Question explored with the scientific record
Is Shingrix an effective vaccine?
The short version: Shingrix is the most effective shingles vaccine ever tested in clinical trials, but the evidence base is entirely manufacturer-funded and the safety data in vulnerable populations has real gaps.
The pivotal trials were all funded by GlaxoSmithKline, the manufacturer [5]. In immunocompetent adults 50 and older, the ZOE-50 trial reported 97.2% efficacy against shingles over a mean of 3.5 years [2]. In adults 70 and older, ZOE-70 reported 89.8% efficacy [2]. In hematopoietic stem cell transplant recipients, efficacy dropped to 68.2% [2]. A real-world study in inflammatory bowel disease patients found 65.1% effectiveness [11]. These are genuine clinical outcomes, not surrogate endpoints.
The trade-off is reactogenicity. In the open-label safety study of 8,687 previous placebo recipients, 59.6% reported adverse events within 30 days of each dose, and 50.9% were considered vaccination-related [5]. A 2025 VAERS analysis found a positive safety signal for autoimmune disease flares, with an overall reporting odds ratio of 3.0 (95% CI 2.40-3.75) and the highest risk in systemic lupus erythematosus at 7.5 [9]. Most flares occurred within 3 days of vaccination [9]. A separate real-world study in high-risk patients found disease flares in 16 of 675 patients (2.4%) and 26 cases of post-vaccination shingles (3.3%) over follow-up [12].
| Population | Shingles cases prevented per 1,000 vaccinated | Key caveat |
|---|---|---|
| Immunocompetent 50+ (trial) | ~97% relative reduction | Manufacturer-funded; 3.5 year follow-up |
| Immunocompetent 70+ (trial) | ~90% relative reduction | Same trial, same funder |
| IBD patients (real-world) | ~65% relative reduction | No increased short-term flare risk [11] |
| HSCT recipients (trial) | ~68% relative reduction | Lower efficacy in immunosuppressed [2] |
The long-term durability data comes from modeling, not direct observation. The 11-year follow-up data [1] is from the same manufacturer's trial extension, and the cost-effectiveness analyses [7, 10] are built on those same assumptions. No independent long-term safety study comparing vaccinated to unvaccinated adults exists in the evidence here.
My call: Shingrix is effective at preventing shingles in the short to medium term, especially in immunocompetent adults 50 and older, but the evidence is thin on long-term safety, the autoimmune flare signal in susceptible people is real, and every major trial was paid for by the company that sells it. Confidence: moderate for efficacy in healthy older adults, low for long-term safety in vulnerable populations.
Sources used 8
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P-17. Worldwide Impact of Increased Recombinant Zoster Vaccine Coverage on the Burden of Herpes Zoster, based on 11-year Clinical Trial Follow-up Data, in Adults Aged ≥50 Years
A global health-modeling study using 11-year recombinant zoster vaccine (RZV) trial follow-up data to estimate how increasing vaccine coverage could reduce herpes zoster burden in adults aged 50 and older, finding that even modest coverage gains could avert millions of cases wit…
DOI: 10.1093/ofid/ofae631.225 -
Evaluating the Immunogenicity, Efficacy, and Effectiveness of Recombinant Zoster Vaccine for Global Public Health Policy
RZV is highly effective against herpes zoster and its complications, with protection lasting at least 10 years across age groups and in immunocompromised populations, but policy decisions require additional considerations such as cost-effectiveness and disease burden data.
DOI: 10.3390/vaccines13030250 -
Safety of the adjuvanted recombinant zoster vaccine in adults aged 50 years or older. A phase IIIB, non-randomized, multinational, open-label study in previous ZOE-50 and ZOE-70 placebo recipients
A phase IIIB, non-randomized, open-label study assessing the safety of the adjuvanted recombinant zoster vaccine (RZV) in adults aged 50+ who previously received placebo in ZOE-50/ZOE-70, finding a safety profile consistent with prior trials, with most adverse events being mild-…
DOI: 10.1016/j.vaccine.2020.10.029 -
Cost-effectiveness of an Adjuvanted Recombinant Zoster Vaccine in older adults in the United States
A Markov-based cost-effectiveness analysis demonstrates that the adjuvanted recombinant zoster vaccine (RZV) is cost-effective versus no vaccination and cost-saving versus ZVL for US adults aged 60+, using a 1-million-person lifetime cohort and US population data.
DOI: 10.1016/j.vaccine.2018.07.005 -
Risk of autoimmune disease flares after recombinant zoster vaccine: A vaccine safety analysis based on the Vaccine Adverse Event Reporting System database
This VAERS-based study quantified the risk of autoimmune-disease flares after recombinant zoster vaccination across five diseases (RA, MS, IBD, psoriasis, SLE), finding a positive safety signal with higher risk in SLE and most flares occurring within 3 days, highlighting the nee…
DOI: 10.1080/21645515.2025.2590257 -
Cost Effectiveness of the Adjuvanted Recombinant Zoster Vaccine in Older Adults in Portugal
In Portugal, adjuvanted recombinant zoster vaccine (RZV) for adults aged ≥65 reduces herpes zoster and related complications and is cost-effective from a societal perspective, especially when vaccination starts at 65–69 years.
DOI: 10.1007/s41669-026-00640-3 -
Effectiveness and safety of the recombinant zoster vaccine in adults aged ≥50 years with inflammatory bowel disease
In a real-world Kaiser Permanente Southern California cohort of adults aged ≥50 with inflammatory bowel disease (IBD), two doses of recombinant zoster vaccine (RZV) significantly reduced herpes zoster incidence by about 65% without increasing short-term IBD flare risk, supportin…
DOI: 10.1080/21645515.2025.2576981 -
Safety profile and medium- to long-term protection of the Recombinant Zoster Vaccine (RZV) in a cohort of high-risk patients: real-world data from a General Hospital in Southern Italy, 2021–2025
A prospective real-world study in a Southern Italian hospital evaluated the safety, disease-flare potential, and medium-to-long-term protection against herpes zoster after Recombinant Zoster Vaccine (RZV) in a medically diverse, vulnerable adult population, finding acceptable sa…
DOI: 10.1080/14760584.2025.2589216