Respiratory Syncytial Virus (RSV) is a widespread respiratory virus that infects the nose, throat, and lungs, commonly causing mild, cold-like symptoms. However, it can lead to severe lung infections, particularly in vulnerable populations. Understanding the predictable seasonal patterns of RSV activity, including periods of increased cases, is important for public health.
When RSV Season Peaks
The “peak” of RSV refers to the period when the incidence of cases is highest. In the Northern Hemisphere, RSV activity typically increases during late fall, continues through winter, and subsides in early spring. The peak season generally occurs from mid-December to early February.
The exact timing and duration of the RSV season can vary by geographic location, year to year, and even within different regions of a country. For instance, southern states in the United States may experience earlier RSV seasons compared to northern regions. Health agencies like the Centers for Disease Control and Prevention (CDC) monitor RSV activity through various surveillance systems to identify when the peak is occurring or has passed. These systems collect data on laboratory-confirmed cases and hospitalizations to track seasonal trends and circulation patterns.
Why RSV Cases Surge Seasonally
Several factors contribute to the seasonal surge and peak of RSV cases. Environmental factors play a role, with colder temperatures and lower humidity potentially aiding viral survival and transmission.
Behavioral factors also influence the seasonal surge. Increased indoor gatherings during colder months, as well as the reopening of schools, lead to closer contact among individuals, facilitating the spread of the virus. RSV spreads efficiently through respiratory droplets from coughing and sneezing, as well as by touching contaminated surfaces and then one’s eyes, nose, or mouth.
Navigating the Peak for High-Risk Individuals
The RSV peak carries implications for those most vulnerable to severe illness. High-risk groups include infants, especially premature babies and those under six months of age, older adults, and individuals with compromised immune systems or chronic lung or heart conditions.
These groups are particularly susceptible to severe outcomes such as bronchiolitis, an inflammation of the small airways in the lungs, and pneumonia, a lung infection. RSV is the most common cause of bronchiolitis and pneumonia in children younger than one year of age. In severe cases, individuals may require additional oxygen, rehydration, or even mechanical ventilation.
To navigate the peak season, high-risk individuals and their caregivers should practice preventative measures. Frequent handwashing is advised, along with avoiding close contact with sick individuals. Cleaning and disinfecting frequently touched surfaces, like doorknobs and toys, can also help reduce transmission.
Consulting healthcare providers about available preventative measures is also recommended. Vaccines are available for adults 60 years and older, and for pregnant women between weeks 32 and 36 of pregnancy to protect their newborns. A monoclonal antibody product is available for eligible infants and some young children, including premature babies or those with certain medical conditions, to provide passive immunity and help prevent severe illness.