Shingrix Dosing Interval: 2-6 Months Between Doses
The recombinant zoster vaccine (Shingrix/RZV) should be administered as a 2-dose series with doses given 2-6 months apart, while the live-attenuated zoster vaccine (Zostavax/ZVL) is given as a single dose. 1, 2
Recombinant Zoster Vaccine (Shingrix/RZV)
Standard Dosing Schedule
- Two doses (0.5 mL each) administered intramuscularly, with the second dose given 2-6 months after the first dose 1, 2
- This applies to immunocompetent adults aged ≥50 years 2
- Also applies to immunocompromised adults aged ≥18 years at increased risk of herpes zoster 3, 1
Alternative Dosing Interval
- A 0- and 6-month schedule (extending beyond the standard 2-6 month window) demonstrated non-inferiority compared to the 0- and 2-month schedule based on antibody responses 1
- Real-world data shows that second doses administered at ≥180 days (6 months) did not impair vaccine effectiveness 4
- This provides flexibility when the recommended 2-6 month interval cannot be met
Importance of Second Dose Completion
- Two-dose vaccine effectiveness is 76% compared to only 64% for a single dose 5
- After one dose only, effectiveness drops substantially: 70% in year 1, declining to 45% in year 2 and remaining around 48-52% thereafter 5
- After two doses, effectiveness remains stable: 79% in year 1,75% in year 2, and 73% in years 3-4 5
- Real-world data shows 70% of recipients complete the series within 6 months and 80% within 12 months 6
Clinical Trial Efficacy Data
The pivotal trials demonstrated 2-dose efficacy of:
- 91.3% against herpes zoster in adults ≥70 years 1
- 88.8% against postherpetic neuralgia in adults ≥70 years 1
- Efficacy was maintained across age groups, including those ≥80 years 1
Live-Attenuated Zoster Vaccine (Zostavax/ZVL)
Single-Dose Administration
- Zostavax is administered as a single 0.65 mL dose subcutaneously 7
- Approved for adults aged 50-79 years 3
- No booster dose is licensed for this vaccine 7
- Contraindicated in immunocompromised individuals due to the live virus component 8, 3
Key Clinical Considerations
Timing in Immunocompromised Patients
- For patients requiring immunosuppressive therapy, ZVL (if used) should be given ≥4 weeks before beginning highly immunosuppressive therapy 8
- RZV is preferred in immunocompromised populations as it is a non-live vaccine 3, 1
Common Pitfall
The most critical error is failure to complete the 2-dose RZV series, which results in substantially reduced and rapidly waning protection. Healthcare providers should emphasize to patients that both doses are essential for optimal protection 6, 5.