Respiratory Syncytial Virus (RSV)
Respiratory syncytial virus (RSV) is a common cause of fall, winter, and spring outbreaks of acute respiratory disease in young children and adults. Hawaii and Florida experience RSV infections year-round. RSV was originally called the chimpanzee corzya virus because it was first isolated from a chimpanzee with rhinorrhea. Its name was changed to RSV when scientists discovered that it caused infected epithelial cells to fuse together and form giant cells known as syncytia.
RSV season generally begins in November and continues for a mean of 22 weeks, through April. RSV is primarily transmitted by large airborne droplets that come in contact with the eyes and nose. Some cases may be spread by touching contaminated surfaces. RSV is the most common cause of bronchiolitis and pneumonia in young children and is the number one cause of hospitalizations in children under the age of 1 in the United States. Children of any age with underlying cardiac or pulmonary disease or who are immunocompromised are at risk for serious complications from this virus. Because natural infection with RSV provides limited protective immunity, RSV causes repeated symptomatic infections throughout life.
In adults, RSV usually causes upper respiratory tract manifestations but may cause lower respiratory tract disease, especially in the elderly and in immunocompromised persons. Most patients recover in one to two weeks, but infection in immunocompromised persons can be associated with high death rates. RSV kills more adults in the United States than children. According to the CDC, RSV kills 14,000 adults and 100 to 500 children each year.
RSV is a common, but preventable, cause of nosocomial infection, especially during community outbreaks. Sources for nosocomial infection include infected patients, staff, visitors, or contaminated surfaces.
Ribavirin therapy may be considered for patients who are seriously ill or who are at high risk for severe complications of the infection. RSV immune globulin was licensed for use in January 1996. Monoclonal antibodies, palivizumab and nirsevimab, can be used to prevent disease. Glaxo Smith Kline and Pfizer are developing RSV vaccines.
RSV can be detected by viral culture, rapid antigen testing, or multiplex respiratory pathogen panels. Cultures require 3 to 14 days’ incubation before cytopathic effects are seen. The sensitivity of cultures is often impaired by the lability of the virus during specimen transport to the laboratory. Rapid antigen testing for RSV overcomes this limitation and is much quicker to perform. Comparisons with culture have shown the rapid antigen test to be very sensitive and specific. RSV antigen results are reported as negative or positive. Reference value is a negative result.
Adequate specimen collection is crucial to achieve accurate test results. A nasopharyngeal aspirate should be obtained. Nasal swabs are not adequate for RSV testing and may cause false negative results. An equivocal or negative test does not eliminate the possibility of RSV infection, because inadequate collection, improper handling, or low-level virus shedding may cause them.
