57.3 Viral Hepatitis B & C: Long-Term Monitoring & DAA Therapy

ABFM Family Medicine Certification Study Guide Exam

Track your progress as you read

Finished sections get a check mark.

1 Chapter 1: Exam Structure, Blueprint & Clinical Decision-Making

1.1 Exam Blueprint, FMCLA vs. One-Day Exam & Board Scoring 1.2 Clinical Reasoning, Test-Taking Strategy & Ambiguity Management 1.3 Evidence-Based Medicine & Clinical Practice Guidelines in Primary Care

2 Chapter 2: Healthcare Systems, Practice Management & Quality

2.1 Practice Management, Billing, Coding & Documentation 2.2 Quality Improvement, Patient Safety & Diagnostic Stewardship 2.3 Interprofessional Team-Based Care & Care Coordination

3 Chapter 3: Ethics, Law, Biostatistics & Health Equity

3.1 Medical Ethics, Informed Consent & Surrogate Decision-Making 3.2 Biostatistics, Clinical Epidemiology & Diagnostic Test Interpretation 3.3 Social Determinants of Health, Health Equity & Cultural Humility 3.4 Physician Wellness, Burnout Prevention & Professionalism

4 Chapter 4: Lifestyle Counseling & Behavior Change

4.1 Alcohol Use Screening & Brief Intervention 4.2 Illicit Drug & Cannabis Counseling 4.3 Tobacco & Vaping Cessation Counseling

5 Chapter 5: Nutrition, Physical Activity & Chronic Disease Prevention

5.1 Dietary Counseling for Obesity & Chronic Disease Prevention 5.2 Exercise Prescription & Physical Activity Counseling 5.3 Genetic Risk Assessment & Family History Counseling

6 Chapter 6: Routine Adult Immunizations

6.1 ACIP Adult Respiratory Vaccines: Influenza, COVID-19, RSV & Pneumococcal 6.2 ACIP Adult Non-Respiratory Vaccines: Tdap, Shingrix, HPV & Hep B 6.3 Immunizations in Special Populations: Pregnancy, Asplenia & Immunocompromise

7 Chapter 7: Pediatric Health Maintenance & Surveillance

7.1 Newborn Examination & Early Postnatal Care 7.2 Well-Child Care, Developmental Surveillance & Milestones 7.3 Pediatric & Adolescent Screening: Vision, Hearing, Anemia & Lead 7.4 Pediatric Oral Health, Dental Screening & Fluoride

8 Chapter 8: Behavioral Health & Safety Screening

8.1 Primary Care Depression, Anxiety & Behavioral Health Screening 8.2 Domestic Violence, Intimate Partner Violence & Firearm Safety 8.3 Occupational Health & Recreational Safety Counseling

9 Chapter 9: Adult Preventive Screening: Cardiovascular & Metabolic

9.1 Cardiovascular Disease & Hypertension Screening 9.2 Type 2 Diabetes Screening & Prediabetes Risk Stratification 9.3 Abdominal Aortic Aneurysm & Osteoporosis Screening

10 Chapter 10: Adult Cancer Screening: Breast & Gynecologic

10.1 Breast Cancer Screening & Risk-Assessment 10.2 Cervical Cancer Screening & ASCCP Algorithms 10.3 Skin Cancer Clinical Assessment & Counseling

11 Chapter 11: Adult Cancer Screening: Colorectal, Lung & Prostate

11.1 Colorectal Cancer Screening Modalities & Intervals 11.2 Lung Cancer Screening with Low-Dose CT 11.3 Prostate Cancer Screening & Shared Decision-Making

12 Chapter 12: Sexual Health, Infectious Disease Screening & Contraception

12.1 Sexual Health Counseling & Risk-Reduction Strategies 12.2 STI Screening: Chlamydia, Gonorrhea, Syphilis & Trichomoniasis 12.3 Bloodborne Infectious Disease Screening: HIV & Hepatitis C

13 Chapter 13: Reproductive Life Planning, Lactation & Preoperative Care

13.1 Preconception Planning & Comprehensive Contraception Management 13.2 Lactation Support & Breastfeeding Counseling 13.3 Preoperative Medical Evaluation & Pre-Participation Sports Exam

14 Chapter 14: Emergent Cardiovascular Conditions

14.1 Acute Coronary Syndromes & Myocardial Infarction 14.2 Acute Chest Pain Risk Stratification & Triage 14.3 Acute or Critical Valvular Heart Emergencies

15 Chapter 15: Cardiac Arrhythmias, Heart Failure & Hypertensive Crises

15.1 Acute Atrial & Ventricular Arrhythmias 15.2 Acute Decompensated Heart Failure & Cardiogenic Shock 15.3 Hypertensive Emergency & Urgency Management

16 Chapter 16: Vascular & Thromboembolic Emergencies

16.1 Pulmonary Embolism & Deep Vein Thrombosis 16.2 Acute Aortic Syndromes & Peripheral Vascular Emergencies 16.3 Critical Limb Ischemia & Acute Arterial Occlusion

17 Chapter 17: Neurologic Emergencies: Stroke & Altered Consciousness

17.1 Acute Ischemic Stroke & Intracranial Hemorrhage 17.2 Syncope Evaluation & Status Epilepticus 17.3 Acute Delirium, Encephalopathy & Severe Confusion

18 Chapter 18: Neurologic Trauma & Acute Cranial Emergencies

18.1 Concussion, Moderate-to-Severe TBI & Intracranial Injury 18.2 Thunderclap & Acute Severe Secondary Headaches 18.3 Acute Ophthalmologic Emergencies

19 Chapter 19: Acute Abdominal, Pelvic & Gastrointestinal Emergencies

19.1 Acute Abdominal & Pelvic Pain Triage 19.2 Upper & Lower Gastrointestinal Bleeding 19.3 Acute Hepatic Failure, Cholangitis & Severe Jaundice

20 Chapter 20: Acute Pulmonary & Airway Emergencies

20.1 Acute Hypoxic Respiratory Failure & ARDS 20.2 Severe Community-Acquired Pneumonia & Empyema 20.3 Acute Severe Epistaxis & Airway Obstruction

21 Chapter 21: Acute Traumatic Injuries & Wound Care

21.1 Major Trauma Resuscitation & Initial Assessment 21.2 Burn Assessment, Inhalation Injury & Resuscitation 21.3 Laceration Management, Complex Wounds & Animal Bites

22 Chapter 22: Acute Orthopedic & Musculoskeletal Emergencies

22.1 Acute Ambulatory Fractures & Initial Splinting 22.2 Compartment Syndrome & Major Orthopedic Trauma 22.3 Septic Arthritis & Acute Microcrystalline Crises

23 Chapter 23: Severe Infections, Sepsis & Systemic Emergencies

23.1 Sepsis, Septic Shock & Initial Fluid Resuscitation 23.2 Necrotizing Soft Tissue Infections & Severe CNS Infections 23.3 Anaphylaxis Diagnosis, Epinephrine Dosing & Airway Protection

24 Chapter 24: Metabolic, Endocrine & Electrolyte Emergencies

24.1 Diabetic Ketoacidosis & Hyperosmolar Hyperglycemic State 24.2 Critical Electrolyte Emergencies: Dyskalemias & Dysnatremias 24.3 Severe Calcium Abnormalities & Acute Adrenal Crisis

25 Chapter 25: Hematologic, Urologic & Dental Emergencies

25.1 Severe Symptomatic Anemias & Coagulopathic Emergencies 25.2 Testicular Torsion, Priapism & Acute Urinary Retention 25.3 Urgent Odontogenic Infections & Dental Trauma

26 Chapter 26: Psychiatric, Behavioral & Obstetric/Gynecologic Emergencies

26.1 Suicidal Ideation, Acute Agitation & Behavioral Emergencies 26.2 Acute Physical & Sexual Assault Care 26.3 Life-Threatening Vaginal Bleeding & Ectopic Pregnancy 26.4 Environmental Heat Stroke & Severe Hypothermia

27 Chapter 27: Acute Head, Neck & Neurologic Symptoms

27.1 Primary Acute Headaches: Migraine, Tension & Cluster 27.2 Concussion & Minor Closed Head Injury Evaluation 27.3 Transient Ischemic Attack Evaluation & ABCD2 Risk Scoring

28 Chapter 28: Acute Cranial Nerves, Hearing & Sensory Symptoms

28.1 Peripheral Neuropathies: Bell's Palsy, Carpal Tunnel & Radiculopathy 28.2 Acute Tinnitus, Sudden Sensorineural Hearing Loss & Cerumen Impaction 28.3 Acute Dizziness, Benign Paroxysmal Positional Vertigo & Vestibular Neuritis

29 Chapter 29: Acute Upper Respiratory Tract Infections

29.1 Acute Viral Rhinosinusitis vs. Bacterial Rhinosinusitis 29.2 Acute Pharyngitis: Group A Streptococcus & Centor Criteria 29.3 Acute Otitis Media, Otitis Externa & Serous Effusion

30 Chapter 30: Acute Lower Respiratory Infections & Cough

30.1 Influenza, COVID-19 & Viral Respiratory Syndromes 30.2 Acute Bronchitis & Lower Respiratory Tract Infections 30.3 Ambulatory Community-Acquired Pneumonia

31 Chapter 31: Allergic, Nasal & Non-Infectious Pulmonary Conditions

31.1 Allergic Rhinitis & Acute Non-Anaphylactic Allergic Reactions 31.2 Acute Dyspnea in Ambulatory Care 31.3 Interstitial Lung Diseases & Sarcoidosis Presentation

32 Chapter 32: Acute Chest, Cardiac & Vascular Symptoms

32.1 Palpitations Evaluation & Arrhythmia Triage in Primary Care 32.2 Deep Vein Thrombosis & Superficial Thrombophlebitis 32.3 Ambulatory Hypotension & Orthostasis Evaluation

33 Chapter 33: Acute Upper Gastrointestinal Conditions

33.1 Peptic Ulcer Disease & Gastritis 33.2 Dysphagia, Esophagitis & Acute Esophageal Disorders 33.3 Acute Nausea, Vomiting & Foodborne Illness

34 Chapter 34: Acute Lower Gastrointestinal Conditions

34.1 Acute Infectious Diarrhea & Gastroenteritis 34.2 Acute Constipation & Functional Bowel Changes 34.3 Ano-Rectal Disorders: Hemorrhoids, Fissures, Abscesses & Pruritus Ani

35 Chapter 35: Inflammatory, Functional & Malabsorptive GI Disorders

35.1 Acute Flares of Inflammatory Bowel Disease 35.2 Irritable Bowel Syndrome: Diagnosis, Subtyping & Management 35.3 Celiac Disease & Malabsorption Syndromes

36 Chapter 36: Acute Abdominal, Hepatic & Biliary Disorders

36.1 Ambulatory Abdominal & Pelvic Pain Triage 36.2 Acute Cholecystitis, Biliary Colic & Pancreatitis 36.3 Acute Liver Injury & Viral Hepatitis

37 Chapter 37: Acute Abdominal Wall, Hernias & Dental Conditions

37.1 Abdominal Wall, Inguinal & Ventral Hernias 37.2 Acute Dental Pain, Odontogenic Abscess & Aphthous Ulcers 37.3 Acute Edema: Unilateral vs. Bilateral Diagnostic Evaluation

38 Chapter 38: Acute Infectious Dermatoses

38.1 Bacterial Skin Infections: Impetigo, Cellulitis & Cutaneous Abscesses 38.2 Fungal Skin Infections: Tinea Corporis, Cruris, Pedis & Onychomycosis 38.3 Viral Cutaneous Infections: Herpes Simplex, Zoster & Molluscum Contagiosum

39 Chapter 39: Inflammatory, Allergic & Autoimmune Dermatoses

39.1 Atopic Dermatitis, Contact Dermatitis & Eczematous Flares 39.2 Non-Infectious Rashes: Urticaria, Drug Eruptions & Erythema Multiforme 39.3 Cutaneous Malignancies & Premalignant Lesions: AK, BCC, SCC & Melanoma

40 Chapter 40: Acute Shoulder, Elbow & Upper Extremity Injuries

40.1 Rotator Cuff Pathology, Tendinopathy & Shoulder Impingement 40.2 Lateral & Medial Epicondylitis, Olecranon Bursitis & Elbow Sprains 40.3 Wrist & Hand Soft-Tissue Injuries: De Quervain, TFCC & Finger Sprains

41 Chapter 41: Acute Knee, Ankle & Lower Extremity Injuries

41.1 Meniscal Tears, Ligamentous Knee Injuries & Patellofemoral Pain 41.2 Ankle Sprains, Ottawa Ankle Rules & Achilles Tendinopathy 41.3 Plantar Fasciitis, Shin Splints & Overuse Syndromes

42 Chapter 42: Acute Ambulatory Fractures & Dislocations

42.1 Distal Radius, Scaphoid & Common Upper Extremity Fractures 42.2 Metatarsal, Clavicle & Common Lower Extremity Fractures 42.3 Joint Dislocation Management: Nursemaid's Elbow & Shoulder Subluxation

43 Chapter 43: Acute Axial Musculoskeletal Pain & Falls

43.1 Acute Low Back Pain: Red Flags, Strain & Disc Herniation 43.2 Acute Cervical Strain, Whiplash & Axial Neck Pain 43.3 Evaluation of Falls in Ambulatory & Older Patients

44 Chapter 44: Acute Inflammatory Arthropathies & Generalized Pain

44.1 Acute Inflammatory Arthritis & Spondyloarthropathies 44.2 Myalgias, Rhabdomyolysis & Post-Viral Pain Syndromes 44.3 Acute Non-Headache Pain Management Strategies

45 Chapter 45: Acute Renal, Urinary & Genitourinary Conditions

45.1 Uncomplicated UTI, Pyelonephritis & Acute Urethritis 45.2 Hematuria Workup & Glomerulonephritis 45.3 Nephrolithiasis & Acute Urinary Tract Obstruction

46 Chapter 46: Acute Male Genitourinary & Prostatic Conditions

46.1 Acute Prostatitis, Epididymitis & Orchitis 46.2 Acute Scrotal Pain: Torsion vs Appendage, BPH & Male Genital Emergencies 46.3 Acute Urinary Retention & Incontinence Evaluation

47 Chapter 47: Acute Women's Health & Early Pregnancy Care

47.1 Early Pregnancy Diagnosis, Dating & Initial Complications 47.2 Abnormal Uterine Bleeding & Acute Menstrual Disorders 47.3 Premenstrual Syndrome & Premenstrual Dysphoric Disorder

48 Chapter 48: Breast Disorders, STIs & Pediatric Elimination

48.1 Palpable Breast Mass, Mastitis & Nipple Discharge 48.2 Sexually Transmitted Infections: Diagnosis, Staging & CDC Guidelines 48.3 Pediatric Enuresis & Encopresis

49 Chapter 49: Systemic Signs, Metabolic Dysregulation & Miscellaneous Infections

49.1 Acute Fever, Sepsis Screening & FUO in Primary Care 49.2 Acute Hyperglycemia & Symptomatic Hypoglycemia 49.3 Electrolyte Abnormalities: Mild-to-Moderate Disturbances 49.4 Vector-Borne, Tick-Borne & Rickettsial Illnesses

50 Chapter 50: Chronic Cardiovascular Diseases: Hypertension & Ischemia

50.1 Essential Hypertension Management: 2025 AHA/ACC Guideline & JNC Strategies 50.2 Chronic Coronary Artery Disease & Post-MI Secondary Prevention 50.3 Chronic Heart Failure: HFrEF, HFpEF & Quadruple GDMT

51 Chapter 51: Chronic Vascular, Valvular & Dyslipidemic Diseases

51.1 Peripheral Arterial Disease & Claudication 51.2 Chronic Valvular Heart Disease & Murmur Evaluation 51.3 Lipid Disorders & ASCVD Risk-Based Statin Therapy

52 Chapter 52: Chronic Respiratory Diseases: Asthma & COPD

52.1 Chronic Asthma Management: GINA Stepwise SMART Therapy 52.2 Chronic Obstructive Pulmonary Disease: GOLD Recommendations 52.3 Solitary Pulmonary Nodule Evaluation & Fleischner Society Criteria

53 Chapter 53: Chronic Metabolic Diseases: Diabetes Mellitus

53.1 Type 2 Diabetes Management: ADA Pharmacotherapy Algorithms 53.2 Type 1 Diabetes: Basal-Bolus Insulin, CGMs & Diabetic Complications 53.3 Diabetic Microvascular & Macrovascular Disease Surveillance

54 Chapter 54: Obesity, Nutrition & Metabolic Bone Diseases

54.1 Medical & Behavioral Management of Obesity & Incretin Mimetics 54.2 Osteoporosis & Metabolic Bone Disease: DEXA, FRAX & Antiresorptives 54.3 Nutritional Deficiencies: Vitamin D, B12, Iron & Malnutrition

55 Chapter 55: Chronic Endocrine Disorders

55.1 Primary & Subclinical Hypothyroidism, Hyperthyroidism & Nodules 55.2 Adrenal Disorders: Addison's Disease & Cushing's Syndrome 55.3 Hypercalcemia, Hyperparathyroidism & Pituitary Disorders

56 Chapter 56: Chronic Kidney Disease & Venous Disorders

56.1 Chronic Kidney Disease: KDIGO Staging & Renoprotective Therapy 56.2 Chronic Venous Insufficiency, Stasis Dermatitis & Lymphedema 56.3 Chronic Electrolyte & Acid-Base Management in CKD

57 Chapter 57: Chronic Gastrointestinal & Hepatic Diseases

57.1 Gastroesophageal Reflux Disease, Barrett's Esophagus & Dyspepsia 57.2 Chronic Liver Disease: MASLD/NAFLD, Cirrhosis & Portal Hypertension 57.3 Viral Hepatitis B & C: Long-Term Monitoring & DAA Therapy

58 Chapter 58: Colorectal Surveillance & Chronic Pancreaticobiliary Care

58.1 Post-Polypectomy Colorectal Polyp Surveillance Guidelines 58.2 Chronic Pancreatitis & Exocrine Pancreatic Insufficiency 58.3 Chronic Nausea, Gastroparesis & Functional GI Disorders

59 Chapter 59: Chronic Musculoskeletal & Rheumatologic Disorders

59.1 Osteoarthritis: Hip, Knee & Hand Management 59.2 Spinal Conditions: Spinal Stenosis, Spondylolisthesis & Compression Fractures 59.3 Chronic Myopathies & Fibromyalgia Syndrome

60 Chapter 60: Chronic Neurologic & Neurodegenerative Disorders

60.1 Dementia: Alzheimer's, Vascular & Lewy Body Disease 60.2 Parkinson's Disease & Essential Tremor 60.3 Epilepsy: Chronic Antiseizure Medications & Post-Stroke Care

61 Chapter 61: Chronic Peripheral Nerves, Pain & Sensory Disorders

61.1 Diabetic & Chronic Peripheral Neuropathies 61.2 Chronic Pain Syndromes & Chronic Daily Headaches 61.3 Chronic Tinnitus, Presbycusis & Persistent Dizziness

62 Chapter 62: Chronic Psychiatric Disorders

62.1 Major Depressive Disorder & Generalized Anxiety Disorder 62.2 Bipolar Disorder: Maintenance Pharmacotherapy & Lithium Monitoring 62.3 Adult & Pediatric Attention-Deficit/Hyperactivity Disorder

63 Chapter 63: Chronic Behavioral Health & Neurodevelopmental Conditions

63.1 Chronic Behavioral Conditions: PTSD, OCD & Somatization 63.2 Autism Spectrum Disorder & Intellectual Disabilities 63.3 Eating Disorders: Anorexia Nervosa, Bulimia & Binge Eating

64 Chapter 64: Chronic Substance Use Disorders & Tobacco Cessation

64.1 Alcohol Use Disorder: Pharmacotherapy & Relapse Prevention 64.2 Opioid & Stimulant Use Disorders: MOUD & Harm Reduction 64.3 Longitudinal Tobacco Cessation Pharmacotherapy

65 Chapter 65: Chronic Dermatologic Conditions

65.1 Acne Vulgaris, Rosacea & Seborrheic Dermatitis 65.2 Chronic Plaque Psoriasis & Biologic Therapies 65.3 Chronic Eczema, Hidradenitis Suppurativa & Cutaneous Lupus

66 Chapter 66: Chronic Reproductive, Infectious & Geriatric Special Care

66.1 Chronic Menstrual Disorders, Infertility & Sexual Dysfunction 66.2 Menopause Management & Hormone Replacement Therapy 66.3 Chronic HIV Infection Management & Primary Care Integration 66.4 Gender-Affirming Primary Care & Hormone Therapy 66.5 Advance Care Planning, Palliative Care & End-of-Life Symptom Control

67 Chapter 67: Continuity Care: Sleep, Fatigue, Cancer, Pregnancy & the Adult Preventive Visit

67.1 Chronic Insomnia & Obstructive Sleep Apnea 67.2 Chronic Malaise, Fatigue & ME/CFS 67.3 Primary Care During Cancer Treatment & Survivorship 67.4 Routine Prenatal Care & Longitudinal Pregnancy Management 67.5 The Periodic Adult Health Examination & Medicare Annual Wellness Visit

57.3 Viral Hepatitis B & C: Long-Term Monitoring & DAA Therapy

Key Takeaways Explain This Topic AI

Chronic Hepatitis B is defined by the persistence of Hepatitis B surface antigen (HBsAg) for >6 months; first-line oral nucleos(t)ide analogues with a high genetic barrier to resistance are entecavir, tenofovir disoproxil fumarate (TDF), and tenofovir alafenamide (TAF).

Tenofovir alafenamide (TAF) provides comparable antiviral efficacy to TDF but with significantly reduced systemic drug exposure, making it the preferred tenofovir formulation in patients aged >=60 years, those with osteopenia/osteoporosis, or preexisting renal impairment.

Prior to initiating immunosuppressive therapy or chemotherapy (especially B-cell depleting agents like rituximab), universal screening with HBsAg and total anti-HBc is mandatory; positive patients require prophylactic antiviral therapy to prevent catastrophic, fatal HBV reactivation.

Direct-acting antiviral (DAA) therapy achieves virologic cure (SVR12) in >95% to 98% of patients with chronic Hepatitis C using 8 to 12 weeks of all-oral, pangenotypic regimens; glecaprevir/pibrentasvir is strictly contraindicated in decompensated cirrhosis (Child-Pugh B or C).

Patients with advanced fibrosis (stage F3) or cirrhosis (stage F4) who achieve virologic cure (SVR12) for Hepatitis C STILL REQUIRE LIFELONG BIANNUAL ULTRASOUND SURVEILLANCE for hepatocellular carcinoma, whereas patients with mild-to-moderate fibrosis (F0-F2) require no further routine oncologic surveillance.

Last updated: September 2026

Chronic Hepatitis B Virus (HBV): Serologic Profiling, Natural History Phases & Treatment Indications

Hepatitis B virus (HBV) is a partially double-stranded DNA virus of the Hepadnaviridae family. Globally, more than 250 million individuals live with chronic HBV infection. In primary care, correctly interpreting serologic markers, identifying disease phases, and recognizing indications for antiviral therapy are vital to preventing cirrhosis, end-stage liver disease, and hepatocellular carcinoma (HCC).

Comprehensive Serologic Interpretation Panel HEPATITIS B SEROLOGIC PROFILES & INTERPRETATION

• Clinical Scenario HBsAg Anti-HBs Anti-HBc Total Anti-HBc IgM HBeAg HBV DNA
• ═══════════════════════════════════════════════════════════════════════════════════════════════
• Susceptible Neg Neg Neg Neg Neg Undetectable
• (Never exposed)

• Immunity via Neg POS Neg Neg Neg Undetectable
• Vaccination (>=10 mIU/mL)

• Immunity via Past Neg POS POS (IgG) Neg Neg Undetectable
• Natural Infection

• Acute Hepatitis B POS Neg POS POS POS Very High
• Infection

• Chronic Hepatitis B POS Neg POS (IgG) Neg +/- Variable
• (> 6 Months)

• Isolated Total Neg Neg POS (IgG) Neg Neg Undetectable
• Anti-HBc Positive* or Low
• ═══════════════════════════════════════════════════════════════════════════════════════════════
• *Isolated Anti-HBc Differential: 1) Distant resolved infection with waning anti-HBs titers (most common);
• 2) Occult HBV infection (detectable low-level HBV DNA in serum or liver); 3) False-positive test result;

4) Window period of acute infection (HBsAg has cleared, anti-HBs not yet detectable; anti-HBc IgM is positive).

The Four Clinical Phases of Chronic Hepatitis B

Chronic HBV is a dynamic disease classified into four distinct phases based on HBeAg status, serum HBV DNA viral load, serum ALT, and the presence of ongoing necroinflammatory liver injury:

Phase 1: Immune Tolerant (HBeAg-Positive Chronic Infection) :

Characteristics : HBeAg positive, extremely high serum HBV DNA levels (frequently >1,000,000 to >100,000,000 IU/mL), normal serum ALT, and minimal or no inflammation or fibrosis on histology.

Epidemiology : Classically seen in vertical (perinatal) transmission in endemic areas (e.g., East Asia). The immature immune system tolerates viral antigens without immune-mediated hepatocyte destruction.

Management : Antiviral treatment is NOT indicated . Antivirals show poor seroconversion rates in this phase. Monitor serum ALT and HBV DNA every 6 months to detect transition to the immune active phase.

Phase 2: Immune Active (HBeAg-Positive Chronic Hepatitis) :

Characteristics : HBeAg positive, high HBV DNA levels (>20,000 IU/mL), elevated serum ALT (>2 times the upper limit of normal [ULN]), and active histologic necroinflammation and progressive fibrosis.

Pathophysiology : Host CD8+ T-lymphocytes recognize viral antigens on hepatocyte membranes, driving immune-mediated lysis of infected hepatocytes.

Management : Antiviral treatment is DEFINITIVELY indicated to suppress viral replication, halt fibrosis progression, and promote HBeAg seroconversion to anti-HBe.

Phase 3: Inactive Carrier (HBeAg-Negative Chronic Infection / Immune Control) :

Characteristics : HBeAg negative, anti-HBe positive, low or undetectable serum HBV DNA ( <2,000 IU/mL ), consistently normal ALT, and inactive/stable liver histology.

Management : Antiviral treatment is not routinely indicated . Patients require lifelong surveillance with serum ALT and HBV DNA every 6 to 12 months, as reactivation can occur spontaneously or during immunosuppression.

Phase 4: HBeAg-Negative Immune Active (Immune Escape / Pre-Core Mutant) :

Characteristics : HBeAg negative, anti-HBe positive, elevated ALT, and fluctuating elevated serum HBV DNA ( >2,000 IU/mL ).

Pathophysiology : Harbor viral variants containing mutations in the pre-core (G1896A stop codon) or basal core promoter (BCP) region that prevent synthesis of HBeAg while preserving robust viral replication. The immune system attacks the liver despite the absence of circulating HBeAg.

Management : Antiviral treatment is DEFINITIVELY indicated , as this phase is associated with rapid progression to cirrhosis, decompensation, and HCC.

AASLD Indications for Initiating Antiviral Therapy

Treatment is indicated in patients meeting the following clinical criteria:

Elevated ALT (>2x ULN) AND Elevated HBV DNA : (>20,000 IU/mL if HBeAg-positive; >2,000 IU/mL if HBeAg-negative). Note: AASLD defines ULN for ALT as 35 U/L for men and 25 U/L for women .

Any Patient with Cirrhosis (Compensated or Decompensated) : Any cirrhotic patient with detectable serum HBV DNA, regardless of ALT level, requires immediate, indefinite antiviral therapy.

Evidence of Advanced Fibrosis / Cirrhosis (>=F2) on elastography or liver biopsy with elevated HBV DNA (>2,000 IU/mL), regardless of ALT.

Prevention of Perinatal Transmission : Pregnant women with high viral loads ( HBV DNA >200,000 IU/mL or >5.3 log10 IU/mL) measured at 24 to 28 weeks gestation must receive tenofovir (TDF) starting at 28 to 32 weeks gestation through delivery to prevent mother-to-child transmission (given in addition to neonatal infant HBIG and HBV vaccination within 12 hours of birth).

Preferred First-Line Oral Antivirals, Long-Term Safety & Reactivation Prophylaxis

Historic therapies with low genetic barriers to resistance (e.g., lamivudine, adefovir) are obsolete due to five-year resistance rates exceeding 70%. Current AASLD guidelines recommend oral nucleos(t)ide analogues with a high genetic barrier to resistance as first-line monotherapy.

First-Line Oral Nucleos(t)ide Analogues FIRST-LINE ORAL ANTIVIRAL AGENTS FOR CHRONIC HEPATITIS B

• Medication Dosage Resistance Rate Clinical Selection & Safety Nuances
• ═════════════════════════════════════════════════════════════════════════════════════════════════════
• Entecavir (ETV) 0.5 mg PO once daily < 1.2% at 5 yrs • Highly potent guanosine nucleoside analogue
• (1.0 mg if lamivudine- • Dose-reduce for CrCl <50 mL/min
• refractory / decomp) • Ineffective if prior lamivudine resistance
• Must rule out HIV coinfection before use
• (selects for M184V mutation in HIV)

• Tenofovir Disoproxil 300 mg PO once daily 0% documented • Highly potent nucleotide analogue
• Fumarate (TDF) • Preferred agent in pregnancy (Class B)
• Active against lamivudine-resistant strains
• Safety Concerns: Proximal renal tubular
• dysfunction (Fanconi syndrome) and loss of
• bone mineral density (osteopenia/osteoporosis)

• Tenofovir 25 mg PO once daily 0% documented • Phosphonamidate prodrug of tenofovir
• Alafenamide (TAF) with food • Enters hepatocytes efficiently, resulting in
• >90% lower circulating plasma tenofovir levels
• compared to TDF
• Significantly superior renal and bone safety
• PREFERRED over TDF in: Age >=60 years,
• osteopenia/osteoporosis, or CrCl 15-50 mL/min
• ═════════════════════════════════════════════════════════════════════════════════════════════════════

Treatment Duration & Monitoring :

In the vast majority of patients (and all cirrhotic patients), oral antiviral therapy is lifelong , as covalently closed circular DNA (cccDNA) persists within hepatocyte nuclei despite suppressed serum DNA.

Monitor serum ALT and quantitative HBV DNA every 3 to 6 months until viral suppression is achieved, then every 6 months indefinitely.

Monitor renal function (serum creatinine, eGFR, urinalysis for proteinuria/glycosuria, and serum phosphorus) every 6 months in patients receiving TDF.

Prevention of Hepatitis B Reactivation During Immunosuppression

Hepatitis B reactivation during cancer chemotherapy or systemic immunosuppressive therapy can trigger fulminant hepatic failure and death. Reactivation occurs when immunosuppression allows exponential uninhibited viral replication, followed by immune reconstitution that catastrophically destroys infected hepatocytes:

Mandatory Pre-Treatment Screening : All patients scheduled to receive cancer chemotherapy, systemic immunosuppressive biologics, or high-dose corticosteroids must undergo baseline screening with HBsAg AND Total Anti-HBc .

High-Risk Regimens : Therapies that deplete B-cells (e.g., anti-CD20 monoclonal antibodies: rituximab, ofatumumab, obinutuzumab ) carry a >10% to 20% risk of HBV reactivation, even in patients who are HBsAg-negative and only total anti-HBc positive (resolved natural infection). Other high-risk agents include anthracycline chemotherapy and high-dose prednisone (>=20 mg daily for >=4 weeks).

Prophylactic Management :

Any HBsAg-Positive Patient : Mandatory initiation of prophylactic antiviral therapy ( entecavir or tenofovir ) prior to or concurrently with the start of immunosuppression, continuing for at least 12 to 24 months after the cessation of immunosuppressive therapy.

HBsAg-Negative / Total Anti-HBc Positive Patients : If receiving B-cell depleting therapy (rituximab), prophylactic antiviral therapy is mandated . For lower-risk immunosuppression, serial monitoring of ALT and HBV DNA every 1 to 3 months with prompt pre-emptive antiviral initiation upon detectable viral DNA is acceptable.

Chronic Hepatitis C Virus (HCV): Natural History, Direct-Acting Antivirals & Post-SVR Surveillance

Hepatitis C virus (HCV) is an enveloped, positive-sense, single-stranded RNA virus of the Flaviviridae family. Spontaneous viral clearance occurs in only 15% to 25% of acutely infected individuals; the remaining 75% to 85% develop chronic Hepatitis C infection . Over a 20- to 30-year duration, 20% to 30% of chronically infected individuals progress to cirrhosis, liver failure, and hepatocellular carcinoma.

Universal Screening & Diagnostic Algorithm

Universal Screening Guidelines : The Centers for Disease Control and Prevention (CDC) and the U.S. Preventive Services Task Force (USPSTF) recommend universal one-time HCV screening for all adults aged 18 years and older , as well as screening during each pregnancy. Ongoing periodic screening is indicated for individuals with ongoing risk factors (e.g., injection drug use, hemodialysis).

Two-Step Diagnostic Sequence :

Step 1: Anti-HCV Antibody with Reflex Testing : Initial screening uses an enzyme immunoassay for anti-HCV antibodies.

Step 2: Quantitative HCV RNA PCR : Reflexively performed on all antibody-positive specimens.

Anti-HCV Positive / HCV RNA Undetectable : Indicates resolved past infection (spontaneous clearance or prior successful treatment) or a biological false-positive. No treatment indicated.

Anti-HCV Positive / HCV RNA Detectable : Confirms active chronic HCV infection . Proceed to pre-treatment evaluation.

Pre-Treatment Evaluation Checklist

Before initiating direct-acting antiviral (DAA) therapy, clinicians must complete a standardized clinical safety assessment:

Screen for Hepatitis B Coinfection (Black Box Warning) : DAAs rapidly eradicate HCV, removing the suppressive regulatory effect that HCV exerts on HBV replication. In coinfected patients, clearing HCV can trigger fatal acute Hepatitis B reactivation . Test every patient for HBsAg and Total Anti-HBc prior to initiating DAA therapy; if active HBV is detected, treat HBV concurrently.

Staging Liver Fibrosis & Cirrhosis : Calculate the FIB-4 index and/or perform transient elastography to differentiate non-cirrhotic patients (F0-F2) from those with advanced fibrosis (F3) or cirrhosis (F4). If cirrhosis is present, calculate the Child-Pugh score to distinguish compensated (Class A) from decompensated (Class B or C) disease.

Screen for Critical Drug-Drug Interactions (DDIs) : Review all concomitant medications using the University of Liverpool Hepatitis Drug Interactions database.

Modern Pangenotypic Direct-Acting Antiviral (DAA) Regimens

DAAs directly target specific non-structural viral proteins essential for viral replication. Modern all-oral, pangenotypic regimens cure >95% to 98% of patients across all HCV genotypes (1 through 6) with an 8- to 12-week course: PREFERRED FIRST-LINE PANGENOTYPIC DAA REGIMENS

• Regimen Components & Mechanism Dosing & Duration Clinical Pearls & Contraindications
• ═════════════════════════════════════════════════════════════════════════════════════════════════════════════
• Glecaprevir / • Glecaprevir (100 mg): 3 tablets taken • 8-Week duration in treatment-naive
• Pibrentasvir NS3/4A Protease Inhibitor TOGETHER once daily patients (with or without Child-Pugh A)
• (Mavyret) • Pibrentasvir (40 mg): WITH FOOD for • ABSOLUTELY CONTRAINDICATED in
• NS5A Replication Complex 8 WEEKS decompensated cirrhosis (Child-Pugh B or C)
• Inhibitor due to risk of fatal drug-induced
• hepatic decompensation

• Sofosbuvir / • Sofosbuvir (400 mg): 1 tablet PO once • 12-Week duration for all patients
• Velpatasvir NS5B Nucleotide Polymerase daily WITHOUT • Safe and approved in decompensated
• (Epclusa) Inhibitor regard to food for cirrhosis (Child-Pugh B/C; + ribavirin)
• Velpatasvir (100 mg): 12 WEEKS • Gastric pH Interaction: Velpatasvir
• NS5A Inhibitor requires acid for absorption. Avoid high-
• dose PPIs! Max omeprazole 20 mg given
• 4 hrs AFTER velpatasvir with food
• Amiodarone Contraindication: Fatal
• bradyarrhythmias reported with sofosbuvir
• ═════════════════════════════════════════════════════════════════════════════════════════════════════════════
• Definition of Cure: Sustained Virologic Response at 12 Weeks (SVR12)

Virologic cure is defined as achieving a Sustained Virologic Response at 12 weeks post-treatment (SVR12) , demonstrated by an undetectable quantitative HCV RNA level 12 weeks after completing DAA therapy . Achieving SVR12 is associated with profound long-term clinical benefits: >70% reduction in hepatocellular carcinoma risk, >80% reduction in liver-related mortality, and improvement in extrahepatic manifestations (e.g., resolution of mixed cryoglobulinemic vasculitis and improved glycemic control).

Post-SVR Long-Term Clinical Surveillance Protocol

Achieving virologic cure clears the infection, but management following SVR12 depends entirely upon the patient's pre-treatment hepatic fibrosis stage : POST-SVR SURVEILLANCE RECOMMENDATIONS

• Pre-Treatment Fibrosis Stage Long-Term Clinical Management & Surveillance Protocol
• ═════════════════════════════════════════════════════════════════════════════════════════════
• Non-Advanced Fibrosis • CONSIDERED COMPLETELY CURED
• (Stages F0, F1, or F2) • No ongoing hepatology follow-up or liver imaging required
• No routine serial HCV RNA testing unless reinfection is
• suspected due to persistent risk behaviors (e.g., active IVDU)
• Note: Anti-HCV antibodies remain positive for life and
• do not confer protective immunity; reinfection is possible

• Advanced Fibrosis (Stage F3) • MANDATORY LIFELONG HCC SURVEILLANCE
• or Cirrhosis (Stage F4) • Abdominal Ultrasound with or without serum AFP every 6 months
• Rationale: Although SVR12 significantly lowers the relative risk
• of HCC, the absolute annual risk remains >1% to 2% per year
• due to pre-existing genetic alterations in cirrhotic nodules
• Ongoing clinical surveillance for portal hypertension complications
• and annual screening for esophageal varices (if indicated)
• ═════════════════════════════════════════════════════════════════════════════════════════════

Loading diagram... Clinical Pathway for Hepatitis C Universal Screening, DAA Selection & Post-Cure Surveillance