Disease Profile

Pathogen

• Respiratory Syncytial Virus (RSV), Human orthopneumovirus
• Negative sense (-), single-stranded RNA
• Non-segmented genome – unlike influenza, RSV cannot differentiate into various subtypes
• Two subtypes: A and B

Transmission

• Infection via contaminated droplets circulated by coughing or sneezing
• Can survive on surfaces for 25 minutes
• Incubation period of 2 to 8 days
• An infected individual can remain contagious for 3 to 8 days

Symptomology

• Nasal congestion, Runny nose, Cough, Low-grade fever, Wheezing
• Due to similarities in symptomology, children between 1 and 5 years old may need differential tests for respiratory illnesses
• RSV infects the respiratory tract. If left untreated, 15-50% will develop a serious lower respiratory tract infection such as bronchiolitis, viral pneumonia, or croup

Seasonal Trends

• RSV season onset: mid-September to mid-November
• RSV season peak: late December to mid-February
• RSV season offset: mid-April to mid-May
• Patterns of circulation have been disrupted since the start of the COVID-19 pandemic (2020). RSV in southern regions begins to rise in spring and peaks in July

Globally, RSV was estimated to have caused 66,000 to 199,000 pneumonia deaths in children less than 5 years old in 2005, making RSV the third most important cause of deadly childhood pneumonia after Streptococcus pneumonia and Haemophilus influenza^[1]

High Risk Populations^[1]

• Infants and young children
• Older adults, especially those 65 years and older

Epidemiology (United States)

• Most children under the age of 2 will be infected with RSV at least once.^[2]
• Leading cause of lower respiratory tract illness in infants (0-1 Years)
  - Infant hospitalization rate, 0-1 years: 2,345 per 100,000 (151 for Influenza viruses)
  - Total hospitalization rate, all age groups: 55 per 100,000 (64 for Influenza viruses)
• 1 in 13 children under the age of five requires medical attention for RSV each year
  - 60% of office visits were for 2-5-year-olds

CDC Burden Estimates^[3]

• Each year in the United States, RSV leads to approximately:
• 2.1M outpatient (non-hospitalization) visits among children <5 years old.
• 58,000-80,000 hospitalizations among children <5 years old.
• 60,000-160,000 hospitalizations among adults 65 years and older.
• 6,000-10,000 deaths among adults 65 years and older.
• 100–300 deaths in children younger than 5 years old.