When should an adult receive the herpes zoster vaccine (Shingrix), considering age ≥50, immunocompromised status, prior Zostavax vaccination, and pregnancy?

When to Get the Shingles Vaccine

All adults aged 50 years and older should receive the Shingrix vaccine as a 2-dose series (given 2–6 months apart), regardless of prior shingles history or previous Zostavax vaccination. 1, 2

Standard Age-Based Recommendations

Immunocompetent Adults

• Begin vaccination at age 50 years for all immunocompetent adults, with no upper age limit 1, 3
• The vaccine demonstrates 97.2% efficacy in preventing shingles in adults aged ≥50 years, with consistent protection across all age groups 1, 2
• Protection remains above 83.3% for at least 8 years and approximately 73% at 10 years post-vaccination 1

Dosing Schedule for Immunocompetent Adults

• First dose: Administer immediately upon reaching age 50 1
• Second dose: Give 2–6 months after the first dose 1, 2
• Minimum interval: 4 weeks between doses (if given earlier, the dose must be repeated) 1
• No maximum interval: If the second dose is delayed beyond 6 months, simply give it when the patient presents—do not restart the series 1

Immunocompromised Adults: Earlier Vaccination

Adults aged ≥18 years who are or will become immunocompromised should receive Shingrix regardless of age. 3, 4

Who Qualifies as Immunocompromised

• Hematologic malignancies (multiple myeloma, lymphoma, leukemia) 1, 2
• Solid organ or hematopoietic stem cell transplant recipients 1, 2
• HIV infection 1
• Autoimmune diseases requiring immunosuppressive therapy (including JAK inhibitors, biologics, or chronic high-dose glucocorticoids ≥20 mg/day prednisone equivalent) 1, 3
• Solid tumors undergoing chemotherapy 1

Modified Dosing Schedule for Immunocompromised Adults

• First dose: Administer immediately 1
• Second dose: Give 1–2 months after the first dose (shorter interval than immunocompetent adults to achieve earlier protection) 1, 3, 2
• Minimum interval: Still 4 weeks 1
• Optimal timing: Complete the full 2-dose series before starting highly immunosuppressive therapy whenever possible 1, 5

Special Timing for Transplant Recipients

• Autologous HSCT: Administer first dose 50–70 days post-transplant 1, 5
• Allogeneic HSCT: Wait at least 6–12 months post-transplant (some guidelines suggest ≥9 months) 5
• Solid organ transplant: Vaccinate 4–18 months post-transplant 1

Vaccination After Prior Zostavax

Adults who previously received Zostavax should receive the full 2-dose Shingrix series. 1

• Minimum interval: Wait at least 2 months after the last Zostavax dose before giving the first Shingrix dose 1
• Rationale: Zostavax efficacy declines to only 14.1% by year 10, providing inadequate long-term protection 1, 6
• Do not skip: Even if Zostavax was given recently, Shingrix is still recommended due to superior efficacy 1

Vaccination After a Shingles Episode

Adults who have had shingles should receive Shingrix once acute symptoms have resolved. 1, 5

• Minimum waiting period: At least 2 months after symptom resolution (allows complete immune recovery) 1, 5
• Rationale: A single shingles episode does not provide reliable protection; the 10-year cumulative recurrence risk is 10.3% 1, 5
• Dosing schedule: Follow the standard schedule based on immune status (2–6 months for immunocompetent; 1–2 months for immunocompromised) 1, 5

Pregnancy Considerations

Shingrix is not recommended during pregnancy. 7

• The older guideline from 2012 listed pregnancy as a contraindication for zoster vaccination 7
• Defer vaccination until after pregnancy completion 7
• Shingrix can be administered postpartum before hospital discharge if indicated 7

Critical Safety Points

Never Use Zostavax in Immunocompromised Patients

• Zostavax (live-attenuated vaccine) is absolutely contraindicated in any immunocompromised individual due to risk of disseminated VZV infection 1, 3, 5, 6
• Only Shingrix (recombinant vaccine) is appropriate for immunocompromised patients—it contains only a viral protein fragment, not live virus 1, 3, 4

Common Pitfalls to Avoid

• Do not delay vaccination to obtain VZV antibody titers—guidelines explicitly recommend against serologic testing before vaccination in adults ≥50 years 1
• Do not restart the series if the second dose is delayed beyond the recommended interval; simply give the second dose when the patient presents 1
• Do not give a third dose under any circumstance—the series consists of only two doses 1
• Do not confuse varicella (chickenpox) vaccine with zoster vaccine—they are different vaccines for different purposes 1

Expected Side Effects

Shingrix is more reactogenic than placebo but generally well-tolerated. 1, 2, 6

• Injection-site reactions: 9.5% experience grade 3 reactions (vs. 0.4% with placebo) 1
• Systemic symptoms: 11.4% report grade 3 symptoms such as fatigue, myalgia, or headache (vs. 2.4% with placebo) 1
• Duration: Most reactions are transient and resolve within approximately 4 days 1
• Serious adverse events: No difference between vaccine and placebo groups 1

Algorithm for Clinical Decision-Making

1. Is the patient ≥50 years old?

   • Yes: Recommend Shingrix 2-dose series (0,2–6 months) regardless of prior shingles or Zostavax history 1
   • No: Proceed to step 2

2. Is the patient aged 18–49 years AND immunocompromised (or will become immunocompromised)?

   • Yes: Recommend Shingrix 2-dose series with shortened schedule (0,1–2 months) 3, 4
   • No: Vaccination not indicated at this time; revisit at age 50 1, 3

3. Has the patient had shingles recently?

   • Yes: Wait at least 2 months after symptom resolution, then vaccinate per immune status 1, 5
   • No: Proceed with vaccination immediately

4. Did the patient previously receive Zostavax?

   • Yes: Wait at least 2 months after Zostavax, then give full 2-dose Shingrix series 1
   • No: Proceed with standard Shingrix schedule

5. Is the patient about to start immunosuppressive therapy (e.g., JAK inhibitors)?

   • Yes: Ideally complete both Shingrix doses before starting therapy; if urgent, give at least the first dose before therapy initiation 1
   • No: Proceed with standard schedule based on immune status