This year, emergency departments nationwide are seeing an unusually early surge in very young and elderly patients with respiratory distress, often caused by respiratory syncytial virus or RSV. We asked UCSF Benioff Children's Hospital experts Steven Bin, MD, medical director of Pediatric Emergency Medicine; Ann Petru, MD, director of Infectious Diseases; Ted Ruel, MD, chief of Pediatric Infectious Diseases and Global Health; Christopher Vlasses, MD, associate professor of pediatrics; and April Zaat, MD, associate director of hospital medicine, to weigh in on what RSV is and why we're seeing so many cases.
What is RSV?
Respiratory syncytial virus is a seasonal respiratory virus that usually causes mild, cold-like symptoms. Most people recover in a week or two, but RSV can be serious, especially for infants and older adults.
Why are we seeing more RSV cases earlier this year?
The spread of RSV began in mid-October this year, which was earlier than usual. We usually see RSV patients from December through February. This is likely because COVID precautions like masking and shelter-in-place mandates were lifted this summer and, as the weather chilled, socializing indoors accelerated an earlier and more rapid spread of the virus.
We are also seeing older babies with RSV than in previous years. In pre-pandemic times, most babies contracted RSV by the time they were 2 years old, according to the CDC. But we are seeing an unusual influx of RSV patients ages 2-4 year this year, likely because these toddlers and young children were not exposed to the virus as newborns when most people were wearing masks and when schools were closed, so many have not developed protective antibodies.
What are the symptoms of RSV?
People infected with RSV usually show symptoms similar to a common cold within four to six days after becoming infected. Symptoms include:
- Runny nose
- Decrease in appetite
- Coughing
- Sneezing
- Fever
- Wheezing
- Lethargy
- Trouble breathing
Who is most vulnerable to RSV?
Those most susceptible to RSV are premature infants, newborns and babies - especially those younger than 6 months - children younger than 2 years old with chronic lung disease or congenital heart disease, and children with weakened immune systems.
Similarly, older children and adults with chronic heart, lung or immunity problems can also be severely impacted by RSV.
