Study guide
6.3 Immunizations in Special Populations: Pregnancy, Asplenia & Immunocompromise
ABFM Family Medicine Certification Study Guide Exam
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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
6.3 Immunizations in Special Populations: Pregnancy, Asplenia & Immunocompromise
Key Takeaways Explain This Topic AI
In pregnancy, indicated vaccines include inactivated influenza (any trimester), Tdap (each pregnancy at 27–36 weeks), COVID-19, and maternal RSV Abrysvo (32–36 weeks during seasonal windows); live virus vaccines (MMR, varicella, LAIV) are strictly contraindicated due to theoretical teratogenicity.
Anatomical or functional asplenia (splenectomy, sickle cell disease) impairs clearance of encapsulated bacteria (S. pneumoniae, N. meningitidis, H. influenzae type b); patients require pneumococcal conjugate/polysaccharide vaccination, MenACWY (2-dose primary series 8 weeks apart, booster every 5 years), MenB (2 or 3-dose primary series, booster at 1 year then every 2–3 years), and 1 dose of Hib.
Elective splenectomy requires vaccine administration at least 14 days prior to surgery; for emergency trauma splenectomy, vaccines must be delayed until at least postoperative day 14 to avoid surgical immunosuppression blunting antibody responses.
Immunocompromised adults (HIV with CD4 < 200, solid organ transplant, anti-TNF or anti-CD20 therapy, prednisone >=20 mg/day for >=14 days) must never receive live attenuated vaccines; when initiating elective immunosuppression, live vaccines must be administered >=4 weeks prior and inactivated vaccines >=2 weeks prior.
Yellow fever vaccine is a live attenuated virus required for travel to endemic areas in sub-Saharan Africa and tropical South America; it carries a black-box warning/precaution in adults aged 60 and older due to increased risk of fatal vaccine-associated neurotropic disease (YEL-AND) and viscerotropic disease (YEL-AVD).
Last updated: September 2026
- Maternal Immunization: Protecting Mother and Neonate
- Physiologic and Immunologic Alterations in Pregnancy
Pregnancy involves complex immunological modulation characterized by a physiological shift from cell-mediated Th1 responses toward humoral Th2 immunity to prevent maternal fetal rejection. Concurrently, progressive diaphragmatic elevation by the gravid uterus reduces functional residual capacity, while maternal oxygen consumption and cardiac output increase by 30–50%. These alterations significantly increase maternal vulnerability to severe viral respiratory illness, acute respiratory distress syndrome (ARDS), sepsis, and obstetric complications (preeclampsia, preterm labor, stillbirth).
Concurrently, neonates possess naive B cells, deficient complement levels, and delayed endogenous IgG production until 2 to 3 months of age. Neonatal survival depends on transplacental transfer of maternal IgG via the neonatal Fc receptor (FcRn), which surges exponentially during the third trimester ( 28 to 36 weeks ).
Indicated Vaccines During Pregnancy
Inactivated Influenza Vaccine (IIV4 or RIV4) :
Timing : Administered during any trimester (first, second, or third).
Impact : Reduces maternal cardiopulmonary hospitalization by 40–50% and reduces laboratory-confirmed influenza in infants during the first 6 months of life by >50%.
Tdap (Tetanus, Reduced Diphtheria, Acellular Pertussis) :
Timing : Administered during each pregnancy between 27 and 36 weeks of gestation (optimally 27–32 weeks).
Impact : Maximizes transplacental transfer of anti-pertussis antibodies, preventing neonatal pertussis encephalopathy and death before the infant's 2-month DTaP series.
COVID-19 Updated Vaccine :
Timing : Safe and indicated in any trimester .
Impact : Prevents severe maternal illness, maternal ICU admission, mechanical ventilation, stillbirth, and neonatal hospitalization.
Maternal RSV Vaccine (Abrysvo ONLY) :
Formulation & Timing : Bivalent unadjuvanted recombinant RSV prefusion F vaccine administered between 32 0/7 and 36 6/7 weeks of gestation , seasonally from September through January in most continental US regions.
Contraindication of Competitor : Arexvy is strictly NOT approved in pregnancy due to a safety signal of preterm delivery.
Strictly Contraindicated Live Attenuated Vaccines in Pregnancy
Prohibited Vaccines : Measles-Mumps-Rubella (MMR) , Varicella (VAR) , Live Attenuated Influenza Vaccine (LAIV) , Oral Typhoid (Ty21a) , and Yellow Fever (unless travel to high-epidemic zone is unavoidable).
Pathophysiologic Rationale : Live attenuated viruses cross the placenta, posing theoretical risks of fetal replication, viremia, and teratogenesis:
Congenital Rubella Syndrome (CRS) : Sensorineural deafness, cataracts, microphthalmia, patent ductus arteriosus (PDA), pulmonary artery stenosis, microcephaly, and "blueberry muffin" skin lesions.
Congenital Varicella Syndrome : Cicatricial dermatomal skin scarring, limb hypoplasia, chorioretinitis, optic atrophy, and microcephaly.
Preconception Screening & Counseling : Non-pregnant women of childbearing age should be screened for rubella and varicella IgG. If non-immune, vaccinate prior to conception and strictly counsel to avoid pregnancy for at least 4 weeks (28 days) after receiving MMR or varicella vaccine.
Management of Inadvertent Administration : If MMR or varicella vaccine is inadvertently administered during pregnancy, or if conception occurs within 4 weeks of vaccination, the clinician must counsel the patient regarding theoretical risks but explicitly reassure that CDC pregnancy registries have documented zero cases of Congenital Rubella Syndrome or Congenital Varicella Syndrome . Inadvertent vaccination is NOT an indication for termination of pregnancy .
Deferred Vaccines : HPV vaccination is deferred during pregnancy due to lack of safety data. If started prior to pregnancy, pause the series and administer remaining doses postpartum without restarting.
- Anatomical and Functional Asplenia: Encapsulated Pathogen Vulnerability
- Pathophysiology of the Asplenic State
Etiologies : Surgical splenectomy (trauma, idiopathic thrombocytopenic purpura, hereditary spherocytosis, rupture), functional asplenia (sickle cell disease due to repeated microvascular vaso-occlusive splenic infarctions leading to complete autosplenectomy by age 5–6), celiac disease-associated splenic atrophy, and congenital asplenia.
Splenic Host Defense : The spleen contains approximately 25% of the body's lymphoid tissue. The splenic red pulp filters senescent erythrocytes and un-opsonized blood-borne pathogens through endothelial slits. Marginal zone macrophages phagocytose poorly opsonized bacteria, while marginal zone B cells produce IgM antibodies (specifically against polysaccharide capsular antigens) that trigger the classical and alternative complement pathways.
Overwhelming Post-Splenectomy Infection (OPSI) :
Clinical Course : A catastrophic medical emergency characterized by a mild flu-like prodrome rapidly progressing within 12–24 hours to high-grade bacteremia (10⁶–10⁸ CFU/mL), fulminant septic shock, disseminated intravascular coagulation (DIC), purpura fulminans, bilateral adrenal hemorrhage ( Waterhouse-Friderichsen syndrome ), and death in 50–70% of cases .
Causative Encapsulated Organisms : Streptococcus pneumoniae (responsible for 50–70% of OPSI cases), Neisseria meningitidis , and Haemophilus influenzae type b (Hib) .
Additional Pathogens : Capnocytophaga canimorsus (a fastidious gram-negative rod transmitted by dog or cat bites, causing overwhelming gangrenous sepsis in asplenics) and Babesia microti (an intraerythrocytic protozoan transmitted by Ixodes ticks, causing massive uncontrolled intravascular hemolysis).
Comprehensive Asplenia Immunization Protocol
Pathogen Target Vaccine Formulation Primary Regimen & Booster Cadence
Streptococcus pneumoniae PCV20 alone OR PCV21 alone OR PCV15 + PPSV23 Single dose of PCV20 or PCV21 (series complete); OR PCV15 followed by PPSV23 ≥ 8 weeks later (revaccinate PPSV23 5 years after first PPSV23).
Meningococcal (A, C, W, Y) MenACWY (Menveo or MenQuadfi) 2-dose primary series separated by 8 weeks ; followed by a booster dose every 5 years lifelong .
Meningococcal (Serogroup B) MenB-4C (Bexsero, 2 doses at 0, 1 mo) OR MenB-FHbp (Trumenba, 3 doses at 0, 1–2, 6 mos) Primary series; followed by a booster dose 1 year later , then every 2–3 years lifelong while at risk.
Haemophilus influenzae type b Hib conjugate 1 single lifetime dose if not previously received as an adult.
Important
MenACWY and MenB Are Non-Interchangeable : Serogroup B capsular polysaccharide mimics human fetal neural cell adhesion molecules (NCAM) and is non-immunogenic in standard conjugate vaccines; MenB vaccines utilize recombinant surface proteins (FHbp, NadA, NHBA). Asplenic patients REQUIRE BOTH MenACWY and MenB to ensure coverage against all five virulent meningococcal serogroups.
Splenectomy Perioperative Immunization Timing
Elective Splenectomy (e.g., planned hematologic splenectomy):
Administer all indicated vaccines AT LEAST 14 DAYS PRIOR to surgery .
Rationale : Allows intact splenic architecture to process antigens, present to T cells, and generate high titers of protective memory B cells before splenic tissue is excised.
Emergency Splenectomy (e.g., trauma, acute splenic rupture):
DELAY vaccination until AT LEAST POSTOPERATIVE DAY 14 .
Rationale : Administering vaccines in the immediate postoperative period yields severely blunted, subtherapeutic antibody titers due to trauma-induced acute immune suppression, inflammatory catabolism, and massive surgical stress.
Outpatient Asplenia Safety & Prophylaxis Rules
Standby Emergency Antibiotics : Provide the patient with an outpatient prescription for broad-spectrum antibiotics (e.g., amoxicillin-clavulanate 875/125 mg BID ; or levofloxacin 750 mg daily for severe penicillin allergy) to keep at home or while traveling. Instruct the patient to ingest the first dose immediately and proceed directly to an emergency department for ANY fever ≥ 38.0°C (100.4°F) or rigors.
Animal Bite Prophylaxis : Any dog or cat bite or scratch requires immediate medical attention, thorough wound cleansing, and prompt initiation of empiric amoxicillin-clavulanate to prevent fatal Capnocytophaga canimorsus bacteremia.
Tick Precautions : Counsel on avoiding tick-endemic brush to prevent Babesia microti parasitemia.
Medical Alert : Patients should continuously wear a medical alert bracelet indicating "Asplenic / High Sepsis Risk".
- Immunocompromised Adults: Stratification, Contraindications & Pre-Treatment Optimization
- Categorization of Immune Suppression
Severe / High-Level Immunocompromise :
- Hematologic malignancies (leukemia, lymphoma, multiple myeloma)
- Cancer chemotherapy or radiation therapy
Solid organ transplant recipients on maintenance immunosuppression (calcineurin inhibitors [tacrolimus, cyclosporine], antimetabolites [mycophenolate mofetil], mTOR inhibitors)
- Hematopoietic stem cell transplant (HSCT) recipients within 2 years
- Advanced or untreated HIV infection (CD4 count < 200 cells/μL or CD4 percentage < 14%)
Biologic immunomodulators: TNF-alpha inhibitors (infliximab, adalimumab, certolizumab, etanercept), B-cell depleting therapies (rituximab, ocrelizumab), IL-6 inhibitors (tocilizumab), JAK inhibitors (tofacitinib, baricitinib)
Systemic high-dose corticosteroids: Defined as ≥ 20 mg of prednisone equivalent daily for ≥ 14 consecutive days (or ≥ 2 mg/kg/day)
Low-Level Immunocompromise : Prednisone < 20 mg/day, alternate-day corticosteroids, low-dose methotrexate (≤ 0.4 mg/kg/week), azathioprine (≤ 3 mg/kg/day), HIV infection with CD4 ≥ 200 cells/μL.
Absolute Contraindication: Live Attenuated Vaccines
Live attenuated vaccines ( MMR, Varicella, LAIV, Yellow Fever, Oral Typhoid Ty21a, BCG ) are STRICTLY CONTRAINDICATED in severely immunocompromised hosts due to the risk of uncontrolled vaccine-strain viral or bacterial replication, tissue dissemination, and fatal disease.
The HIV Exception for MMR and Varicella : MMR and varicella vaccines are indicated in HIV-infected patients ONLY IF their CD4 count has been documented ≥ 200 cells/μL (and ≥ 15%) for at least 6 consecutive months . If CD4 < 200, live vaccines are strictly prohibited.
Pre-Immunosuppression Optimization Window
When elective biologic therapy, chemotherapy, or immunosuppression is planned:
Live Attenuated Vaccines : Must be administered AT LEAST 4 WEEKS PRIOR to initiating immunosuppressive therapy.
Inactivated Vaccines : Should be administered AT LEAST 2 WEEKS PRIOR to initiating immunosuppressive therapy to optimize immunologic priming and antibody generation.
Priority Inactivated Vaccines for Immunocompromised Hosts
Pneumococcal : Single-dose PCV20 alone, single-dose PCV21 alone, or PCV15 followed by PPSV23 ≥ 8 weeks later .
Recombinant Zoster Vaccine (Shingrix) : Recommended for all immunocompromised adults aged ≥ 19 years ; 2 doses administered at 0 and 1–2 months . Because Shingrix is a non-live recombinant sub-unit vaccine, it carries zero risk of viral replication.
Hepatitis B : High risk of reactivation during immunosuppression (especially with anti-CD20 rituximab or anti-TNF therapy). Universal adult recommendation; non-responders require repeat series (prefer Heplisav-B) and post-vaccination serologic monitoring.
COVID-19 : Updated annual vaccine, with additional doses permitted ≥ 2 months apart.
Household Contacts of Immunocompromised Patients
Household members should receive annual inactivated influenza vaccine , COVID-19 , MMR , and Varicella vaccines to establish a protective "cocoon".
If a household contact develops a vesicular rash after receiving the varicella vaccine, they should avoid direct contact with the immunocompromised patient until the lesions have completely crusted.
Avoid LAIV : Household contacts should avoid LAIV if the patient is severely immunocompromised and residing in a protective environment (e.g., bone marrow transplant unit); if LAIV is administered, contact must be avoided for 7 days.
- International Travel Vaccines: Yellow Fever, Typhoid, Japanese Encephalitis & Rabies
- 1. Yellow Fever Vaccine (YF-VAX)
Microbiology : Mosquito-borne flavivirus ( Aedes and Haemagogus mosquitoes) endemic to tropical sub-Saharan Africa and South America. Clinical manifestations include biphasic illness with fever, severe bradycardia relative to fever ( Faget's sign ), jaundice, black vomitus (hematemesis), acute kidney injury, shock, and DIC (mortality 20–50%).
Vaccine Characteristics : Live attenuated viral vaccine (17D strain) administered as a single subcutaneous dose. Documented on the International Certificate of Vaccination or Prophylaxis (ICVP, "yellow card") , which becomes legally valid 10 days after administration and confers lifelong immunity for most travelers.
Severe Adverse Reactions & Age ≥ 60 Precaution :
Age ≥ 60 years is a major ACIP precaution . Older primary vaccinees experience significantly elevated risks of two life-threatening adverse reactions:
Yellow Fever Vaccine-Associated Neurotropic Disease (YEL-AND) : Meningoencephalitis, Guillain-Barré syndrome, autoimmune demyelinating disease; onset 3–28 days post-vaccination (incidence ~1–2 per 100,000 in age ≥ 60).
Yellow Fever Vaccine-Associated Viscerotropic Disease (YEL-AVD) : Severe systemic illness mimicking wild-type yellow fever with fulminant hepatic necrosis, shock, DIC, and multi-organ failure; onset 2–8 days post-vaccination; mortality >60% (incidence ~1–3 per 100,000 in age ≥ 60).
Absolute Contraindications : Severe allergy to eggs/gelatin; severe immunosuppression (HIV with CD4 < 200, solid organ transplant, biologic therapy); thymus disorders (thymoma, myasthenia gravis, history of thymectomy); infants < 6 months.
Clinical Management : In travelers aged ≥ 60 with low exposure risk traveling to countries requiring yellow fever proof for entry, issue an official Medical Waiver Certificate of Exemption .
2. Typhoid Fever Vaccines
Pathogen : Salmonella enterica serotype Typhi (fecal-oral ingestion of contaminated food/water in South Asia, Africa, and Latin America). Causes enteric fever with step-ladder fever, abdominal pain, hepatosplenomegaly, "rose spots", and intestinal perforation.
Oral Live Attenuated Ty21a (Vivotif) : 4 enteric-coated capsules taken on alternate days (days 1, 3, 5, 7) with cool liquid 1 hour before meals. Must be kept refrigerated (2°C–8°C) . Must be completed ≥ 1 week prior to travel . Booster every 5 years . Strictly contraindicated in immunocompromised patients, pregnancy, and patients taking systemic antibiotics.
Injectable Vi Polysaccharide (Typhim Vi) : Single intramuscular injection administered ≥ 2 weeks prior to travel . Booster every 2 years . Inactivated sub-unit polysaccharide vaccine; safe in immunocompromised hosts and pregnancy .
3. Japanese Encephalitis Vaccine (IXIARO)
Pathogen : Mosquito-borne flavivirus ( Culex mosquitoes) endemic to rural agricultural areas of Asia (associated with rice paddies and domestic swine).
Vaccine : Inactivated, Vero cell culture-derived vaccine (IXIARO). Administered as a 2-dose intramuscular series at days 0 and 28 (accelerated 7-day schedule available for adults 18–65); completed ≥ 1 week before travel.
Indications : Travelers spending ≥ 1 month in endemic rural areas during transmission season, or short-term travelers with substantial outdoor rural exposure.
4. Rabies Pre-Exposure Prophylaxis (PrEP)
Target Travelers : Individuals traveling to rabies-endemic regions (Asia, Africa, Central/South America) with high animal exposure risk or delayed access to local medical facilities, spelunkers (bat contact), veterinarians, and wildlife biologists.
Updated ACIP 2-Dose Regimen (2022) : Administer 2 doses intramuscularly on days 0 and 7 (replacing the historical 3-dose regimen).
High-Yield Board Concept on Post-Exposure Prophylaxis (PEP) :
Pre-exposure prophylaxis does NOT eliminate the need for post-exposure evaluation following an animal bite.
However, it ELIMINATES THE REQUIREMENT FOR RABIES IMMUNE GLOBULIN (RIG) and REDUCES the post-exposure vaccine regimen from 4 doses to 2 doses (administered on days 0 and 3).