What causes rsv in adults

What It Is

Respiratory Syncytial Virus (RSV) is a common, highly contagious respiratory virus that causes infections of the lungs and airways. In adults, RSV infection manifests as lower respiratory tract disease, potentially progressing to severe pneumonia or bronchiolitis. The virus is a single-stranded, negative-sense RNA virus belonging to the Pneumoviridae family, first identified in 1956. RSV affects the epithelial cells lining the respiratory tract, causing inflammation and mucus production that characterizes the illness.

Historically, RSV was identified in chimpanzees in 1956 and subsequently discovered in human patients suffering from lower respiratory tract infections. The virus gained significant medical attention in the 1960s when researchers discovered it caused serious complications in infants with congenital heart disease. Throughout the 1980s and 1990s, epidemiological studies established RSV as a major cause of winter respiratory illness. In 2023, the FDA approved the first RSV vaccine (Arexvy) for adults 60 and older, marking a significant milestone in adult RSV prevention.

RSV exists in two major antigenic groups: Group A and Group B, with numerous subgroups identified through molecular analysis. Genetic variations among RSV strains result in different virulence levels and immune responses in infected individuals. Both groups circulate simultaneously but show variations in prevalence year to year. These molecular differences affect clinical severity, vaccine effectiveness, and immune evasion capabilities of different viral strains.

How It Works

RSV enters the body through the respiratory tract when viral particles are inhaled from infected respiratory droplets or contact with contaminated surfaces. The virus binds to epithelial cells in the nasal passages and travels downward to infect bronchiolar cells in the lower respiratory tract. Once inside cells, the virus replicates rapidly, causing cellular damage and inflammatory responses that produce characteristic symptoms. The immune system's response to RSV infection causes mucus production, swelling of airways, and bronchial wall thickening that impair gas exchange.

In a typical RSV infection, viral load peaks around day 5-7 after symptom onset, during which time transmission risk is highest. Healthcare facilities like long-term care centers experience significant RSV outbreaks, particularly facilities housing immunocompromised patients or those with chronic obstructive pulmonary disease (COPD). For example, a 2022 outbreak in a Seattle nursing home infected 47 residents, with 3 resulting deaths. Contact precautions and isolating infected individuals reduce transmission rates by approximately 80% in institutional settings.

The pathophysiology of RSV involves both direct viral cytopathic effects and immune-mediated tissue damage. Small airway obstruction develops from epithelial cell sloughing, mucus plugging, and subepithelial edema that narrows bronchiolar lumens. Bronchiolitis results in air trapping, ventilation-perfusion mismatch, and hypoxemia that can persist for 2-3 weeks. Elderly patients and those with underlying cardiac disease experience more severe disease progression due to diminished respiratory reserve and compromised cardiovascular compensation.

Why It Matters

RSV causes an estimated 160,000 hospitalizations and 6,000-10,000 deaths annually in adults 60+ in the United States, making it a major public health burden. Healthcare costs associated with RSV in older adults exceed $3 billion annually when accounting for hospitalizations, emergency department visits, and outpatient care. The mortality rate in hospitalized elderly patients reaches 5-10%, with rates exceeding 30% in immunocompromised populations. RSV-related complications contribute significantly to winter hospital admissions and strain on ICU capacity.

RSV complications extend across multiple industries and sectors affecting workforce productivity and healthcare systems. Long-term care facilities represent major transmission sites, with RSV outbreaks causing staff shortages as employees become infected alongside residents. Major hospital systems like Cleveland Clinic and Mayo Clinic have implemented year-round RSV surveillance protocols to prevent nosocomial transmission. Schools and daycare centers experience significant disruption when RSV circulates, with some facilities closing temporarily to control outbreaks affecting staff and families.

Future RSV prevention and treatment represents a rapidly advancing field with new vaccines, monoclonal antibodies, and antivirals under development. The 2023 FDA approval of Arexvy vaccine marked the beginning of a new era in adult RSV prevention, with studies showing 94.6% efficacy in preventing RSV lower respiratory tract disease. Monoclonal antibody treatments like RSVPreF3 are expected to provide passive immunity for high-risk adults through 2025-2026. Real-world effectiveness data from vaccination campaigns will guide public health recommendations and shape RSV management strategies in coming years.

Common Misconceptions

Many adults mistakenly believe RSV is exclusively a childhood illness, but RSV severity in older adults rivals or exceeds that seen in infants. In fact, adults 65+ experience hospitalization rates comparable to infants under 6 months of age when infected with RSV. The misconception arose because early RSV research focused primarily on pediatric populations, particularly those with congenital heart disease. Modern surveillance data clearly demonstrates that RSV causes substantial morbidity and mortality across all adult age groups, especially in those over 75.

A common myth suggests RSV immunity after childhood infection provides lifelong protection, but reinfection is actually common throughout adulthood. Adults experience an average of 3-4 RSV infections throughout their lifetime due to incomplete or waning immunity. Each reinfection can cause illness of varying severity depending on immune status and underlying conditions at time of exposure. Natural immunity from prior RSV infection does not prevent subsequent infections but may reduce symptom severity in some cases.

Many people incorrectly believe RSV transmission only occurs through direct coughing or sneezing, overlooking the significant role of contaminated surfaces. RSV remains viable on hard surfaces for up to 30 minutes and can survive on skin for several minutes, making fomite transmission common. Hand hygiene and surface disinfection are critical control measures because many RSV transmissions occur through touching contaminated surfaces then touching the face. Healthcare workers and family caregivers who don't practice meticulous hand hygiene cause the majority of transmission events in institutional settings.

Common Misconceptions