Respiratory Syncytial Virus

from https://www.ncbi.nlm.nih.gov/books/NBK459215/

RSV: common virus infecting children and adults, especially the elderly.
Common clinical presentation: upper respiratory infection, bronchiolitis in children.
Severe cases: pneumonia, respiratory failure, apnea, death.
Mainstay of treatment: supportive care.
Passive immunization: available for at-risk children.
Antiviral treatment: limited by efficacy, side effects, and cost.
Interprofessional team: essential for management, care coordination, and improved outcomes.

Introduction

RSV: widespread virus infecting children and elderly.
Commonly presents: as upper respiratory infection; in young children, often causes bronchiolitis.
Severe cases: can lead to pneumonia, respiratory failure, apnea, and death.
Treatment: mainly supportive; passive preventive immunization available for at-risk children.
Antiviral treatment: ribavirin, used on a case-by-case basis due to limited efficacy and high cost.

Etiology

RSV: single-stranded RNA virus, Paramyxoviridae family, Pneumovirus genus.
Discovered: in 1955 in chimpanzees, confirmed in humans shortly after.
Structure: bilipid-layer envelope, ribonucleoprotein core, membrane proteins (attachment and fusion).
Serotype and strains: one serotype, two strains (A and B) with structural protein variations.

Epidemiology

Lack of long-term immunity: frequent reinfections.
Infection rate: 90% of children within first 2 years.
Lower respiratory tract illness: significant minority of cases, primarily bronchiolitis.
High-risk groups: premature infants, cardiac, pulmonary, neurologic, immunosuppressive disorders, elderly.
Global impact: 33 million lower respiratory tract illnesses, 3 million hospitalizations, up to 199,000 childhood deaths annually.
Seasonal variation: winter-spring in temperate climates, less pronounced in tropical climates.

Pathophysiology

Transmission: respiratory droplets.
Incubation period: 2-8 days (mean 4-6 days).
Target cells: apical ciliated epithelial cells in respiratory tract.
Viral entry: RSV-G glycoprotein for attachment, RSV-F glycoprotein for fusion.
Immune response: humoral and cytotoxic T-cell activation.
Consequences: small airway obstruction, mucus plugging, ciliary dysfunction, airway edema, decreased lung compliance.

Histopathology

Severe disease findings: abundant respiratory epithelial cell death, airway edema, immune cell infiltration (polymorphonuclear early, lymphomononuclear later).

History and Physical

Upper respiratory illness: rhinorrhea, nasal congestion, cough, sneezing, fever, myalgia.
Lower respiratory involvement: rhonchorous breath sounds, tachypnea, accessory muscle use, wheezes, prolonged expiration.
Severe cases: viral pneumonia, hypoxia, lethargy, apnea, acute respiratory failure.

Evaluation

Clinical diagnosis: no confirmatory testing required.
Specific testing: rapid antigen and PCR testing.
- Antigen testing: quick, inexpensive, specific, ~80% sensitivity.
- PCR testing: more sensitive, can detect multiple organisms, higher cost, requires specialized equipment.
Radiographic findings: hyperinflation, patchy atelectasis, peribronchial thickening.

Treatment / Management

Supportive care:
- Nasal suction and lubrication.
- Antipyretics for fever.
- Assisted hydration: oral, nasogastric tube, or intravenous.
- Oxygen for hypoxia.
- Ventilatory support: high-flow nasal cannula, CPAP, intubation, mechanical ventilation.
Immune prophylaxis: palivizumab for at-risk infants.
- Palivizumab: humanized murine monoclonal antibody, monthly administration during RSV season.
Antiviral medication: ribavirin (case-by-case basis).
Other treatments: albuterol, racemic epinephrine, steroids, hypertonic saline, antibiotics, chest physical therapy (not recommended).

Differential Diagnosis

Asthma
Bronchiolitis
Influenza
Croup
Bronchitis
Pneumonia

Prognosis

Excellent outcome: for most children.
Hospitalization: typically 3-4 days.
High-risk infants: longer stays, higher rates of mechanical ventilation and ICU admission.
Mortality: less than 1%, <400 deaths/year in the US.

Deterrence and Patient Education

Hand washing: critical for prevention.
Hygiene practices: avoid sharing drinks/utensils, clean surfaces, isolate infected individuals.

Pearls and Other Issues

Severe RSV infection: increases risk for recurrent wheezing, childhood asthma, allergic sensitization.
Palivizumab prophylaxis: may decrease incidence of recurrent wheezing.

Outcomes

Majority of children: excellent outcome.
High-risk infants: longer admissions, potential need for mechanical ventilation.
Long-term: possible wheezing, but recent studies show no increased asthma risk

RSV immunisation

https://www.vaccinate.initiatives.qld.gov.au/what-to-vaccinate-against/rsv-immunisation

Queensland, August 2026

Available products

Abrysvo®

RSV vaccine.
Used during pregnancy and in adults aged ≥60 years.
Only RSV vaccine recommended and funded during pregnancy.
Not registered for administration to infants or children.

Nirsevimab — Beyfortus®

Long-acting RSV-specific monoclonal antibody; not a vaccine.
Provides passive protection against severe RSV disease for at least five months.
Used in eligible infants and children aged from birth to <24 months.
Not registered for adults.

Arexvy®

Adjuvanted RSV vaccine for adults.
Not registered for pregnancy, infants or children.
NIP-funded for adults aged ≥75 years and Aboriginal and Torres Strait Islander adults aged ≥60 years.

Pregnancy

Abrysvo is recommended during every pregnancy from 28 weeks gestation.
Ideally administer between 28 and 36 weeks and at least 14 days before birth.
If missed by 36 weeks, administer as soon as possible.
Given year-round.
Protects the infant from birth for approximately six months.
Funded under the National Immunisation Program for Medicare-eligible pregnant women.
Infants adequately protected through maternal Abrysvo do not routinely require nirsevimab.

Nirsevimab: infants from birth to <8 months

Funded through the Queensland Paediatric RSV Prevention Program for infants living in Queensland when:

Maternal Abrysvo was not administered.
Birth occurred within 14 days of maternal Abrysvo.
Maternal RSV vaccination status is unknown.
Maternal immunosuppression may have impaired antibody transfer.
The infant may have lost passive antibodies following exchange transfusion, cardiopulmonary bypass, ECMO or a similar procedure.
The infant has a condition associated with increased risk of severe RSV disease, regardless of maternal vaccination.

Additional information:

Medicare eligibility is not required.
Program operates year-round.
Offer eligible newborns nirsevimab before discharge from the birthing hospital.
If not given in hospital, it can be administered through primary care before the infant reaches eight months.
Once the infant reaches eight months, they are no longer eligible under the first-season criteria.

Nirsevimab: children aged 8 to <24 months

Recommended before the second RSV season for children with a condition associated with increased risk of severe RSV disease.

Give regardless of maternal RSV vaccination status.
Give regardless of whether nirsevimab was administered during the first RSV season.
Allow at least six months after the previous nirsevimab dose.
Time administration to maximise protection during the anticipated RSV season.
The child is no longer eligible after reaching 24 months.

Conditions associated with increased risk of severe RSV disease

Premature birth at <32 weeks gestation.
Haemodynamically significant congenital heart disease.
Chronic lung disease requiring ongoing oxygen or respiratory support.
Significant immunosuppression, including:
- severe primary immunodeficiency
- active chemotherapy
- solid-organ transplantation
- haematopoietic stem-cell transplantation.
Neurological or neuromuscular conditions impairing respiratory function.
Cystic fibrosis with severe lung disease or weight-for-length below the 10th percentile.
Trisomy 21 or another genetic condition associated with increased RSV risk.
Other significant conditions in children aged <24 months following discussion with a paediatric infectious diseases specialist.

Nirsevimab dosing

Age <8 months and weight <5 kg: 50 mg IM once.
Age <8 months and weight ≥5 kg: 100 mg IM once.
High-risk child aged 8 to <24 months: 200 mg IM, administered as two separate 100 mg injections.
Dose according to weight at the time of administration.
Preferred injection site: anterolateral thigh.
May be administered with routine childhood vaccines using separate injection sites.
If two syringes are required, record a single nirsevimab dose on the Australian Immunisation Register.

Previous or current RSV infection

Previous laboratory-confirmed RSV infection does not remove eligibility.
Eligible children may receive nirsevimab once recovered.
Defer administration during moderate or severe acute illness, including active RSV infection, until clinically recovered.

Adults

Adults aged ≥75 years

One dose of Arexvy is recommended and funded under the NIP for Medicare-eligible people.
Abrysvo is registered but not NIP-funded.
The need for repeat or booster doses has not yet been established.

Aboriginal and Torres Strait Islander adults aged ≥60 years

One dose of Arexvy is recommended and NIP-funded for Medicare-eligible people.
Abrysvo is registered but not NIP-funded.

Other adults aged 60–74 years

RSV vaccination is recommended for people with medical conditions or other risk factors for severe RSV disease.
Adults without recognised risk factors may consider vaccination following individual risk–benefit discussion.
Arexvy and Abrysvo are registered but are not routinely NIP-funded for non-Indigenous adults in this age group.

Adults aged 50–59 years

Arexvy is registered for adults with an increased risk of severe RSV disease.
It is not NIP-funded.
Abrysvo is not registered for this age group.

Administration with other vaccines

RSV vaccines and nirsevimab may generally be given with other indicated vaccines.
Use separate syringes and different injection sites.
Co-administration may increase short-lived local or systemic adverse effects.