Respiratory Viruses

Respiratory syncytial virus (RSV) was discovered in 1956 and has since been recognized as one of the most common causes of childhood illness. It causes annual outbreaks of respiratory illnesses in all age groups. In most regions of the United States, RSV usually circulates during fall, winter, and spring, but the timing and severity of RSV season in a given community can vary from year to year.

RSV infection can cause a variety of respiratory illnesses in infants and young children. It most commonly causes a cold-like illness but can also cause lower respiratory infections like bronchiolitis and pneumonia. One to two percent of children younger than 6 months of age with RSV infection may need to be hospitalized. Severe disease most commonly occurs in very young infants. Additionally, children with any of the following underlying conditions are considered at high risk:

• Premature infants
• Very young infants, especially those 6 months and younger
• Children younger than 2 years old with chronic lung disease or congenital heart disease
• Children with suppressed immune systems
• Children who have neuromuscular disorders, including those who have difficulty swallowing or clearing mucus secretions

Infants and young children with RSV infection may have rhinorrhea and a decrease in appetite before any other symptoms appear. Cough usually develops one to three days later. Soon after the cough develops, sneezing, fever, and wheezing may occur. In very young infants, irritability, decreased activity, and/or apnea may be the only symptoms of infection.

Most otherwise healthy infants and young children who are infected with RSV do not need hospitalization. Those who are hospitalized may require oxygen, intubation, and/or mechanical ventilation. Most improve with supportive care and are discharged in a few days.

Adults who get infected with RSV usually have mild or no symptoms. Symptoms are usually consistent with an upper respiratory tract infection which can include rhinorrhea, pharyngitis, cough, headache, fatigue, and fever. Disease usually lasts less than five days.

Some adults, however, may have more severe symptoms consistent with a lower respiratory tract infection, such as pneumonia. Those at high risk for severe illness from RSV include

• Older adults, especially those 65 years and older
• Adults with chronic lung or heart disease
• Adults with weakened immune systems

RSV can sometimes also lead to exacerbation of serious conditions such as

• Asthma
• Chronic obstructive pulmonary disease (COPD)
• Congestive heart failure