What is the recommended dose of Zostavax (herpes zoster vaccine)?

Zostavax Dosing

Zostavax is administered as a single 0.5 mL subcutaneous dose containing a minimum of 1350 plaque-forming units (PFU) of Oka/Merck varicella zoster virus. 1

Important Context: Zostavax Is No Longer Preferred

While you asked about Zostavax dosing, you should be aware that Zostavax has been superseded by Shingrix (recombinant zoster vaccine) as the preferred herpes zoster vaccine due to significantly superior efficacy and durability. 2, 3

Key Differences in Efficacy:

• Zostavax efficacy: 51.3% against herpes zoster and 66.5% against postherpetic neuralgia in adults ≥60 years 1
• Shingrix efficacy: 97.2% against herpes zoster in adults ≥50 years 1, 3
• Zostavax efficacy declines markedly with age (70% in ages 50-59 vs. only 18% in those ≥80 years) 1
• Zostavax protection wanes substantially over time (from 51.3% to 21.2% by years 7-11 post-vaccination) 1

Zostavax Administration Details

Dosing:

• Single dose of 0.5 mL administered subcutaneously 1
• Contains minimum 1350 PFU (approximately 3.13 log10 PFU) of Oka/Merck VZV 1
• No booster dose is part of the standard regimen 4, 5

Storage and Handling:

• Store frozen at average temperature of -15°C or colder until reconstitution 1
• After reconstitution, keep at room temperature for maximum of 30 minutes 1

Approved Age Range:

• Licensed for adults aged 50-79 years 2
• Originally recommended by ACIP for adults ≥60 years 6

Critical Contraindications

Zostavax is contraindicated in immunocompromised patients due to the theoretical risk of serious disease from the live attenuated virus. 2 This includes patients with:

• Primary or acquired immunodeficiency states 2
• Those receiving immunosuppressive therapy 3
• Hematologic malignancies 3

Current Clinical Recommendation

Patients who previously received Zostavax should receive the two-dose Shingrix series, with no minimum interval required between the different vaccines. 2, 3 This recommendation exists because:

• Shingrix provides substantially higher and more durable protection 2, 3
• Shingrix can be safely administered to immunocompromised patients, unlike Zostavax 2, 3
• Shingrix maintains efficacy above 83.3% for at least 8 years with minimal waning 3

Shingrix Dosing (For Reference):

• Two-dose series: 0.5 mL intramuscularly, with second dose given 2-6 months after the first 3
• For immunocompromised adults ≥18 years: shorter interval of 1-2 months between doses 3