What are the recommendations for the shingles (Herpes Zoster) vaccine in adults aged 50 and older, including those with a history of shingles or weakened immune systems, such as cancer or Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS)?

Shingles Vaccine Recommendations for Adults

Primary Recommendation for Immunocompetent Adults

All immunocompetent adults aged 50 years and older should receive the recombinant zoster vaccine (Shingrix/RZV) as a two-dose series administered 2-6 months apart, regardless of prior shingles history. 1, 2, 3

Vaccine Choice and Efficacy

• RZV (Shingrix) is strongly preferred over the live attenuated zoster vaccine (Zostavax/ZVL) due to superior efficacy: 97.2% effectiveness in preventing herpes zoster across all age groups 50 and older, compared to ZVL's 51.3-69.8% efficacy that declines significantly with age 1

• RZV maintains protection above 83.3% for up to 8 years and 73% at 10 years, while ZVL efficacy drops to only 21.2% by years 7-11 post-vaccination 1

• RZV demonstrates 88.8% efficacy against postherpetic neuralgia (PHN), the most debilitating complication of shingles 1

Dosing Schedule

• Standard schedule: First dose at Month 0, second dose 2-6 months later (minimum 4 weeks between doses) 2, 3

• The two-dose series is essential for optimal protection; both doses must be completed 2, 3

Immunocompromised Adults: Critical Expanded Indication

Adults aged 18 years and older who are or will be immunocompromised should receive RZV regardless of age, with a modified dosing schedule. 2, 3, 4

Eligible Immunocompromised Populations

• HIV/AIDS patients 2, 4
• Active cancer or hematologic malignancies (including multiple myeloma) 1, 4
• Solid organ or hematopoietic stem cell transplant recipients 1, 4
• Patients on immunosuppressive therapy (biologics, JAK inhibitors, high-dose corticosteroids) 2, 4
• Autoimmune diseases requiring immunosuppression 2, 4

Modified Schedule for Immunocompromised

• Accelerated dosing: First dose at Month 0, second dose 1-2 months later (rather than 2-6 months) to provide faster protection in this vulnerable population 2, 3

• RZV is the ONLY appropriate vaccine for immunocompromised patients—ZVL (live attenuated vaccine) is absolutely contraindicated due to risk of vaccine-strain varicella infection 2, 4

Prior Shingles History Does Not Change Recommendations

• Vaccination is recommended even if the patient has had shingles previously, as recurrence risk is 10.3% over 10 years 2

• Wait at least 2 months after acute shingles symptoms resolve before administering RZV 2

• Prior shingles does not provide reliable immunity against future episodes 2

Patients Previously Vaccinated with Zostavax

Adults who previously received ZVL should receive the full two-dose RZV series due to ZVL's declining efficacy (14.1% by year 10). 2

• Minimum interval: Wait at least 2 months between ZVL and the first RZV dose 2

• Both RZV doses are required even with prior ZVL vaccination 2

Safety Profile and Expected Adverse Events

Common Reactions (Mild to Moderate, Resolve Within 4 Days)

• Injection site reactions are very common: Pain (78-88%), redness (30-38%), swelling (18-26%) 3, 5

• Systemic symptoms are frequent: Myalgia (45-58%), fatigue (45-64%), headache (30-44%), shivering (25-31%), fever (18-28%), gastrointestinal symptoms (17-28%) 3, 5

• Grade 3 injection site reactions occur in 9.5% and systemic symptoms in 11.4%, significantly higher than placebo (0.4% and 2.4% respectively) 1

Serious Safety Considerations

• No increased risk of death or serious adverse events compared to placebo in large clinical trials 1, 5

• Postmarketing surveillance identified an increased risk of Guillain-Barré syndrome during the 42 days following vaccination, though absolute risk remains low 3

• Syncope can occur with any injectable vaccine; have patients sit or lie down during administration 3

Impact on Vaccine Completion

• Higher dropout rate for second dose in vaccinated group (RR 1.25) due to reactogenicity after first dose 5

• Counseling patients about expected side effects before the first dose is critical to prevent series non-completion 6

• Concerns about tolerability make individuals 1.83 times more likely to receive only one dose rather than completing the series 6

Contraindications

Absolute contraindication: History of severe allergic reaction (anaphylaxis) to any vaccine component or after a previous RZV dose 3

• Pregnancy is NOT listed as a contraindication for RZV (unlike ZVL), though data are limited 3

Critical Clinical Pitfalls to Avoid

• Do not use live attenuated ZVL in any immunocompromised patient—this includes patients on biologics, immunomodulators, or those with HIV, cancer, or transplant history 2, 4

• Do not assume patients under age 50 cannot receive RZV—those who are immunocompromised qualify starting at age 18 3, 4

• Do not skip the second dose—single-dose efficacy is inadequate; both doses are required for optimal protection 2, 3

• Do not confuse FDA approval age (50+) with older ACIP recommendations (60+)—current guidelines from 2017 onward recommend starting at age 50 for immunocompetent adults 2, 7, 4

• Do not delay vaccination to conduct varicella serology in adults ≥50 years—RZV is indicated regardless of chickenpox history or varicella antibody status 2

• Do not administer RZV for primary varicella (chickenpox) prevention—it is not indicated for this purpose 3

Special Consideration: Varicella-Seronegative Individuals

• If confirmed VZV-seronegative by antibody testing, patients should receive the varicella vaccine (2 doses, 4 weeks apart) rather than or before RZV 8

• Most adults (88-91%) are VZV-seropositive even without recalled chickenpox history, making routine serology testing unnecessary in the ≥50 age group 8