Respiratory

RSV vaccine in older adults and pregnancy

Clinical Overview and When to Suspect RSV in Vaccine-Eligible Adults

— ~60,000–160,000 hospitalizations and 6,000–10,000 deaths annually in US adults ≥65

— Comparable mortality to influenza in older adults with cardiopulmonary comorbidity

— Age ≥75 years (universal recommendation)

— Age 50–74 with risk factors: COPD, asthma, CHF, CAD, CKD, diabetes with end-organ damage, chronic liver disease, immunocompromise, severe obesity (BMI ≥40), residence in nursing facility, advanced frailty

— Older adult with wheezing, new oxygen requirement, or COPD/CHF exacerbation during RSV season

— Nursing home outbreak of febrile cough illness with negative influenza/COVID testing

— Infant <6 months with apnea, poor feeding, retractions, or bronchiolitis (drives the maternal vaccine rationale)

— RSVPreF3 (Arexvy, GSK) — adjuvanted, adults ≥60 with shared decision-making for 50–59 high-risk

— RSVpreF (Abrysvo, Pfizer) — non-adjuvanted, adults ≥60 and pregnancy 32–36 weeks

— mRNA-1345 (mResvia, Moderna) — adults ≥60

Respiratory syncytial virus (RSV) is a single-stranded RNA paramyxovirus causing seasonal lower respiratory tract infection (LRTI) with peaks November–March in the US.

Historically framed as a pediatric pathogen, RSV is now recognized as a major cause of adult morbidity:

High-risk adult groups (drive vaccine prioritization):

Why suspect RSV in clinic or on the wards:

Vaccine landscape (as of current ACIP guidance):

Board pearl: RSV in adults is a clinical syndrome of bronchospasm + hypoxemia more than coryza; suspect it when "flu-like" illness is PCR-negative for influenza and SARS-CoV-2 in an older adult during winter.

Step 3 management: Always pair RSV vaccine counseling with influenza, COVID-19, pneumococcal, and Tdap status review — Step 3 loves the bundled preventive visit.

Presentation Patterns and Key History

— Mild upper respiratory tract infection: rhinorrhea, sore throat, low-grade fever, hoarseness

— Tracheobronchitis with prolonged post-viral cough (2–4 weeks)

— Lower respiratory tract disease: dyspnea, wheeze, hypoxemia, sometimes without fever

— Triggered exacerbations of COPD, asthma, or decompensated heart failure

— Incubation 2–8 days, viral shedding 3–8 days (longer in immunocompromised, up to 3–4 weeks)

— Older adults often present late (day 5–7) when LRTI manifests

— Maternal vaccination at 32 0/7–36 6/7 weeks transfers transplacental antibodies to protect infants from birth to ~6 months

— Counsel mothers that infant RSV LRTI in the first months of life presents with apnea, grunting, nasal flaring, poor feeding, and tachypnea — fever may be absent

— Vaccination history: prior RSV vaccine receipt (one-time dose, no annual revaccination currently recommended)

— Immunocompromise: solid organ transplant, hematologic malignancy, B-cell-depleting therapy, advanced HIV

— Pregnancy gestational age and prior nirsevimab plan for the infant

— Living situation: long-term care facility, multigenerational household with young children (RSV reservoir)

Older adult RSV presents along a spectrum:

Symptom timeline:

Pregnancy and the neonate (vaccine indication context):

High-yield history elements for the Step 3 ambulatory visit:

Key distinction: One-time dosing. As of current ACIP language, RSV vaccine in adults ≥75 (or 60–74 high-risk) is a single lifetime dose — not annual like influenza. Stems that suggest "give again next year" are wrong.

Board pearl: A grandmother caring for daycare-age grandchildren is a classic stem cue for prioritizing RSV vaccination and emphasizing hand hygiene as adjunct prevention.

Physical Exam Findings and Hemodynamic Assessment

— Tachypnea (RR >22), accessory muscle use

— Diffuse expiratory wheeze — more prominent than in flu

— Coarse crackles at bases if bronchiolitis or superimposed bacterial pneumonia

— Prolonged expiratory phase

— SpO2 on room air — <92% triggers admission consideration

— Heart rate, blood pressure, mental status (qSOFA), capillary refill

— Volume status: JVP, peripheral edema — RSV frequently unmasks heart failure

— Nasal flaring, intercostal/subcostal retractions, head bobbing

— Apnea in neonates <2 months (red flag)

— Wheeze + crackles + prolonged expiration = bronchiolitis pattern

— Routine prenatal exam; document fundal height, fetal heart tones, BP screening for pre-eclampsia

— No specific RSV-related exam change post-vaccination beyond local injection-site assessment

— Injection-site pain (~60%), fatigue, headache, myalgia, arthralgia within 1–3 days

— Low-grade fever in <5%

— No expected wheeze, rash, or systemic illness — these warrant evaluation for alternative cause

Adult RSV LRTI physical findings overlap with influenza and COVID-19 but skew toward lower airway obstruction:

Hemodynamic and oxygenation assessment in the older adult:

Pediatric exam reference (for the post-maternal-vaccine infant who still gets RSV):

Pregnant patient receiving the vaccine:

Vaccine reactogenicity exam findings (counsel and document):

Step 3 management: In an older adult with new wheeze and hypoxemia during winter, simultaneously test for influenza, SARS-CoV-2, and RSV — multiplex PCR — and do not anchor on COPD exacerbation alone. The exam finding of wheeze does not exclude viral LRTI; it suggests it.

Board pearl: Bilateral wheeze + hypoxemia + negative flu/COVID in a vaccinated elderly patient = think RSV; check whether their one-time RSV vaccine was actually given or just "offered."

Diagnostic Workup — Initial Labs, Imaging, and Virologic Testing

— Multiplex respiratory PCR (RSV, influenza A/B, SARS-CoV-2 ± other viruses) from nasopharyngeal swab — high sensitivity in adults

— Rapid antigen tests for RSV have poor sensitivity in adults (<40%) — useful in kids, unreliable in elderly; do not exclude RSV with a negative antigen

— CBC: lymphopenia common; leukocytosis suggests bacterial superinfection

— BMP: assess AKI, hyponatremia (SIADH can accompany severe LRTI)

— CRP/procalcitonin: procalcitonin <0.25 ng/mL supports viral etiology and helps withhold antibiotics

— Lactate if sepsis physiology

— BNP/NT-proBNP if cardiac comorbidity to disentangle CHF

— Troponin if chest pain or dyspnea out of proportion — viral illness can precipitate type 2 MI

— Chest X-ray: often normal or shows peribronchial thickening, patchy interstitial opacities, or hyperinflation; focal consolidation suggests bacterial co-infection

— Chest CT reserved for diagnostic uncertainty, suspected PE, or immunocompromised host

— No labs required before RSV vaccine administration

— Pregnancy: confirm gestational age 32 0/7–36 6/7 weeks; review prenatal vaccination record

RSV is a clinical-plus-PCR diagnosis in adults. Step 3 stems rarely require viral culture or serology.

First-line virologic testing:

Supporting initial labs in the symptomatic older adult:

Imaging:

Pre-vaccination workup (ambulatory visit):

CCS pearl: On a CCS case with elderly winter pneumonia, order "respiratory viral panel PCR" and "procalcitonin" early — they justify de-escalating empiric antibiotics by day 2–3 if RSV-positive and procalcitonin low.

Key distinction: Antigen tests are fine for pediatric RSV (high viral load) but inadequate in adults — always confirm with PCR if antigen is negative and suspicion remains.

Diagnostic Workup — Advanced or Confirmatory Studies and Vaccine-Related Evaluation

— Hypoxemia refractory to low-flow O2

— Immunocompromise (transplant, hematologic malignancy, anti-CD20 therapy)

— Persistent fever or clinical worsening after 72 hours

— Chest CT: ground-glass opacities, tree-in-bud, bronchiolitis pattern; rule out PE, ARDS

— Blood and sputum cultures if bacterial superinfection suspected (S. pneumoniae, S. aureus, H. influenzae classic)

— Echocardiography if new heart failure or troponin elevation

— ABG if respiratory distress to assess hypercapnia (especially COPD overlap)

— Lower respiratory tract sampling (BAL) may be needed; upper airway PCR can miss lower tract RSV

— Quantitative RSV PCR can guide duration of isolation and infectivity in transplant units

— Do not check RSV serology before vaccination

— Do not delay vaccine for mild URI; defer only for moderate-severe acute illness or fever

— Do not co-administer with other vaccines reflexively in pregnancy without weighing reactogenicity (some experts space RSV and Tdap by ≥2 weeks to attribute reactions, though co-administration is permitted)

— Guillain-Barré syndrome (GBS) — small numerical imbalance observed post-licensure for RSVPreF3 and RSVpreF in adults ≥60; absolute risk very low (~1–9 per million doses). Disclose during shared decision-making.

— Atrial fibrillation signal in some trials — not confirmed causal

— Maternal vaccine and preterm birth: Pfizer trial showed numerical imbalance — hence the 32–36 week window, avoiding earlier administration

Most adults need no studies beyond PCR and CXR. Escalate workup when:

Advanced testing in severe or atypical RSV:

Immunocompromised hosts:

Pre-vaccination "advanced" considerations — what NOT to do:

Safety surveillance signals to know:

Board pearl: The reason Abrysvo is given only at 32–36 weeks gestation (not earlier) is to minimize potential preterm birth signal while maximizing transplacental antibody transfer.

Step 3 management: Document shared decision-making conversations about GBS risk for adults 60–74; this is testable as informed consent quality.

Risk Stratification and Vaccination Decision Logic

— Age ≥75: universal recommendation, single dose

— Age 60–74 with increased risk: recommended (no longer "shared clinical decision-making" — simplified to risk-based recommendation)

— Age 50–59 with increased risk: recommended in updated guidance (expanded eligibility)

— Pregnancy 32 0/7–36 6/7 weeks during September–January (seasonal): RSVpreF (Abrysvo) — the only RSV vaccine approved in pregnancy

— Chronic lung disease (COPD, asthma, ILD, cystic fibrosis)

— Cardiovascular: CHF, CAD, congenital heart disease

— Moderate–severe immunocompromise

— Diabetes mellitus with complications

— CKD, chronic liver disease

— Hematologic disorders, severe obesity (BMI ≥40)

— Neurologic/neuromuscular conditions compromising airway clearance

— Residence in long-term care

— Maternal RSVpreF at 32–36 weeks during RSV season, OR

— Nirsevimab (monoclonal antibody) to the infant <8 months entering first RSV season

— Use nirsevimab if mother was not vaccinated, vaccinated <14 days before delivery, has conditions reducing antibody transfer, or infant has high-risk conditions

— Administer late summer to early fall (August–October ideal) to cover winter peak

— One-time dose currently; future ACIP updates may revisit revaccination interval

ACIP framework (current):

"Increased risk" conditions justifying vaccination in 50–74 group:

Infant protection strategy — either/or, not both routinely:

Timing logic:

Key distinction: Maternal vaccine vs. nirsevimab — Step 3 tests this: mother vaccinated ≥14 days before delivery in season → infant does not routinely need nirsevimab. Mother unvaccinated → infant needs nirsevimab.

Step 3 management: Build RSV vaccination into the Medicare Annual Wellness Visit workflow — it's covered under Part D with $0 cost-sharing under the Inflation Reduction Act.

Pharmacotherapy — Vaccine Products, Dosing, and Administration

— RSVPreF3 (Arexvy, GSK): adjuvanted (AS01E) prefusion F protein, single 0.5 mL IM dose, adults ≥60

— RSVpreF (Abrysvo, Pfizer): non-adjuvanted bivalent (RSV A + B) prefusion F, single 0.5 mL IM dose, adults ≥60 and pregnancy 32–36 weeks

— mRNA-1345 (mResvia, Moderna): lipid nanoparticle mRNA encoding prefusion F, single 0.5 mL IM, adults ≥60

— Deltoid IM injection, 23–25 gauge, 1–1.5 inch needle

— Store refrigerated 2–8°C; do not freeze

— Reconstitute per product (Arexvy and Abrysvo are lyophilized + diluent)

— Permitted with influenza, COVID-19, pneumococcal, Tdap, shingles vaccines — use separate anatomic sites

— In pregnancy: Tdap and RSV can be co-administered, though some clinicians space by 2 weeks to attribute local reactions

— Reactogenicity may be slightly higher with co-administration but not clinically significant

— Severe allergic reaction (anaphylaxis) to prior dose or component

— History of GBS is a precaution (not absolute contraindication) — individualize

— Moderate-to-severe acute illness with or without fever — defer until recovered

— Pregnancy <32 weeks for Abrysvo — do not administer early due to preterm birth signal

— Arexvy and mResvia are not approved in pregnancy — do not substitute

— Common: injection-site pain, fatigue, myalgia, headache (peak 24–48h, resolve in 1–3 days)

— Rare serious: GBS (~1–9/million), inflammatory neurologic events, anaphylaxis

Three FDA-approved adult RSV vaccines:

Administration practicalities:

Co-administration:

Contraindications:

Precautions:

Adverse effects:

Board pearl: Only Abrysvo (RSVpreF) is approved in pregnancy. If the stem says "GSK vaccine in 34-week pregnant patient" — that's wrong; switch to Pfizer's Abrysvo.

Step 3 management: Document lot number, site, date, and VIS provision in the EHR — required for Vaccine Adverse Event Reporting System (VAERS) traceability.

Treatment of Established RSV Infection (Adjunctive to Prevention Focus)

— Hydration, antipyretics (acetaminophen preferred in CKD/anticoagulated)

— Symptomatic care: saline nasal spray, honey for cough (>1 year old)

— Return precautions: dyspnea, SpO2 <94%, chest pain, confusion

— Supplemental O2 to keep SpO2 ≥92% (≥88% in COPD)

— High-flow nasal cannula (HFNC) for moderate hypoxemic respiratory failure

— Non-invasive ventilation (BiPAP) for hypercapnic COPD overlap

— Mechanical ventilation if refractory

— Bronchodilators (albuterol ± ipratropium) — empiric trial if wheezing; continue only if objective response

— Systemic corticosteroids — not routinely recommended for RSV alone; use if COPD/asthma exacerbation criteria met (prednisone 40 mg × 5 days)

— Antibiotics — only if bacterial co-infection suggested (focal consolidation, elevated procalcitonin, leukocytosis with left shift); cover S. pneumoniae and consider S. aureus post-viral

— Ribavirin — limited to select immunocompromised (stem cell transplant) — specialist-driven, not Step 3 first-line

— Palivizumab/nirsevimab — pediatric prophylaxis only, not treatment

— Supportive care, suction, hydration

— No routine bronchodilators, steroids, epinephrine, or antibiotics in typical bronchiolitis (AAP guideline)

— Hospitalize for hypoxemia, apnea, dehydration, or respiratory distress

No specific approved antiviral for adult RSV. Management is supportive.

Outpatient mild RSV (vaccinated or unvaccinated adult):

Inpatient moderate-severe RSV LRTI:

Pharmacologic adjuncts:

Pediatric/infant RSV (relevant for the post-maternal-vaccine breakthrough case):

CCS pearl: For an admitted older adult with RSV LRTI, the high-yield orders are: isolation (droplet + contact), oxygen, IV fluids, monitor SpO2/RR, hold β-blocker if bronchospasm severe, avoid empiric ceftriaxone+azithromycin reflexively if PCR confirms RSV and procalcitonin is low.

Board pearl: RSV is not influenza — oseltamivir does nothing. Test stems may bait this.

Special Populations — Elderly and Renal/Hepatic Impairment

— Highest hospitalization and mortality rates

— Single lifetime dose currently; revaccination not recommended (durability data ongoing, protection demonstrated through ≥2 seasons)

— Vaccinate even in advanced age and frailty if life expectancy >6 months and patient/surrogate consents

— Long-term care facility residents are high priority — outbreaks are devastating

— Coordinate vaccination with facility medical director and use standing orders

— No dose adjustment for RSV vaccines

— Dialysis patients are high-risk and should be vaccinated; administer on non-dialysis day to avoid attributing reactogenicity to dialysis

— Avoid IM injection into AV fistula arm

— No dose adjustment

— Chronic liver disease (cirrhosis) is itself an indication for vaccination in 50–74 group

— Patients on warfarin, DOACs, or antiplatelets can receive IM RSV vaccine

— Use 23–25 gauge needle, firm pressure ≥2 minutes post-injection

— INR within therapeutic range is acceptable; no need to hold anticoagulation

— Adjuvanted vaccine (Arexvy) may offer enhanced response in older adults, similar to high-dose flu rationale — though head-to-head data limited

— Antibody titers wane more slowly than expected; durability is a strength of prefusion F vaccines

— Use vaccination encounter to review Beers criteria meds, fall risk, advance directives

Adults ≥75 are the primary target of RSV vaccination:

Frailty considerations:

Renal impairment:

Hepatic impairment:

Anticoagulation:

Immunosenescence:

Polypharmacy and the Step 3 wellness visit:

Step 3 management: A 78-year-old with COPD, CKD stage 4, on apixaban presents for annual visit in September — administer RSV vaccine (one-time), influenza, and ensure pneumococcal (PCV20 or PCV15+PPSV23) and shingles are updated. No dose adjustments needed.

Board pearl: Frailty is not a contraindication — it is an indication. The sickest are the ones who benefit most absolutely.

Special Populations — Pregnancy, Pediatrics, and Immunocompromised

— RSVpreF (Abrysvo) only, single 0.5 mL IM dose at 32 0/7 to 36 6/7 weeks

— Administer during September–January (seasonal); outside this window, plan nirsevimab for the infant

— Co-administration with Tdap and influenza permitted; spacing optional

— Counsel about transient injection-site reactions; no increased risk of pre-eclampsia, gestational HTN, or fetal anomalies in trials

— Preterm birth signal led to gestational age restriction — do not administer before 32 weeks

— Maternal vaccination ≥14 days before delivery during RSV season → infant generally does not need nirsevimab

— Maternal vaccination <14 days before delivery, no vaccination, or maternal condition impairing antibody transfer → infant receives nirsevimab 50–100 mg IM (weight-based) before/during first RSV season

— High-risk infants (preterm, CHD, CLD) entering second season may receive nirsevimab again

— RSV vaccines are not approved in children

— Prevention is via maternal vaccine or nirsevimab monoclonal

— Older infants/toddlers rely on environmental measures (handwashing, avoiding sick contacts, smoke-free home)

— Vaccinate (50–74 risk group or ≥75)

— Response may be blunted in B-cell-depleted patients (rituximab, BTK inhibitors) — vaccinate when possible during a treatment gap

— Solid organ and stem cell transplant: per transplant center protocols, generally vaccinate ≥3–6 months post-transplant

— RSV vaccines compatible with breastfeeding

Pregnancy:

Infant protection cascade:

Pediatrics:

Immunocompromised adults:

Lactation:

Key distinction: Maternal vaccine vs. nirsevimab is either/or. Giving both is not standard and not cost-effective; Step 3 vignettes often test this allocation logic.

Board pearl: A 34-week pregnant patient in October — give Abrysvo now. A 30-week pregnant patient in October — wait until 32 weeks; do not give Arexvy as substitute.

Complications and Adverse Outcomes

— Acute respiratory failure requiring HFNC, NIV, or intubation

— Bacterial superinfection — S. pneumoniae, S. aureus (including MRSA), H. influenzae

— Exacerbation of COPD, asthma, CHF — RSV is a leading trigger

— Acute cardiac events: acute MI, decompensated heart failure, new atrial fibrillation (~1 in 4 hospitalized older adults has a cardiac event)

— Acute kidney injury, often pre-renal from volume depletion

— Prolonged post-viral cough and airway hyperresponsiveness (weeks)

— Mortality in hospitalized adults ≥65: ~5–10%, higher in immunocompromised

— Apnea (especially <2 months, preterm)

— Bronchiolitis with respiratory failure

— Long-term recurrent wheezing/asthma association

— Reactogenicity: local pain (most common), fatigue, myalgia, headache — self-limited

— Guillain-Barré syndrome: rare numerical imbalance post-licensure; absolute risk ~1–9/million; counsel during consent

— Atrial fibrillation: small imbalance in some trials, not established as causal

— Anaphylaxis: very rare; observe 15 minutes post-injection if prior allergy history

— Maternal vaccine: preterm birth signal mitigated by 32-week threshold; no fetal malformations

— Hospitalization, ICU admission, prolonged disability, post-acute SNF placement

— Functional decline in elderly is often the lasting harm — not always death

RSV infection complications in adults:

Infant complications (driving maternal vaccination):

Vaccine-related adverse events:

Missed-opportunity complications (preventive medicine framing):

Step 3 management: Hospitalized RSV patient develops new-onset AF with rapid ventricular response — manage rate control (cautious β-blocker if no severe bronchospasm; otherwise diltiazem if EF preserved), anticoagulation per CHA2DS2-VASc, and treat the underlying viral illness. Do not anchor on AF alone.

Board pearl: RSV is a cardiopulmonary stress test — a quarter of hospitalized older adults have a cardiac event; check troponin and ECG on admission.

When to Escalate Care — ICU, Consult, and Triage Decisions

— SpO2 <92% on room air (or drop from baseline)

— RR >30, accessory muscle use, inability to speak full sentences

— Altered mental status, hypotension, lactate elevation

— Inability to maintain hydration or oral intake

— Severe comorbidity decompensation (CHF, COPD exacerbation requiring NIV consideration)

— Frail elderly with poor home support

— Persistent hypoxemia despite HFNC FiO2 >50%

— Hypercapnia with pH <7.30 not responding to NIV

— Hemodynamic instability, sepsis with end-organ dysfunction

— Need for intubation or vasopressors

— Pulmonology for refractory bronchospasm, suspected superimposed ILD, or immunocompromised host

— Infectious disease for immunocompromised, transplant, or atypical course

— Cardiology for new AF, troponin elevation, or decompensated CHF

— Maternal-fetal medicine for pregnant patient with severe RSV LRTI

— Droplet + contact precautions for hospitalized RSV

— Cohort RSV-positive patients; private room preferred

— Healthcare worker masking, hand hygiene; visitor restrictions during outbreaks

— Long-term care facility outbreaks: notify public health, implement testing of symptomatic residents/staff, restrict communal activities

— Pregnant patient with RSV LRTI and hypoxemia → admit, MFM consult, continuous fetal monitoring if viable gestation, antenatal corticosteroids if delivery anticipated 24–34 weeks

Outpatient → inpatient triage:

Floor → ICU escalation triggers:

Consults:

Infection control:

Pregnancy escalation:

CCS pearl: On a CCS RSV case, early orders for droplet/contact isolation, SpO2 monitoring, IV fluids, and respiratory viral PCR score well. Escalate location (floor → step-down → ICU) before the patient codes; the clock is moving.

Step 3 management: A nursing home resident with confirmed RSV and SpO2 88% on RA — admit, do not "treat in place" unless goals of care explicitly dictate comfort-focused approach (revisit advance directive).

Key Differentials — Same-Category (Viral Respiratory) Causes

— Abrupt onset, high fever, myalgia, headache prominent

— Treat with oseltamivir if within 48 hours (or any time in hospitalized/high-risk)

— Vaccine annual; antivirals available — distinguishes from RSV management

— Variable presentation; anosmia/ageusia historical clue

— Treat eligible outpatients with nirmatrelvir-ritonavir within 5 days

— Hospitalized hypoxemic: dexamethasone ± remdesivir ± baricitinib/tocilizumab

— Distinct vaccine schedule (updated annually)

— Paramyxovirus, RSV-like clinical picture in elderly and immunocompromised

— No vaccine, no specific antiviral

— Often on multiplex PCR — recognize and treat supportively

— Croup in children; LRTI in immunocompromised adults

— Supportive care

— Usually URI; can trigger COPD/asthma exacerbations

— No specific therapy

— Pharyngoconjunctival fever, occasionally severe pneumonia (military recruits, immunocompromised)

— Supportive; cidofovir in severe immunocompromised cases

— Wheeze prominence → favors RSV, hMPV

— High fever + myalgias → favors influenza

— Anosmia → favors COVID

— Conjunctivitis + pharyngitis → favors adenovirus

— Definitive: multiplex PCR

Influenza A/B:

SARS-CoV-2 (COVID-19):

Human metapneumovirus (hMPV):

Parainfluenza:

Rhinovirus/enterovirus:

Adenovirus:

Differentiating clinically:

Key distinction: Influenza and COVID-19 have specific antivirals; RSV does not. A positive RSV PCR should prompt de-escalation of empiric oseltamivir and confirmation that nirmatrelvir-ritonavir is not indicated.

Board pearl: When a stem describes "winter respiratory virus with wheeze, negative flu and COVID" — RSV is the answer until proven otherwise.

Key Differentials — Other-Category Causes

— Focal consolidation on CXR, productive purulent sputum, elevated procalcitonin

— Treat with β-lactam + macrolide or respiratory fluoroquinolone per IDSA/ATS

— Can occur after RSV as superinfection

— Increased dyspnea, sputum volume/purulence

— Treat with bronchodilators, systemic steroids, antibiotics if Anthonisen criteria met

— Always test for viral trigger — RSV/flu/COVID frequently underlie

— Orthopnea, PND, JVD, S3, BNP markedly elevated, pulmonary edema on CXR

— Diurese; viral illness can precipitate — co-existence common

— Pleuritic chest pain, tachycardia, hypoxemia without infiltrate

— D-dimer, CTPA — don't miss in elderly with sudden hypoxemia

— Younger patient, prior asthma history, peak flow reduction

— Albuterol, ipratropium, systemic steroids; viral trigger common

— Dependent lobe infiltrates, dysphagia history, stroke or dementia

— Cover anaerobes if necrotizing; mostly supportive for pneumonitis

— Smoker with persistent symptoms, weight loss, hemoptysis

— CT chest, bronchoscopy

— Acute eosinophilic pneumonia, hypersensitivity pneumonitis, drug-induced (amiodarone, methotrexate)

Bacterial community-acquired pneumonia (CAP):

COPD exacerbation (non-viral):

Acute decompensated heart failure:

Pulmonary embolism:

Asthma exacerbation:

Aspiration pneumonia/pneumonitis:

Lung cancer with post-obstructive pneumonia:

Non-infectious mimickers:

Key distinction: RSV LRTI and CHF frequently coexist in the elderly. Do not pick one; treat both — diuresis plus respiratory support plus antiviral panel.

Step 3 management: Order BNP, troponin, procalcitonin, viral PCR, and CXR together in the elderly winter dyspnea workup — this single bundle answers most diagnostic questions efficiently.

Secondary Prevention, Discharge Planning, and Long-Term Vaccine Strategy

— Vaccinate at discharge if not previously vaccinated and eligible (one-time RSV vaccine)

— Update influenza, COVID-19, pneumococcal (PCV20 or PCV15+PPSV23), and shingles status

— Smoking cessation counseling — RSV severity correlates with smoking

— Review inhaler technique, COPD/asthma controller adequacy

— Optimize HF therapy if applicable (GDMT: ARNI/ACEi, β-blocker, MRA, SGLT2i)

— Identify RSV vaccine eligibility annually during pre-season (August–October)

— Confirm one-time dosing status — do not re-administer unless future ACIP guidance changes

— Document shared decision-making for 50–59 high-risk group

— Confirm infant RSV protection strategy: maternal vaccine effective if given ≥14 days pre-delivery in season; otherwise arrange nirsevimab

— Continue routine postpartum care; RSV vaccine does not contraindicate breastfeeding

— Hand hygiene, avoid sick contacts, mask in high-risk seasons

— Smoke-free home for infants (reduces RSV severity)

— Daycare exposure counseling

— Document in state immunization registry (IIS)

— Provide written record to patient — supports portability when seeing multiple providers

— Medicare Part D covers adult RSV vaccine with $0 cost-sharing

— Commercial insurance covers under ACA preventive services (ACIP-recommended)

— Medicaid coverage varies by state

— Pregnancy: covered under maternity benefits

For the patient hospitalized with RSV:

For the ambulatory preventive visit:

For the postpartum patient:

Household and environmental measures:

Vaccine record-keeping:

Cost and access:

Board pearl: One-time vaccine for adults. If a 76-year-old who got Arexvy two years ago asks about "RSV booster" — the answer is currently no revaccination recommended.

Step 3 management: Use hospital discharge as a vaccination opportunity — Joint Commission and CMS metrics reward this.

Follow-Up, Monitoring, and Counseling

— Phone or in-person check 1–2 weeks post-discharge for symptom resolution, medication reconciliation

— Pulmonary function reassessment in 4–6 weeks if persistent symptoms (COPD/asthma)

— Cardiology follow-up if new AF or troponin elevation during admission

— Pulmonary rehab referral for deconditioned COPD patients

— Expect cough to persist up to 4 weeks — reassure but evaluate if worsening

— Observe 15 minutes post-injection (30 minutes if prior anaphylaxis history)

— Counsel on injection-site reactions, expected mild systemic symptoms 1–3 days

— Advise return for: severe headache, weakness/numbness (GBS concern), persistent fever, allergic reaction

— Report adverse events to VAERS (vaers.hhs.gov)

— Routine prenatal visits continue per schedule

— Document vaccine in prenatal record and infant chart at delivery

— Pediatrician confirms maternal vaccination status at newborn visit to determine nirsevimab need

— Vaccine reduces severe LRTI and hospitalization, not all infection

— Encourage continued hygiene, masking in high-risk settings

— One-time dose currently; revaccination guidance may evolve — recheck at annual visits

— Address vaccine hesitancy with transparent risk/benefit (GBS rare; benefit substantial)

— Track RSV vaccination rates in panel; identify gaps in 75+ and high-risk 50–74

— Use EHR clinical decision support and pre-visit planning

— Standing orders empower MA/RN-driven vaccination

Post-RSV illness follow-up (adult):

Post-vaccination monitoring:

Pregnancy post-vaccination:

Counseling content (ambulatory):

Population health metrics:

Step 3 management: A 67-year-old with COPD asks if they need an RSV vaccine "every year like flu." Answer: No — one-time dose currently; we'll revisit if guidance changes. You still need annual flu and updated COVID-19 vaccines.

Board pearl: Cough lingering 3–4 weeks after RSV is expected post-viral bronchial hyperreactivity — not failed treatment.

Ethical, Legal, and Patient Safety Considerations

— Provide Vaccine Information Statement (VIS) before administration (federal NCVIA requirement for some vaccines; CDC provides VIS for RSV)

— Disclose: benefit (reduced severe LRTI/hospitalization), common reactogenicity, rare GBS signal, atrial fibrillation signal, anaphylaxis risk

— Document shared decision-making, especially in the 50–59 high-risk and 60–74 risk-based groups

— Discuss preterm birth signal context, rationale for 32–36 week window, alternative of infant nirsevimab

— Respect autonomy: patient may decline maternal vaccine and choose nirsevimab for infant

— Both options are acceptable — Step 3 tests non-coercive counseling

— Required for clinically significant adverse events

— Patients can self-report; clinicians should facilitate

— RSV vaccines are not currently covered under the National Vaccine Injury Compensation Program (VICP) for adults; Countermeasures Injury Compensation Program (CICP) may apply during emergencies — know the distinction

— Document vaccination status in discharge summary

— Communicate to PCP and (for postpartum) to pediatrician — missed maternal vaccine documentation can lead to redundant nirsevimab or unprotected infant

— Reconcile vaccine record at every transition

— Rural and minority elderly have lower RSV vaccination uptake — address access (mobile clinics, pharmacy administration)

— Pharmacist-administered vaccines under state scope-of-practice laws improve access

— Frail or cognitively impaired adults — use surrogate decision-maker if lacking capacity; document

— Long-term care: facility consent processes per state law

— Outbreaks in long-term care facilities reportable to local/state health department

Informed consent for adult RSV vaccination:

Pregnancy consent:

VAERS reporting:

Vaccine Injury Compensation:

Transitions of care safety:

Equity considerations:

Decisional capacity in elderly:

Mandatory reporting:

Step 3 management: A 78-year-old with mild cognitive impairment is brought by daughter (DPOA) for vaccination — confirm capacity assessment; if patient assents and surrogate consents, proceed. Document both.

Board pearl: Refusing the vaccine is the patient's right — document the discussion and re-offer at next visit. Coercion is never appropriate.

High-Yield Associations and Rapid-Fire Clinical Facts

RSV is a paramyxovirus (single-stranded negative-sense RNA), genera Orthopneumovirus.

Seasonality: November–March in continental US; year-round in tropical climates and Florida.

Adult RSV burden: ~60K–160K hospitalizations, 6K–10K deaths/year in US ≥65.

Three approved adult RSV vaccines: Arexvy (GSK, adjuvanted), Abrysvo (Pfizer, bivalent), mResvia (Moderna, mRNA).

Only Abrysvo is approved in pregnancy (32 0/7–36 6/7 weeks).

Nirsevimab (Beyfortus) — long-acting monoclonal Ab; passive immunization for infants.

Palivizumab — older monthly monoclonal; now mostly replaced by nirsevimab for routine prophylaxis.

ACIP: ≥75 universal; 50–74 with risk factors.

Single lifetime dose currently — no annual revaccination.

Co-administration with flu, COVID, pneumococcal, Tdap, shingles permitted.

GBS signal: ~1–9 cases per million doses — disclose, don't withhold.

Preterm birth signal led to 32-week minimum gestation for Abrysvo.

Prefusion F protein antigen is the breakthrough — earlier postfusion F vaccines failed (and the 1960s formalin-inactivated RSV vaccine caused enhanced disease in infants, halting pediatric vaccine development for decades).

RSV PCR > antigen test in adults (low antigen sensitivity).

No specific antiviral for adults; ribavirin reserved for select immunocompromised.

Bronchiolitis treatment in infants: supportive only (no routine bronchodilators, steroids, or antibiotics).

~25% of hospitalized RSV adults have an acute cardiac event.

RSV more likely than flu to cause wheeze in elderly.

Vaccine covered by Medicare Part D at $0 (IRA provision).

Long-term care outbreaks: report to public health.

Board pearl: "Prefusion F" is the magic phrase that links Arexvy, Abrysvo, mResvia, and nirsevimab — all target the same conformation.

Key distinction: Maternal vaccine OR infant nirsevimab — not both routinely.

Board Question Stem Patterns

— 76-year-old with COPD presents in September for annual wellness. Vaccines up to date except RSV. Answer: Administer single dose RSV vaccine (Arexvy, Abrysvo, or mResvia); no revaccination planned.

— 30-week pregnant patient in October asks about RSV vaccine. Answer: Wait until 32 weeks; administer Abrysvo at 32 0/7–36 6/7 weeks. Do not give Arexvy.

— Mother received Abrysvo at 34 weeks, delivered at 38 weeks in December. Does the newborn need nirsevimab? Answer: No — maternal antibodies sufficient.

— Mother declined RSV vaccine; baby born in November. Answer: Give nirsevimab to infant before discharge or at first well-child visit.

— 68-year-old wants flu, COVID-19, and RSV vaccines same visit. Answer: All three may be administered concurrently at separate sites.

— 72-year-old develops ascending weakness 2 weeks after RSV vaccine. Answer: Evaluate for GBS (LP, NCS/EMG, neurology consult), supportive care, IVIG or plasmapheresis if confirmed; report to VAERS.

— 80-year-old with PCR-confirmed RSV, SpO2 90%, wheezing. Answer: Droplet/contact precautions, supplemental O2, bronchodilators if responsive, no routine antibiotics, no oseltamivir, supportive care; vaccinate at discharge if not previously.

— Patient declines RSV vaccine citing GBS concern. Answer: Respect autonomy, document discussion, provide accurate risk data, re-offer at next visit.

— Multiple residents with febrile cough, RSV PCR positive. Answer: Cohort/isolate, droplet precautions, report to public health, restrict communal activities, ensure staff masking.

Stem 1 — Older adult preventive visit:

Stem 2 — Pregnancy timing:

Stem 3 — Maternal vs. nirsevimab:

Stem 4 — Co-administration:

Stem 5 — Adverse event:

Stem 6 — Hospitalized RSV management:

Stem 7 — Vaccine refusal:

Stem 8 — Long-term care outbreak:

Step 3 management: Recognize stems that test allocation logic (who gets which vaccine, when) — the most common RSV question type on the exam.

Board pearl: If the stem mentions an unvaccinated mother and a newborn in RSV season → nirsevimab to the infant is the answer.

One-Line Recap

RSV is a vaccine-preventable cause of severe winter respiratory illness in older adults and infants, where a single-dose adult vaccine (Arexvy, Abrysvo, or mResvia) is recommended for everyone ≥75 and high-risk 50–74, and maternal Abrysvo at 32–36 weeks gestation (or infant nirsevimab) protects newborns through their first RSV season.

Adults ≥75: universal one-time RSV vaccine; 50–74 with risk factors (COPD, CHF, CKD, DM, immunocompromise, LTC residence, BMI ≥40): one-time RSV vaccine — any of three products; no annual revaccination currently.

Pregnancy 32 0/7–36 6/7 weeks during September–January: Abrysvo (RSVpreF) only — the 32-week threshold mitigates the preterm birth signal; alternative is infant nirsevimab if mother unvaccinated, vaccinated <14 days pre-delivery, or other risk factors.

No specific antiviral for adult RSV — management is supportive (O2, bronchodilators if responsive, treat comorbidity exacerbations); avoid reflexive antibiotics or oseltamivir; ~25% of hospitalized older adults have a concurrent cardiac event, so check troponin/ECG.

Counseling pearls: disclose rare GBS signal (~1–9/million) during shared decision-making, co-administer with flu/COVID/pneumococcal/shingles/Tdap as needed, document in immunization registry, and use every clinical encounter — annual wellness, hospital discharge, prenatal visit — as a vaccination opportunity covered $0 under Medicare Part D.

Board pearl: When in doubt on Step 3, the RSV answer is usually "administer the single-dose vaccine now" for eligible adults, "Abrysvo at 32–36 weeks" for pregnancy, and "supportive care" for active infection.