Why do you get rsv

Overview

Respiratory Syncytial Virus (RSV) is a single-stranded RNA virus belonging to the Pneumoviridae family, first identified in 1956 when researchers isolated it from chimpanzees with respiratory illness. The virus was named for its characteristic ability to cause infected cells to fuse together, forming syncytia. RSV circulates worldwide, typically causing seasonal outbreaks during fall, winter, and spring in temperate climates. The virus has two major subtypes, A and B, which often co-circulate during outbreaks. RSV is highly contagious, spreading through respiratory droplets when an infected person coughs or sneezes, and can survive on surfaces for several hours. Historically, RSV has been recognized as the most common cause of bronchiolitis and pneumonia in children under 1 year old in the United States, with surveillance data showing consistent annual epidemics. The virus affects all age groups but causes the most severe disease in infants, older adults, and immunocompromised individuals.

How It Works

RSV infection begins when the virus enters the respiratory tract through the nose or mouth, typically via inhalation of respiratory droplets or contact with contaminated surfaces. The virus attaches to epithelial cells lining the airways using its surface glycoproteins, particularly the G protein for attachment and the F (fusion) protein for entry into host cells. Once inside, RSV replicates in the cytoplasm of infected cells, producing new viral particles that spread to neighboring cells. The F protein facilitates cell-to-cell spread by causing infected cells to fuse with adjacent uninfected cells, forming multinucleated syncytia that are characteristic of RSV infection. This cellular damage triggers an immune response involving cytokines and inflammatory cells, which can cause airway inflammation, increased mucus production, and edema. In severe cases, particularly in infants with small airways, this inflammation leads to bronchiolitis characterized by wheezing, coughing, and respiratory distress. The immune response to RSV infection provides only partial and temporary protection, allowing reinfections throughout life, though subsequent infections are generally milder.

Why It Matters

RSV represents a significant public health burden globally, particularly for vulnerable populations. In infants, RSV is the leading cause of hospitalization for respiratory illness, accounting for approximately 20% of all pediatric hospitalizations for pneumonia worldwide. Beyond the immediate health impact, severe RSV infection in infancy has been associated with increased risk of developing asthma and recurrent wheezing later in childhood. For older adults, RSV causes substantial morbidity and mortality, with estimates suggesting it may be responsible for up to 14,000 deaths annually in Americans 65 and older. The economic burden is considerable, with direct medical costs for RSV hospitalizations in the U.S. exceeding $1 billion annually. Recent advances in prevention, including monoclonal antibody treatments for infants and vaccines for older adults, highlight the growing recognition of RSV's importance and offer promising tools to reduce its impact on healthcare systems and vulnerable populations.