Respiratory Syncytial Virus

Key Features

• Bronchiolitis, proliferation and necrosis of bronchiolar epithelium develop, producing obstruction from sloughed epithelium and increased mucus secretion

• Apnea, low-grade fever, tachypnea, and wheezes

• Hyperinflated lungs, decreased gas exchange, and increased work of breathing

• Prematurity is a major risk factor for severe disease

Clinical Findings

• Annual epidemics occur in winter and spring

• Average incubation period is 5 days

• Inoculation may occur through the nose or the eyes

• In children

  • Most common cause of acute lower respiratory infection

  • Common cause of acute and recurrent otitis media

• In adults

  • Causes upper and lower respiratory tract infection with increasingly recognized severity in

    • Persons with comorbid conditions

    • Elderly persons

    • Persons with severe combined immunodeficiency

    • Persons who have undergone lung or bone marrow transplantation

  • Recurrent infections occur throughout life

• In immunocompromised patients, such as bone marrow transplant recipients, serious pneumonia can occur

Diagnosis

• Polymerase chain reaction (PCR) is used

• Rapid diagnosis possible by viral antigen identification in nasal washings using an ELISA or immunofluorescent assay

• Multiplex assays in conjunction with influenza A and B tests are available commercially

• RSV viral load assay values at day 3 of infection correlate with requirement of intensive care and respiratory failure

Treatment

• Hydration, humidification of inspired air, antibiotic therapy, and ventilatory support as needed

• In non–high-risk populations, ribavirin, bronchodilators, and corticosteroids are widely used, but evidence for their effectiveness is lacking

  • Ribavirin contraindicated in pregnancy

• Palivizumab

  • Prophylactic monoclonal antibody

  • Effective in high-risk infants (congenital heart and lung diseases, Down syndrome)

  • Significantly lowers incidence of recurrent wheezing

  • Not proven effective among adults with RSV

• Azithromycin therapy has been shown to reduce the probability of recurrent wheezing during the subsequent year by approximately 50%