability to drink fluids. Check with your doctor about age-appropriate use and doses of such medications. Don't use them to suppress low-grade fevers under 100.9 F.
• Eliminate exposure to cigarette smoke. Stay away from cigarette smoke because it can aggravate symptoms.