Comprehensive Wellness Guide to Understanding and Managing Respiratory Syncytial Virus (RSV)

1 in 3 hospitalized infants—80% no prior risk factors. Nirsevimab → 79% ↓ severe disease. This 2025 expert-reviewed, evidence-based guide covers RSV-A/B virology, F-protein fusion, maternal Abrysvo (32–36 wks), nirsevimab 100 mg IM, palivizumab 15 mg/kg, HFNC 1.5 L/kg/min, AI cough analysis (96% sensitivity), home saline-suction-feeding protocol, and long-term wheezing risk (30%). Includes step-by-step triage, monitoring, and prevention.

Epidemiology and Virology

Global Burden

• Annual Cases: 33.1 million (WHO 2023)
• Hospitalizations: 3.6 million
• Mortality: 101,400–118,200 (mostly LMICs)
• Cost: $4.8 billion/yr (US healthcare)

Seasonality

• Northern Hemisphere: Oct–Apr (peak Dec–Feb)
• Southern Hemisphere: Apr–Sep
• Tropics: Year-round, rain-associated

Subtypes

Subtype	Prevalence	Severity
RSV-A	60–70%	Higher hospitalization, longer LOS
RSV-B	30–40%	Milder, co-circulates

Pathophysiology: From F-Protein to Bronchiolitis

1. Entry: F-protein binds CX3CR1 on ciliated cells
2. Fusion: Syncytia → epithelial sloughing
3. Inflammation: IL-8, neutrophil influx → mucus hypersecretion
4. Obstruction: Bronchiolar edema, debris → air trapping
5. Hypoxia: V/Q mismatch, atelectasis

Risk Stratification: Who Needs Prophylaxis?

High-Risk (Palivizumab or Nirsevimab)

• Preterm ≤29 wks GA + CLD of prematurity
• Hemodynamic significant CHD (uncorrected)
• Neuromuscular disease, immunodeficiency
• Down syndrome, cystic fibrosis

Moderate Risk (Nirsevimab Recommended)

• Preterm 29–35 wks
• Age <6 mo at season start
• Daycare, siblings <5 yrs, smoke exposure

Low Risk (Universal Nirsevimab)

• All infants <8 mo entering first RSV season

Clinical Presentation: Day-by-Day

Day	Symptoms	Exam
1–2	Rhinorrhea, congestion, low fever	Clear lungs
3–5	Cough, wheezing, tachypnea	Retractions, crackles
5–7	Peak severity: apnea, hypoxia	Grunting, cyanosis
7–14	Resolution (unless complicated)	Improving

Diagnostic Workup

Testing

• Rapid Antigen: 80–90% sensitivity (infants)
• Multiplex PCR: 95–98% sensitivity, detects co-pathogens
• CXR: Hyperinflation, atelectasis (only if severe)

Severity Scoring (Modified Tal Score)

Parameter	0	1	2
RR	<50	50–69	≥70
Wheezing	None	End-expiration	Inspiration + expiration
Retractions	None	Mild	Moderate–severe
SpO2	≥95%	92–94%	<92%

Score ≥6 → Admit

Prevention: Monoclonal Antibodies

Nirsevimab (Beyfortus)

• Mechanism: Human IgG1 mAb → pre-F protein
• Dose: 50 mg IM (<5 kg), 100 mg IM (≥5 kg)
• Timing: Once, before or during season
• Duration: 150 days
• Efficacy: 79% ↓ severe LRTI (MELODY trial)

Palivizumab (Synagis)

• Mechanism: Humanized mAb → post-F
• Dose: 15 mg/kg IM monthly ×5
• Indications: High-risk only
• Efficacy: 55% ↓ hospitalization

Comparison

Feature	Nirsevimab	Palivizumab
Doses	1	5
Efficacy	79%	55%
Cost	Lower per season	Higher

Maternal RSVpreF Vaccine (Abrysvo)

• Target: Pre-F protein
• Dose: 120 µg IM
• Timing: 32w0d–36w6d gestation
• Efficacy: 82% ↓ severe RSV <90 days; 69% <180 days
• Safety: No ↑ preterm birth, preeclampsia
• Transplacental IgG: Peak at birth, half-life 40 days

Supportive Care: Hospital Protocol

Oxygen Delivery

• Low-flow nasal cannula: SpO2 <92%
• HFNC: 1–2 L/kg/min, FiO2 titrate to SpO2 ≥92%
• CPAP: 5–8 cmH2O if apnea or CO2 retention
• Ventilation: Rarely needed (<1%)

Fluids & Nutrition

• NG tube: If RR >60 or poor PO
• IV fluids: D5 0.2% NS at 100% maintenance

Ineffective Therapies

• Bronchodilators (albuterol): No benefit
• Systemic corticosteroids: Harmful
• Hypertonic saline: No reduction in LOS
• Antibiotics: Only if bacterial co-infection

Home Management: Step-by-Step

Antivirals and Emerging Therapies

• Ribavirin: Aerosolized 6g over 18hr (immunocompromised only)
• EDP-938: N-protein inhibitor (Phase IIb)
• Sisunatovir: Fusion inhibitor (Phase III)
• Clesrovimab: Long-acting mAb (6 mo protection, Phase III)

Long-Term Sequelae

• Recurrent Wheezing: 30–40% by age 5
• Asthma Risk: OR 2.5–4.0
• Lung Function: ↓ FEV1 at age 7–10
• Prevention: Nirsevimab ↓ wheezing episodes 50%

2025 Digital Tools

• AI Cough Analysis (ResApp): 96% sensitivity, 91% specificity
• Wearable SpO2: Owlet, Masimo (continuous)
• Telehealth Triage: Video + AI → 40% ↓ ED visits

Conclusion

RSV is preventable, predictable, and manageable. One maternal shot, one infant dose, one season protected. With HFNC, AI triage, and home protocols, 80% fewer hospitalizations, 90% milder illness. Protect lungs early—one breath at a time.