Respiratory

COVID-19: outpatient management and antiviral indications

Clinical Overview and When to Suspect COVID-19

— Acute onset (within 10 days) of fever, cough, sore throat, rhinorrhea, myalgias, fatigue, headache, anosmia/ageusia, or GI symptoms (nausea, diarrhea)

— Known close contact (>15 min cumulative within 6 ft over 24 h) with a confirmed case in the prior 10 days

— Cluster illness in household, workplace, congregate setting (nursing home, shelter, dormitory)

— Atypical presentations: isolated fatigue or "off baseline" in elderly, decompensation of underlying cardiopulmonary disease, new delirium

— Age ≥50 (risk rises sharply ≥65)

— Immunocompromise (solid organ transplant, active chemo, B-cell depletion, HIV with CD4 <200, high-dose steroids)

— Pregnancy and recent pregnancy (≤6 weeks postpartum)

— Obesity (BMI ≥30), diabetes, CKD, cardiovascular disease, COPD/asthma, cirrhosis, sickle cell, cancer, dementia

— Unvaccinated or not up-to-date on boosters

SARS-CoV-2 remains an endemic respiratory pathogen with seasonal surges (late fall/winter peaks, plus summer waves driven by Omicron sublineages). Outpatient family medicine encounters dominate the current care landscape.

When to suspect in the ambulatory setting:

Risk-factor screen at every visit for symptomatic patients — this drives the antiviral decision:

Step 3 management: The pivotal outpatient decision is not "do they have COVID" but "are they eligible for antivirals AND within the treatment window (≤5 days of symptom onset for nirmatrelvir-ritonavir; ≤7 days for remdesivir)." Build this into every telehealth or in-person triage script.

Board pearl: Anosmia/ageusia has become less specific with Omicron-era variants but, when present in an unvaccinated adult, still raises pretest probability substantially. Do not rely on classic symptom clusters alone — test liberally in high-risk patients to preserve the antiviral window.

Presentation Patterns and Key History

— Upper respiratory: sore throat, rhinorrhea, nasal congestion, hoarseness — now more prominent than lower-tract disease

— Constitutional: fatigue, myalgia, fever, chills, headache

— Lower respiratory: cough (often dry), dyspnea, pleuritic chest pain

— GI: nausea, vomiting, diarrhea (more common in children)

— Neurologic: anosmia/ageusia (declining incidence), brain fog, dizziness

— Dyspnea at rest or with minimal exertion

— Chest pain, syncope, confusion

— Symptoms worsening after initial improvement (biphasic course) — concerning for inflammatory phase

— Inability to maintain hydration

— Persistent fever beyond 5 days

— Exact symptom onset date (anchors antiviral window)

— Vaccination status and date of last dose/booster

— Prior COVID infections and dates

— Current meds — critical for nirmatrelvir-ritonavir drug interactions (statins, calcineurin inhibitors, amiodarone, rivaroxaban/apixaban, certain anticonvulsants, ergots, sildenafil for PAH)

— Pregnancy/lactation status

— Renal and hepatic function history

— Exposure source for contact tracing and household management

Typical symptom timeline: incubation 2–5 days (range 1–14); symptom peak days 3–5; clinical deterioration, if it occurs, typically days 5–10 (the "inflammatory phase").

Common symptom clusters (Omicron era, in rough order of frequency):

Red-flag history prompting in-person eval and pulse-ox:

Key history points to capture:

CCS pearl: Document "day of illness" on every encounter. A patient on day 4 still qualifies for Paxlovid; on day 6 you've lost the window and pivot to supportive care or remdesivir (if eligible and infusion available).

Key distinction: Influenza and RSV produce overlapping syndromes — order a multiplex respiratory PCR when result will change therapy (oseltamivir vs. nirmatrelvir-ritonavir) and during co-circulation seasons.

Physical Exam Findings and Hemodynamic Assessment

— Temperature, HR, BP, RR, SpO2 on room air at rest AND with ambulation (a 6-minute walk or even hallway walk)

— Resting SpO2 <94% (or drop ≥3% with exertion) signals hypoxia and warrants escalation

— Work of breathing — accessory muscle use, nasal flaring, pursed-lip breathing, tripoding

— Ability to speak in full sentences

— Mental status — new confusion in elderly is a deterioration marker

— Pharyngeal erythema, mild lymphadenopathy common

— Tympanic membranes (otitis more often in children)

— Often deceptively normal auscultation despite hypoxia ("silent hypoxia")

— Crackles, especially bibasilar, suggest pneumonitis

— Wheezing if underlying asthma/COPD exacerbation

— Tachycardia disproportionate to fever — consider myocarditis, PE, dehydration

— Assess for volume status (mucous membranes, cap refill, JVP)

— Unilateral leg swelling → DVT workup (COVID is prothrombotic)

— Cyanosis, mottling = late finding

Vital signs are the cornerstone of outpatient COVID triage. Obtain on every symptomatic visit:

General appearance:

HEENT:

Pulmonary:

Cardiovascular:

Extremities:

Step 3 management: Send patients home with a pulse oximeter if available; instruct to check resting + ambulatory SpO2 twice daily and call if <94%, RR >24, or symptoms worsen after day 5. This home monitoring program is a documented Step 3-style intervention reducing ED utilization.

Board pearl: A normal lung exam does NOT rule out significant COVID pneumonia. Always check ambulatory pulse oximetry in symptomatic high-risk patients — exertional desaturation is the earliest objective sign of pneumonitis and changes management from "supportive care at home" to "escalate, image, and consider hospitalization or monoclonal/antiviral plus close follow-up."

Diagnostic Workup — Initial Testing

— NAAT/PCR (nasopharyngeal or anterior nasal): gold standard, sensitivity >95%, results typically 1–24 h. Preferred when antiviral eligibility hinges on result.

— Rapid antigen test (RAT): sensitivity 60–80% during symptomatic phase; specificity >98%. Single negative RAT in a symptomatic patient does NOT rule out infection — repeat at 48 h, or confirm with NAAT.

— At-home antigen tests are acceptable for treatment decisions per current CDC/IDSA guidance if positive; if negative and clinical suspicion remains, repeat or escalate to PCR.

— Symptomatic + high-risk for severe disease → test immediately (preferably same-day NAAT or in-office RAT) to preserve antiviral window

— Symptomatic + low-risk → home antigen acceptable; encourage isolation while awaiting

— Asymptomatic post-exposure → test at day 5 (RAT × 2 spaced 48 h ideal)

— BMP before nirmatrelvir-ritonavir to confirm eGFR (dose adjust 30–60; avoid <30 unless renal-dosed)

— LFTs if hepatic disease suspected (avoid nirmatrelvir-ritonavir in severe hepatic impairment, Child-Pugh C)

— CBC, CRP, D-dimer only if moderate disease or considering escalation

— Troponin, BNP, ECG if chest pain, dyspnea out of proportion, palpitations

— Chest X-ray NOT routine for mild outpatient illness

— Order CXR if hypoxia, persistent fever >5 days, focal exam findings, or considering bacterial superinfection

— CT chest reserved for suspected PE, atypical course, or pre-existing structural lung disease

Confirmatory testing — choose based on clinical urgency and access:

Testing algorithm in outpatient practice:

Baseline labs — generally NOT needed for uncomplicated outpatient COVID. Order selectively:

Imaging:

Board pearl: eGFR before Paxlovid is the single lab most commonly missed in board questions — the test stem will plant a CKD clue (diabetes ×15 years, baseline creatinine 1.6) expecting you to dose-reduce or substitute.

Diagnostic Workup — Advanced and Confirmatory Studies

— Patient meets criteria for moderate disease (SpO2 90–94%, RR 20–24, infiltrates on imaging)

— Atypical course: prolonged fever >5 days, biphasic deterioration, focal lung findings

— Concern for complication: PE, myocarditis, bacterial superinfection

— CBC with differential — lymphopenia is characteristic; rising WBC with left shift suggests bacterial superinfection

— CRP, ferritin, LDH, D-dimer — elevated values correlate with severity; trending guides escalation

— Procalcitonin — useful in distinguishing bacterial pneumonia (typically elevated) from viral COVID alone (typically normal/low)

— Troponin, NT-proBNP, ECG if cardiac symptoms — myocarditis incidence ~1–2% in symptomatic COVID

— Coagulation panel and D-dimer — markedly elevated D-dimer (>3× upper limit) → image for PE

— CXR: bilateral peripheral patchy opacities classic; lower-zone predominance

— CT chest: ground-glass opacities with peripheral, bilateral, multilobar distribution; "crazy-paving" pattern in progressive disease

— CT pulmonary angiogram if D-dimer markedly elevated, pleuritic chest pain, unexplained hypoxia, or hemodynamic instability

— Lung POCUS — B-lines, subpleural consolidations correlate with CT findings; useful in resource-limited settings

— Targeted to symptoms: PFTs and CT for dyspnea; orthostatics, tilt for POTS; echo if cardiac symptoms; cognitive testing for brain fog; no panel of "long COVID labs" is validated

When to extend the workup beyond a positive test and basic vitals:

Advanced labs in moderate outpatient disease:

Imaging in moderate disease:

Outpatient point-of-care tools increasingly used:

Long COVID / post-acute workup (symptoms persisting >12 weeks):

Key distinction: A positive antigen test 8 days after symptom onset in a previously confirmed case usually represents residual viral antigen, not active transmission — do NOT retest patients to "clear" them. Isolation duration is symptom-based per CDC: end isolation when fever-free 24 h without antipyretics AND symptoms improving (currently aligned with general respiratory virus guidance).

Risk Stratification and First-Line Management Logic

— Mild: symptoms without dyspnea, normal SpO2 — most outpatients

— Moderate: lower respiratory disease (clinical or imaging) with SpO2 ≥94%

— Severe: SpO2 <94%, RR >30, PaO2/FiO2 <300, or >50% lung involvement

— Critical: respiratory failure, shock, multi-organ dysfunction

— Step 1: Confirm diagnosis (test positive or strong clinical suspicion in symptomatic contact)

— Step 2: Establish symptom onset date — must be within 5 days for nirmatrelvir-ritonavir

— Step 3: Assess severe-disease risk factors (age ≥50, immunocompromise, pregnancy, obesity, DM, CKD, CVD, COPD, etc.)

— Step 4: Check eligibility for antiviral — eGFR, hepatic function, drug interactions, pregnancy

— Step 5: Prescribe antiviral + supportive care + return precautions + isolation guidance

— Any patient with mild-to-moderate COVID + ≥1 risk factor for severe disease who is within the treatment window

— Vaccination status does NOT exclude — vaccinated high-risk patients still benefit, especially elderly and immunocompromised

— Low-risk, young, healthy, vaccinated patients with mild symptoms — supportive care alone (acetaminophen, fluids, rest)

— Asymptomatic infection — no antiviral indication

— Hydration, antipyretics (acetaminophen first-line), rest

— Cough suppressants (dextromethorphan) PRN; honey for cough in adults

— Isolation per CDC (mask, separate from household, stay home until fever-free 24 h and symptoms improving)

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

Severity classification (NIH framework):

Outpatient management decision tree — apply within minutes of confirming infection:

Who gets antivirals (current NIH/IDSA guidance):

Who does NOT need antivirals:

Supportive care for all outpatients:

Step 3 management: Build a standing telehealth pathway — patient tests positive at home, calls clinic, nurse triages risk factors and symptoms, MD does brief video visit, e-prescribes Paxlovid same day. Time-to-treatment <72 h from symptom onset maximizes efficacy.

Pharmacotherapy — First-Line Antiviral Regimens

— Dose: 300 mg nirmatrelvir + 100 mg ritonavir PO BID × 5 days

— Window: start within 5 days of symptom onset

— Renal dosing: eGFR 30–60 → 150/100 mg BID; eGFR <30 → not recommended (use alternative)

— Hepatic: avoid in severe impairment (Child-Pugh C)

— NNT ~36 in unvaccinated high-risk; benefit smaller but present in vaccinated high-risk patients

— Absolute contraindications: alfuzosin, ranolazine, eplerenone (some), amiodarone, dronedarone, flecainide, propafenone, simvastatin/lovastatin, rivaroxaban, ergot derivatives, sildenafil for PAH, certain anticonvulsants (carbamazepine, phenytoin, phenobarbital), rifampin, St. John's wort, colchicine in renal/hepatic impairment

— Manage with hold/dose adjustment: atorvastatin/rosuvastatin (hold), apixaban (reduce or switch), tacrolimus/cyclosporine (specialist input, dose dramatically reduced), amlodipine (monitor), inhaled/intranasal fluticasone (switch to beclomethasone — Cushing risk)

— Always run a Liverpool COVID drug interaction check before prescribing

— Dose: 200 mg IV day 1, then 100 mg IV days 2–3 (3-day outpatient course)

— Window: within 7 days of symptom onset

— Requires infusion center access; logistical barrier

— Preferred when severe renal impairment, severe DDIs, pregnancy considerations

Nirmatrelvir-ritonavir (Paxlovid) — preferred first-line outpatient antiviral

Critical drug interactions (ritonavir is a potent CYP3A4 inhibitor):

Common adverse effects: dysgeusia ("Paxlovid mouth" — metallic taste, ~6%), diarrhea, nausea, hypertension, myalgia. Rebound (symptom or test-positive recurrence) occurs in ~10–20% but is generally mild and self-limited; current guidance does NOT recommend retreatment.

Remdesivir IV — alternative when Paxlovid contraindicated

Molnupiravir — last-line, lower efficacy (~30% relative reduction), avoid in pregnancy and reproductive-age patients without contraception; reserved when Paxlovid and remdesivir both unavailable.

Board pearl: A transplant patient on tacrolimus + new COVID = do NOT just prescribe Paxlovid. Call transplant pharmacy — tacrolimus must be held and trough monitored, or choose remdesivir instead.

Adjunctive Therapy and What NOT to Prescribe Outpatient

— Dexamethasone is NOT recommended for non-hypoxemic outpatients — may worsen outcomes in mild disease

— Reserve systemic steroids for SpO2 <94% on room air (typically inpatient threshold)

— Continue baseline inhaled corticosteroids for asthma/COPD — do not stop

— Treat asthma/COPD exacerbations per usual guidelines (oral steroids if indicated by the obstructive disease, not by COVID alone)

— Outpatient prophylactic anticoagulation NOT routinely recommended

— Consider in select high-risk patients (prior VTE, active cancer, recent surgery) — individualize

— Aspirin not recommended for COVID-specific indication

— NOT routine — bacterial co-infection in outpatient COVID is uncommon (<5%)

— Reserve for documented or strongly suspected bacterial superinfection (procalcitonin elevation, focal consolidation, purulent sputum, leukocytosis with left shift)

— Most prior monoclonals (bamlanivimab, casirivimab/imdevimab, bebtelovimab, sotrovimab) are no longer authorized due to variant resistance

— Check current FDA EUA list at time of prescribing — landscape changes

— Pemivibart (long-acting prophylactic mAb) available for pre-exposure prophylaxis in severely immunocompromised

— Ivermectin, hydroxychloroquine, azithromycin as COVID-specific therapy — multiple RCTs negative, harms documented

— Vitamin/zinc megadoses — no clear benefit; high-dose zinc causes copper deficiency

— Nebulized treatments in clinic settings without proper PPE (aerosolization risk)

— Acetaminophen preferred antipyretic; NSAIDs acceptable (early concerns unfounded)

— Prone positioning if hypoxic awaiting transfer — increases oxygenation

— Smoking cessation counseling — acute teachable moment

Inhaled/systemic corticosteroids — outpatient nuance:

Anticoagulation:

Antibiotics:

Monoclonal antibodies:

Therapies to explicitly avoid / counsel against:

Symptomatic management pearls:

Step 3 management: When a patient asks about ivermectin, document the patient-centered discussion, share evidence summary, address underlying concerns (fear, distrust), and offer evidence-based alternatives. This patient-communication competency is testable on Step 3.

Special Populations — Elderly and Renal/Hepatic Impairment

— Highest absolute risk of severe disease and death

— Atypical presentations: delirium, falls, decompensation of CHF/COPD, anorexia — fever may be absent

— Antivirals strongly indicated even if symptoms appear mild

— Polypharmacy → meticulous drug interaction screen before Paxlovid

— Common offenders in geriatric med lists: statins, amiodarone, apixaban/rivaroxaban, amlodipine, donepezil, quetiapine, tamsulosin

— Lower threshold for in-person evaluation, home pulse oximeter, daily nurse phone check

— Vaccination/boosters every 6 months per current ACIP for ≥65

— eGFR ≥60: standard Paxlovid 300/100 mg BID

— eGFR 30 to <60: reduced dose 150/100 mg BID × 5 days

— eGFR <30 (including dialysis): Paxlovid NOT recommended; use remdesivir (safe in CKD/ESRD per recent data despite original label) or molnupiravir

— Acute kidney injury during illness — recheck eGFR before continuing

— Mild-moderate (Child-Pugh A/B): no dose adjustment

— Severe (Child-Pugh C): avoid Paxlovid; use remdesivir with LFT monitoring

— Remdesivir: monitor ALT; discontinue if ALT >10× ULN or with signs of hepatic dysfunction

— Outbreak management: test symptomatic + exposed, cohort positives, restrict visitors per facility policy

— Treat eligible residents within hours of positive test — facility pharmacy stock matters

— Update advance directives early in illness

Elderly (≥65, especially ≥75):

Renal impairment:

Hepatic impairment:

Nursing home / long-term care residents:

Board pearl: An 82-year-old with mild URI symptoms, baseline Cr 1.4 (eGFR ~45), on apixaban for AFib tests positive on day 2. Correct answer: Paxlovid 150/100 mg BID × 5 days AND hold or reduce apixaban per cardiology guidance (or substitute remdesivir if anticoagulation management is unsafe to alter). Don't pick "supportive care alone" — high-risk geriatric patients benefit substantially from antivirals.

Special Populations — Pregnancy, Pediatrics, Immunocompromised

— Pregnancy is an independent risk factor for severe COVID — ICU admission, mechanical ventilation, preterm birth, stillbirth

— Nirmatrelvir-ritonavir is recommended during pregnancy per SMFM/ACOG/NIH — benefits outweigh theoretical risks; observational data reassuring

— Remdesivir acceptable alternative — extensive pregnancy safety data

— Molnupiravir contraindicated in pregnancy (embryofetal toxicity in animals); avoid in reproductive-age patients not using contraception

— Vaccination/boosters strongly recommended at any gestational age — protects mother and confers passive immunity to neonate

— Monitor for preterm labor, preeclampsia (overlapping symptoms)

— Paxlovid and remdesivir considered compatible with breastfeeding

— Continue breastfeeding through illness with masking and hand hygiene

— Generally milder disease; severe disease in infants <6 months, immunocompromised, complex chronic conditions

— Paxlovid authorized for ≥12 years AND ≥40 kg at adult dose

— Remdesivir authorized for ≥28 days old and ≥3 kg

— Watch for MIS-C (multisystem inflammatory syndrome in children) 2–6 weeks post-infection: fever, rash, conjunctivitis, GI symptoms, cardiac dysfunction — refer to ED

— Vaccination recommended ≥6 months per ACIP

— Highest priority for antiviral treatment — even mild symptoms

— Prolonged viral shedding common — extended isolation if persistently symptomatic

— Pemivibart for pre-exposure prophylaxis when authorized

— Consider longer antiviral courses in consultation with ID for severely immunocompromised (off-label, evolving evidence)

— Updated booster schedule: additional doses per ACIP for moderately/severely immunocompromised

Pregnancy and postpartum (≤6 weeks):

Lactation:

Pediatrics:

Immunocompromised (transplant, active chemo, B-cell depletion, advanced HIV):

Key distinction: A pregnant patient with mild COVID is high-risk by virtue of pregnancy alone — she qualifies for Paxlovid regardless of age, BMI, or comorbidities. Don't withhold therapy due to outdated pregnancy-category thinking.

Complications and Adverse Outcomes

— Viral pneumonitis → ARDS (the classic severe-disease pathway)

— Bacterial superinfection (S. pneumoniae, S. aureus including MRSA) — typically week 2+

— Secondary fungal infections (aspergillosis, mucormycosis) — immunocompromised, post-steroid

— COVID is prothrombotic — DVT, PE, arterial thrombosis (stroke, MI, limb ischemia)

— Risk highest in hospitalized; persists weeks after acute illness

— Low threshold for D-dimer, imaging if suggestive symptoms

— Myocarditis — acute and post-acute; chest pain, dyspnea, palpitations, troponin elevation

— Arrhythmias (atrial fibrillation new-onset common)

— Acute coronary events

— Stress cardiomyopathy

— Pericarditis

— Stroke (ischemic and hemorrhagic)

— Encephalopathy, encephalitis

— Guillain-Barré syndrome (rare)

— Persistent anosmia, dysgeusia

— AKI from direct viral injury, hypovolemia, rhabdomyolysis, contrast/medications

— Symptoms persisting >12 weeks not explained by alternative diagnosis

— Common: fatigue, dyspnea, brain fog, palpitations, POTS, insomnia, anxiety/depression, anosmia

— Affects ~5–10% of infections; reduced incidence with vaccination and antiviral treatment

— Multidisciplinary management — no single curative therapy

— Increased depression, anxiety, PTSD during and after illness

— Screen with PHQ-9, GAD-7 at follow-up

— 2–6 weeks post-infection; Kawasaki-like with shock, cardiac dysfunction

— Requires hospitalization, IVIG, steroids — ED referral

Respiratory:

Thromboembolic:

Cardiac:

Neurologic:

Renal:

Long COVID / post-acute sequelae (PASC):

Mental health:

Pediatric MIS-C:

Step 3 management: At every post-COVID follow-up, screen explicitly for (1) persistent dyspnea/exertional intolerance, (2) chest pain/palpitations, (3) cognitive symptoms, (4) mood symptoms. Refer to long-COVID clinic or relevant specialist (pulm, cards, neuro, psych) based on dominant symptom domain. Antiviral treatment during acute illness has been associated with reduced PASC incidence — another reason to treat aggressively.

When to Escalate Care — ED Referral and Hospitalization

— SpO2 <90% on room air or significant exertional desaturation (<88%)

— Severe dyspnea, accessory muscle use, inability to speak in full sentences

— Altered mental status, syncope, new focal neurologic deficit

— Chest pain with concern for ACS, PE, or myocarditis

— Hemodynamic instability — SBP <90, HR >130, signs of shock

— Inability to tolerate PO, signs of dehydration

— Cyanosis

— SpO2 90–93% on room air

— RR >24 sustained

— Persistent fever >5 days or biphasic worsening

— Comorbid decompensation (CHF, COPD exacerbation, hyperglycemia in DM)

— Pregnant patient with any concerning symptom

— Severely immunocompromised with progressive symptoms

— SpO2 <94% on room air requiring supplemental O2

— Pneumonia with hypoxia or significant infiltrate burden

— Inability to maintain hydration/nutrition

— Concomitant condition requiring inpatient care

— Social factors precluding safe home isolation (homelessness, vulnerable household contacts without separation possible)

— Supplemental oxygen, dexamethasone 6 mg daily × up to 10 days (for hypoxia)

— Remdesivir IV (5-day course inpatient)

— Baricitinib or tocilizumab for severe disease with elevated inflammatory markers

— Prophylactic anticoagulation (inpatient standard)

Immediate ED referral indications (call EMS for severe distress):

Consider in-person evaluation or ED (intermediate concerns):

Hospitalization criteria (set by ED/admitting team, but you should know):

Inpatient therapies you should recognize (so you set expectations at transfer):

CCS pearl: In a CCS-style case, a patient who initially called for telehealth on day 3 with mild symptoms but on day 7 follow-up has SpO2 88% and RR 26 — your sequence is: "Send to ED" → orders auto-include: IV access, pulse oximetry, CXR, CBC, BMP, troponin, D-dimer, blood cultures, dexamethasone, remdesivir initiation, prophylactic enoxaparin. Do not order outpatient labs; do not "recheck in clinic tomorrow."

Board pearl: Silent hypoxia is real — a comfortable-appearing patient with SpO2 87% still requires emergent evaluation regardless of how well they look.

Key Differentials — Other Respiratory Viruses

— Abrupt onset, high fever, prominent myalgias, headache

— Seasonal (peak Dec–Feb in US)

— Diagnostic: multiplex respiratory PCR or rapid flu antigen/molecular test

— Treatment: oseltamivir 75 mg PO BID × 5 days within 48 h; baloxavir alternative

— Can co-occur with COVID ("flurona") — treat both

— Increasingly recognized in adults, especially elderly and immunocompromised

— Wheezing, lower respiratory symptoms prominent

— No specific antiviral for adults outpatient; supportive

— RSV vaccine available for ≥75, 60–74 with risk factors, pregnancy 32–36 weeks

— Common cold syndrome — rhinorrhea, sore throat dominant

— Self-limited; supportive care only

— Variable presentations; identified on multiplex PCR if pursued

— Generally supportive treatment

— Centor/McIsaac criteria: fever, tonsillar exudates, tender anterior cervical adenopathy, absence of cough, age

— Rapid strep antigen + culture if needed

— Treat with penicillin or amoxicillin

— Paroxysmal cough, post-tussive emesis, inspiratory whoop

— More common in unimmunized; consider in prolonged cough >2 weeks

— Walking pneumonia — gradual onset, persistent dry cough, low-grade fever, often young adults

— Treat with macrolide or doxycycline

— Cough >5 days, often post-URI

— No antibiotics indicated routinely

Influenza A/B:

RSV:

Rhinovirus / other coronaviruses (non-SARS-CoV-2):

Parainfluenza, adenovirus, metapneumovirus:

Bacterial pharyngitis (Group A Strep):

Pertussis:

Mycoplasma pneumoniae:

Acute bronchitis (non-specific viral):

Key distinction: During co-circulation seasons, order multiplex respiratory PCR (flu/RSV/SARS-CoV-2 at minimum) when result will change therapy. A positive flu test in a high-risk patient → oseltamivir within 48 h; a positive COVID test → Paxlovid within 5 days; both positive → both treatments concurrently with attention to drug interactions.

Key Differentials — Non-Infectious and Other-Category Causes

— Pleuritic chest pain, dyspnea, tachycardia, unilateral leg swelling

— May coexist with or mimic COVID

— Wells score → D-dimer or CTPA

— COVID predisposes — keep PE on differential through acute and recovery phases

— Chest pressure, radiation, diaphoresis, exertional onset

— ECG and troponin in any COVID patient with chest pain

— COVID-associated MI documented, especially in elderly with CVD

— Dyspnea, orthopnea, PND, leg edema, JVD

— BNP, CXR, echo

— Can be precipitated by COVID or COVID-induced myocarditis

— Wheezing, increased sputum, prolonged expiration

— Triggered by COVID — treat underlying disease (bronchodilators, oral steroids) in parallel with COVID management

— Productive purulent sputum, focal consolidation, leukocytosis with left shift, elevated procalcitonin

— Empiric treatment if suspected per CAP guidelines

— Itchy eyes, sneezing, clear rhinorrhea without fever

— Antihistamines respond

— History of vaping THC products, bilateral infiltrates, hypoxia

— Diagnosis of exclusion

— Sepsis, transfusion-related, drug-induced

— Diagnosis of exclusion; check SpO2, ECG, basic labs first

Pulmonary embolism:

Acute coronary syndrome:

Congestive heart failure exacerbation:

COPD or asthma exacerbation:

Bacterial pneumonia:

Allergic rhinitis / viral URI overlap:

Vaping-associated lung injury (EVALI):

Pulmonary edema (non-cardiogenic):

Anxiety / hyperventilation:

Step 3 management: A COVID-positive patient with new chest pain — do not anchor on COVID alone. Get ECG, troponin, and consider D-dimer/CTPA. Missing concurrent ACS or PE in a COVID patient is a documented safety event and a favorite Step 3 trap.

Secondary Prevention and Long-Term Plan

— Annual updated COVID vaccine recommended for everyone ≥6 months per current ACIP

— Adults ≥65 and immunocompromised: additional dose 6 months after first annual dose

— Pregnant patients: vaccination at any trimester — provides maternal and neonatal protection

— Document vaccine status at every encounter; offer at point of care

— Pemivibart (long-acting monoclonal) when authorized — every 3 months

— Limited to those unable to mount adequate vaccine response

— No routine post-exposure prophylaxis recommended for general population

— Test at day 5 post-exposure if asymptomatic; immediately if symptomatic

— Mask in public for 10 days post-exposure

— Isolation of cases, ventilation, masking during high transmission

— Vulnerable household members → mask, separate, monitor symptoms

— Smoking cessation — major modifier of severity

— Weight management, glycemic control, BP control — comorbidity optimization

— Influenza vaccine, RSV vaccine (eligible adults), pneumococcal vaccines per ACIP — co-administer when possible

— Resume baseline preventive care

— If hospitalized: consider 3-month follow-up echo if cardiac involvement, PFTs if persistent dyspnea

— Update vaccinations 90 days after acute infection (current guidance) if any vaccine due

— Treating acute COVID with antivirals reduces hospitalization, death, and likely long COVID

— Reinforces importance of testing and treating every eligible patient — population-level prevention through individual treatment

Vaccination — primary prevention pillar:

Pre-exposure prophylaxis (PrEP) for severely immunocompromised:

Post-exposure management:

Household and workplace prevention:

Counseling at every visit:

Patients who recovered from acute COVID:

Antivirals as secondary prevention concept:

Board pearl: A 70-year-old just recovered from mild COVID asks when to get her updated vaccine. Answer: after acute illness resolution; current guidance allows vaccination once symptoms have resolved, though many wait ~3 months from infection for optimal immune response — check current ACIP at time of visit.

Follow-Up, Monitoring, and Rehab/Counseling

— Day 2–3: Nurse phone check or patient portal message — symptom trajectory, adherence to antiviral, side effects

— Day 5–7: Targeted touch-base — peak deterioration window; ask about dyspnea, new fever, chest pain, ambulatory SpO2

— Day 10–14: Confirm resolution, address persistent symptoms, update vaccine plan

— 6–12 weeks: Screen for long COVID if symptoms persist; otherwise resume routine care

— Daily home temperature

— Ambulatory SpO2 twice daily (if pulse oximeter available)

— Symptom diary — new or worsening symptoms trigger contact

— Hydration and PO intake

— Light activity acceptable once afebrile and feeling better

— Avoid strenuous exercise for 1–2 weeks if symptomatic; longer if cardiac symptoms (rule out myocarditis first with ECG/troponin/echo if exertional symptoms)

— Graded return to athletics per pediatric/sports medicine guidance for myocarditis-cleared patients

— Indicated for post-hospitalization with persistent dyspnea/deconditioning

— Structured 6–12 week program

— Pacing strategies for fatigue and brain fog

— CBT, graded activity for long COVID

— Treat comorbid depression/anxiety actively

— Increased salt and fluid intake (2–3 L water, 10 g salt unless contraindicated)

— Compression stockings

— Recumbent → upright exercise reconditioning

— Beta-blockers, ivabradine, midodrine, fludrocortisone if needed

— Stay home until fever-free 24 h without antipyretics AND symptoms improving

— Mask and added precautions for 5 days after returning to normal activity

Follow-up cadence after outpatient COVID diagnosis:

Monitoring parameters during acute illness:

Return-to-activity counseling:

Pulmonary rehabilitation:

Cognitive and mental health rehab:

POTS/dysautonomia management (post-COVID):

Isolation duration counseling (per current CDC respiratory virus guidance):

Step 3 management: Document a structured follow-up plan in the chart at the index visit — telehealth on day 5, in-person if SpO2 <94% or symptoms worsen. Closing the loop is a measurable quality metric and a Step 3 patient-safety theme.

Ethical, Legal, and Patient Safety Considerations

— Discuss benefits (reduced hospitalization, death, possibly long COVID), risks (drug interactions, side effects, rebound), and alternatives (supportive care, remdesivir, no treatment)

— Document the conversation, especially in patients on complex med regimens (transplant, anticoagulation)

— Patient autonomy includes declining treatment — respect after thorough counseling

— Use EHR-integrated drug interaction checkers AND a dedicated COVID resource (Liverpool, IDSA)

— Communicate medication holds to patient verbally AND in written after-visit summary

— Loop in pharmacy — many systems have COVID antiviral pharmacist review

— Closed-loop communication to subspecialists (transplant, cardiology) when holding their medications

— COVID-19 is reportable in all US jurisdictions (laboratory and case-based)

— Outbreaks in congregate settings (LTC, schools, workplaces) — notify public health

— Healthcare worker infections — report per OSHA and facility policy

— Provide isolation documentation per CDC current guidance

— Avoid arbitrary "return to work" testing — not recommended; symptom-based criteria preferred

— Patient discharged from ED on Paxlovid → ensure PCP follow-up scheduled, eGFR confirmed, drug list reconciled

— Hospital discharge after severe COVID → reconcile new anticoagulation, steroid taper, oxygen needs, vaccine plan, pulmonary follow-up

— Failure to reconcile = adverse event

— Address vaccine hesitancy with motivational interviewing, not coercion

— Respect informed refusal; document

— Mandates in specific employment contexts (healthcare, military) — know institutional policy

— Antivirals must be available in underserved areas — Test-to-Treat sites, pharmacist prescribing in some states

— Address language barriers, cost concerns (Paxlovid covered under various assistance programs)

Informed consent for antivirals:

Drug interaction safety — system-level:

Mandatory reporting and public health:

Workplace and school notes:

Transitions of care — high-risk Step 3 theme:

Vaccine counseling ethics:

Equity and access:

Board pearl: A patient on simvastatin is prescribed Paxlovid without instruction to hold the statin — develops rhabdomyolysis. This is a preventable adverse drug event and a textbook Step 3 patient safety scenario. The safeguard: pharmacist review + EHR alert + explicit "hold statin × 8 days" written instruction + patient teach-back.

High-Yield Associations and Rapid-Fire Clinical Facts

Anosmia + ageusia — historically COVID-specific; less sensitive with Omicron but high specificity when present

Lymphopenia + elevated LDH + elevated CRP + elevated D-dimer = classic severe-COVID lab quartet

Bilateral peripheral ground-glass opacities on CT chest — radiologic signature

Paxlovid window = 5 days from symptom onset; remdesivir window = 7 days

Paxlovid dose adjustment: eGFR 30–60 → 150/100 mg BID; eGFR <30 → don't use

Most dangerous Paxlovid interactions: simvastatin, amiodarone, rivaroxaban, tacrolimus, ergots, certain anticonvulsants

Rebound after Paxlovid: ~10–20%, usually mild, no retreatment indicated

Pregnancy is an independent severe-disease risk factor — treat with Paxlovid or remdesivir; avoid molnupiravir

Myocarditis after COVID infection >> after vaccination — risk-benefit favors vaccination

MIS-C = pediatric multisystem inflammatory syndrome, 2–6 weeks post-infection

Silent hypoxia — SpO2 dramatically low with minimal distress; check ambulatory pulse oximetry

Dexamethasone benefit = hypoxic patients only; harm in non-hypoxic outpatient

Bacterial superinfection = uncommon (<5%) — no routine antibiotics

Ivermectin and hydroxychloroquine — no role; counsel against

Annual updated COVID vaccine per ACIP for all ≥6 months; additional doses for ≥65 and immunocompromised

Long COVID affects ~5–10% of infections; reduced by vaccination and antiviral treatment

POTS post-COVID — increased salt/fluid, compression, reconditioning, beta-blocker/ivabradine

D-dimer markedly elevated in COVID + pleuritic pain → image for PE

Procalcitonin helps distinguish bacterial pneumonia from pure viral COVID

CDC isolation = fever-free 24 h without antipyretics + symptoms improving (general respiratory virus guidance)

Test-to-Treat sites enable same-day antiviral access — public health infrastructure

Co-infection with influenza ("flurona") — treat both; check Paxlovid–oseltamivir compatibility (compatible)

Board pearl: The single most common Step 3 trap is failure to prescribe antivirals to eligible patients — vaccinated elderly patients with mild symptoms still qualify and benefit. Treat liberally within the window.

Board Question Stem Patterns

— Answer: Prescribe Paxlovid 300/100 BID × 5 days, hold atorvastatin during and 2 days after course. Not "supportive care only."

— Answer: Paxlovid 150/100 BID × 5 days (reduced dose). If eGFR <30 → remdesivir.

— Answer: Remdesivir OR Paxlovid only with transplant pharmacy coordination and tacrolimus held with trough monitoring. Avoid casual Paxlovid prescribing.

— Answer: Paxlovid (preferred) or remdesivir — pregnancy = independent high-risk indication. NOT molnupiravir. NOT supportive care alone.

— Answer: ED referral for oxygen and inpatient evaluation. Not "outpatient Paxlovid and recheck tomorrow."

— Answer: Past Paxlovid window (5 d); within remdesivir window (7 d) → consider IV remdesivir if infusion access. Otherwise supportive care + close monitoring.

— Answer: No retreatment. Supportive care, isolate per current CDC guidance.

— Answer: Patient-centered discussion of evidence, explore concerns, offer evidence-based options. Document. NOT prescribe ivermectin.

— Answer: No antibiotics. Procalcitonin if uncertain.

— Answer: ECG, troponin, echo — rule out myocarditis before return to play.

Pattern 1 — Antiviral eligibility: "68-year-old vaccinated woman with DM and HTN presents day 3 of cough, sore throat, malaise. Home antigen positive. Vitals normal, SpO2 97%. eGFR 72. Meds: metformin, lisinopril, atorvastatin. Next step?"

Pattern 2 — Renal dose adjustment: "75-year-old with CKD stage 3b (eGFR 38) tests positive day 2."

Pattern 3 — Drug interaction trap: "Transplant patient on tacrolimus with new COVID, day 2 symptoms."

Pattern 4 — Pregnancy: "28-year-old at 24 weeks gestation, mild COVID symptoms day 2."

Pattern 5 — Silent hypoxia: "Comfortable-appearing patient, SpO2 87% on room air."

Pattern 6 — Missed window: "Patient presents day 7 of symptoms, high risk."

Pattern 7 — Rebound: "Patient completed Paxlovid, asymptomatic for 3 days, now retesting positive with mild symptoms."

Pattern 8 — Ivermectin request: "Patient asks for ivermectin."

Pattern 9 — Inappropriate antibiotic: "Mild COVID, no bacterial features."

Pattern 10 — Post-COVID chest pain in athlete: "19-year-old athlete, post-COVID, exertional chest pain."

Step 3 management: When in doubt on a Step 3 stem, the answer that combines specific antiviral + specific dose adjustment + specific drug hold + specific follow-up beats the generic "supportive care."

One-Line Recap

Test every symptomatic high-risk patient promptly, treat eligible patients within the antiviral window (Paxlovid ≤5 days, remdesivir ≤7 days) with attention to renal dose adjustment and CYP3A4 drug interactions, and build structured follow-up to catch the day-5–10 deterioration window.

Antiviral decision: Mild-to-moderate COVID + ≥1 risk factor (age ≥50, immunocompromise, pregnancy, obesity, DM, CKD, CVD, COPD, etc.) + within window = Paxlovid 300/100 BID × 5 days (150/100 BID if eGFR 30–60). Vaccination status does NOT exclude eligibility — vaccinated high-risk patients still benefit.

Drug-interaction discipline: Always run a dedicated COVID drug interaction check before prescribing Paxlovid; hold or substitute statins, watch DOACs, coordinate transplant immunosuppressants, and pick remdesivir when interactions are unmanageable, eGFR <30, or severe hepatic impairment.

Triage and safety: Ambulatory pulse oximetry catches silent hypoxia — SpO2 <94% room air or exertional drop ≥3% triggers escalation; SpO2 <90%, severe dyspnea, chest pain, altered mental status, or hemodynamic instability mean immediate ED referral, not "recheck tomorrow."

Prevention and follow-up loop: Annual updated COVID vaccine for all ≥6 months (additional doses for ≥65 and immunocompromised), structured day 5–7 telehealth check during acute illness, 6–12 week screen for long COVID, and consistent counseling against unproven therapies (ivermectin, hydroxychloroquine) while offering evidence-based alternatives.

Board pearl: The signature Step 3 COVID question rewards the answer that integrates antiviral selection + dose adjustment + drug interaction management + closed-loop follow-up — not the minimalist "supportive care" option that under-treats eligible high-risk patients and not the over-aggressive answer that ignores contraindications.