Clinical question
Is there a difference in efficacy between the new, recombinant zoster vaccine (RZV) and the live zoster vaccine (LZV)?
Bottom line
Recombinant zoster vaccine appears more efficacious than LZV. Over 3 years, RZV prevents 1 additional case of herpes zoster (HZ) for about every 40 patients treated compared with 1 for every 60 to 70 with LZV. Both vaccines decrease the risk of postherpetic neuralgia. Recombinant zoster vaccine is more expensive and requires 2 injections whereas LZV only requires 1.
Evidence
There were 2 industry-supported placebo-controlled RCTs of RZV in immunocompetent patients without previous zoster infection or vaccine.1,2 Authors calculated numbers needed to treat (NNTs) (assuming linear disease rates) at 3 years to indirectly compare to LZV.
Studies of efficacy against HZ showed the following:
-In adults older than 50 years (N = 15 411; mean age 62), 0.08% had HZ with RZV versus 2.7% with placebo (NNT of about 40).1 In a comparable live-vaccine RCT, the NNT was about 70.3,4
-In adults older than 70 years (N = 13 900; mean age 76), 0.4% of patients had HZ versus 3.5% with placebo (NNT of about 40).2 In a comparable live-vaccine RCT (patients ≥ 60 years), the NNT was about 60.5
Studies of postherpetic neuralgia showed the following:
Serious adverse events occurred in 1.1% of those who had RZV, 1.9% of those who had LZV, and 1.3% of those who had placebo.1,5
Limitations with RZV studies were that blinding was questionable.1,2 No head-to-head RCTs comparing LZVs and RZVs with clinical outcomes exist. No RCTs with clinical outcomes exist of patients who previously had any zoster vaccine or HZ.
Context
Recombinant zoster vaccine differs from LZV in that 2 doses, 2 to 6 months apart are needed for RZV versus 1 for LZV.6,7 Recombinant zoster vaccine costs about 40% more (about $250 vs $180 for LZV).8
Current recommendations in Canada9 are to offer RZV to patients 50 years or older who previously received LZV or previously had HZ. In the United States,7 in those aged 50 to 59 years, RZV is recommended regardless of zoster infection or vaccine history; in those older than 60 years, either vaccine is given.
Neither vaccine is recommended for pregnant patients.6,7,9 Recombinant zoster vaccine might be considered in immunocompromised patients.9
Implementation
Annual rates of HZ increase with age, from about 4 in 1000 in those aged 40 to 64 to about 7 in 1000 in those 65 and older.10 Postherpetic neuralgia develops in 5% to 30% of HZ patients and also increases with age.11 Risk of HZ recurrence ranges from 2% to 6%.11 Patients who are or will be immunocompromised have a higher baseline and recurrence risk and should be encouraged to be vaccinated with RZV.9 If vaccinating patients who have had HZ or have received LZV, wait 1 year.9 Indirect comparison suggests, compared with LZV, 112 patients would have to be vaccinated with RZV to prevent 1 additional case of HZ.12
Notes
Tools for Practice articles in Canadian Family Physician are adapted from articles published on the Alberta College of Family Physicians (ACFP) website, summarizing medical evidence with a focus on topical issues and practice-modifying information. The ACFP summaries and the series in Canadian Family Physician are coordinated by Dr G. Michael Allan, and the summaries are co-authored by at least 1 practising family physician and are peer reviewed. Feedback is welcome and can be sent to toolsforpractice{at}cfpc.ca. Archived articles are available on the ACFP website: www.acfp.ca.
Footnotes
Competing interests
None declared
The opinions expressed in Tools for Practice articles are those of the authors and do not necessarily mirror the perspective and policy of the Alberta College of Family Physicians.
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