What is the recommended prevention and treatment for shingles and postherpetic neuralgia (PHN) using the zoster vaccine?

Zoster Vaccine and Postherpetic Neuralgia Prevention

Primary Recommendation

All immunocompetent adults aged ≥50 years should receive the recombinant zoster vaccine (Shingrix/RZV) as a 2-dose series (doses separated by 2-6 months) to prevent both herpes zoster and postherpetic neuralgia, with RZV strongly preferred over the older live-attenuated vaccine (Zostavax/ZVL). 1

Vaccine Selection: RZV vs ZVL

RZV (Shingrix) is the definitively superior choice based on the following evidence:

• Efficacy against herpes zoster: RZV demonstrates 97.2% efficacy in adults ≥50 years (ZOE-50 trial) and 89.8% in adults ≥70 years (ZOE-70 trial), compared to ZVL's 51.3% overall efficacy that declines dramatically with age (70% at ages 50-59 but only 18% at age ≥80 years) 1

• Efficacy against PHN: RZV provides 88.8% protection against postherpetic neuralgia in adults ≥70 years, compared to ZVL's 66.5% efficacy that wanes to 35.4% by 7-11 years post-vaccination 1

• Duration of protection: RZV maintains efficacy above 83.3% for at least 8 years and 73% at 10 years, while ZVL efficacy drops to only 21.2% for herpes zoster and 35.4% for PHN by years 7-11 1

• Consistent efficacy across age groups: RZV maintains comparable efficacy across all age groups ≥50 years, whereas ZVL efficacy decreases substantially with increasing age 1

Vaccination Schedule and Administration

For immunocompetent adults ≥50 years:

• Administer first dose immediately
• Give second dose 2-6 months after the first dose (minimum interval: 4 weeks) 1, 2
• Both doses required for optimal protection 2

For immunocompromised adults ≥18 years:

• RZV is recommended (ZVL is contraindicated in this population) 1, 3
• Consider shortened schedule with second dose at 1-2 months after first dose 3, 2

Special Clinical Scenarios

Previous Zostavax vaccination:

• Administer RZV regardless of prior ZVL receipt 1, 2
• Minimum interval: 2 months after last ZVL dose (though this is typically already satisfied) 2
• Rationale: ZVL efficacy wanes to only 14.1% by year 10 2

Previous herpes zoster infection:

• Vaccinate with RZV once acute symptoms resolve, typically waiting at least 2 months after the episode 2, 4
• Prior infection does not provide reliable protection against recurrence (10.3% cumulative recurrence risk at 10 years) 4

Immunocompromised patients:

• RZV is the preferred vaccine for solid cancers, hematologic malignancies, and patients on immunosuppressive therapy 1, 3
• Safe to administer on low-dose glucocorticoids (<10 mg/day prednisone equivalent) 2
• Can be given during neutropenic periods as it is non-live, though consider timing between chemotherapy cycles when feasible 2

Safety Profile

Common adverse events with RZV:

• Grade 3 injection-site reactions: 9.5% (vs 0.4% placebo) 1
• Systemic symptoms: 11.4% (vs 2.4% placebo) 1, 2
• These reactions are transient and mild-to-moderate 3

Important safety distinction:

• No difference in serious adverse events or deaths between RZV and placebo 1, 2
• RZV is non-live and safe for immunocompromised patients, unlike ZVL which is contraindicated 1, 3

Prevention of Postherpetic Neuralgia

Vaccination is the most effective prevention strategy for PHN:

• PHN is definitively the most common complication of herpes zoster, particularly in older adults 4
• RZV reduces PHN incidence by 88.8% in adults ≥70 years 1
• The CDC defines PHN as debilitating pain persisting weeks to months after rash resolution 4

Risk factors for PHN:

• Advanced age (most significant risk factor) 4
• Severity of acute herpes zoster pain and rash 4
• Immunocompromised status 4

Treatment Considerations (Not Prevention)

For acute herpes zoster treatment (separate from vaccination):

• Valacyclovir is FDA-approved for herpes zoster treatment in immunocompetent adults 5
• Efficacy established when initiated within 72 hours of rash onset 5
• In adults ≥50 years with established PHN, median duration of post-herpetic pain was 40-43 days with valacyclovir vs 59 days with acyclovir 5

For established PHN treatment:

• Gabapentin is FDA-approved for PHN management in patients with pain >3 months after rash healing 6
• Demonstrated efficacy at doses of 1800-3600 mg/day divided three times daily 6

Critical Clinical Pitfalls to Avoid

• Do not delay RZV vaccination in adults ≥50 years waiting for arbitrary age thresholds—the Advisory Committee on Immunization Practices now recommends starting at age 50, superseding older guidelines that recommended age 60 2

• Do not use ZVL in immunocompromised patients—it is absolutely contraindicated due to risk of disseminated VZV infection; only RZV is appropriate 3, 2

• Do not assume prior herpes zoster provides adequate protection—recurrence risk is substantial and vaccination is still indicated 2, 4

• Do not withhold RZV due to lack of chickenpox history—88-91% of adults are VZV-seropositive even without recalled chickenpox, and vaccination is recommended regardless of history 3

• Do not administer only one dose of RZV—both doses are required for optimal and sustained protection 2