Question explored with the scientific record
How does the shingles vaccine work?
The shingles vaccines work by trying to restore the immune system's ability to keep the varicella-zoster virus in check, but the evidence for how well they do this depends heavily on which vaccine you look at and who paid for the study.
The virus that causes chickenpox never leaves your body. It hides in nerve cells, and your T-cells keep it suppressed. As you age, your T-cell response weakens, and the virus can reactivate as shingles [1, 2]. The live vaccine (Zostavax) tried to boost that T-cell response with a weakened virus. The newer recombinant vaccine (Shingrix) uses a single viral protein (glycoprotein E) plus a strong adjuvant (AS01B) to provoke a much larger immune response [20]. The evidence shows Shingrix produces a big spike in both antibodies and CD4+ T-cells after two doses [20, 22]. But the key question is whether that lab-measured spike translates into real protection that lasts.
The pivotal trials for Shingrix (ZOE-50 and ZOE-70) were funded by the manufacturer, GlaxoSmithKline. They reported about 97% efficacy against shingles in people aged 50 and older, and about 90% in those 70 and older, over a mean follow-up of about 3.5 years [22, 24, 28]. That sounds impressive, but the absolute risk in the placebo group was low: about 9 cases per 1,000 person-years [10]. So the vaccine prevents roughly 9 cases per 1,000 people per year. The trials also reported that about 81% of vaccine recipients had injection-site reactions and 66% had systemic reactions like fever or muscle pain [24]. The long-term follow-up claims protection holds at about 89% over roughly 10 years, but that data comes from the same manufacturer-funded extension studies [22].
| Group | Shingles cases per 1,000 person-years | Vaccine efficacy reported |
|---|---|---|
| Placebo (ZOE-50/70) | 9.1 | - |
| Shingrix recipients | 0.3 | 97.2% (50+) / 89.8% (70+) |
| Zostavax recipients (SPS trial) | ~5.6 | 51.3% (60+) |
The older live vaccine (Zostavax) was studied in a large manufacturer-funded trial of about 38,500 people. It reduced shingles by about 51% and postherpetic neuralgia by about 67% in people aged 60 and older [16, 25]. But its protection wanes significantly over time, dropping to about 32% by year 8 [25]. Shingrix clearly produces a stronger initial immune response, but the long-term safety data is thinner than the efficacy claims. The trials excluded people with certain conditions, and the safety data in immunocompromised populations comes from smaller studies with shorter follow-up [9, 23].
My call: Shingrix likely prevents shingles in older adults, with about 9 cases prevented per 1,000 people per year, but the evidence base is almost entirely manufacturer-funded and the long-term safety profile beyond 10 years is not established. Confidence: moderate.
Sources used 11
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Varicella-Zoster Virus-Specific Enzyme-Linked Immunospot Assay Responses and Zoster-Associated Pain in Herpes Zoster Subjects
Varicella-zoster virus–specific cell-mediated immunity is substantially boosted by a herpes zoster episode across age groups, with peak IFN-γ ELISPOT responses around two weeks after rash onset and waning by six months, while zoster-associated pain is most pronounced in older ad…
DOI: 10.1128/cvi.00095-12 -
Humoral and Cellular Immunity to Varicella‐Zoster Virus: An Overview
This paper provides a comprehensive overview of humoral and cellular immunity to Varicella-Zoster Virus (VZV), detailing the immune responses elicited by natural infection and vaccination, and their implications for disease prevention.
DOI: 10.1086/522123 -
Immunogenicity and Safety of a Candidate Subunit Adjuvanted Herpes Zoster Vaccine (HZ/su) in Adults Post Renal Transplant: a Phase III Randomized Clinical Trial
This collection of conference abstracts reports a cost-effectiveness Markov model of herpes zoster vaccination and phase II/III randomized trials showing that HZ/su was highly immunogenic with no identified safety concerns in renal transplant recipients and adults with solid tum…
DOI: 10.1093/ofid/ofx163.1044 -
Efficacy of varicella (VZV) vaccination: an update for the clinician
Varicella vaccines dramatically reduce varicella incidence and severe disease, with newer zoster vaccines offering strong, age-independent protection while research into ORF7 and neuroattenuated strategies points toward next-generation vaccines.
DOI: 10.1177/2051013616655980 -
Herpes zoster and vaccination: A clinical review
This clinical review evaluates the effectiveness of the herpes zoster vaccine in preventing herpes zoster and its complications, highlighting its cost-effectiveness particularly in individuals aged 70 and older, while also addressing issues related to insurance coverage.
DOI: 10.2146/ajhp090118 -
Understanding the immunology of Shingrix, a recombinant glycoprotein E adjuvanted herpes zoster vaccine
A comprehensive review detailing how the Shingrix recombinant gE herpes zoster vaccine, with the AS01_B adjuvant, elicits robust humoral and polyfunctional CD4+ T cell responses, achieving high and durable protection against herpes zoster across older adults and various immunoco…
DOI: 10.1016/j.coi.2019.02.009 -
What is Different about Recombinant Herpes Zoster Vaccine?
This narrative review concludes that recombinant zoster vaccine is more effective and longer-lasting than live zoster vaccine, has an acceptable safety profile, and is recommended for adults aged ≥50 years and severely immunocompromised adults aged ≥18 years.
DOI: 10.3904/kjm.2024.99.4.180 -
Efficacy, Effectiveness, and Safety of Herpes Zoster Vaccine in Immunocompromised Patients
A literature review assessing the efficacy, effectiveness, and safety of herpes zoster vaccines (ZVL and RZV) in immunocompromised adults, finding RZV generally effective and safe while ZVL shows variable protection and is often limited to specific milder immunosuppression scena…
DOI: 10.52533/johs.2023.31008 -
Herpes zoster subunit vaccine for the prevention of herpes zoster
This study reviews the efficacy and safety of the herpes zoster subunit vaccine (HZ/su vaccine) in preventing herpes zoster and postherpetic neuralgia in adults aged 50 and older, highlighting its superior efficacy compared to the live attenuated vaccine.
DOI: 10.2146/ajhp170399 -
Herpes zoster vaccination efficacy in the long-term care facility population: a qualitative systematic review
A qualitative systematic review synthesizing evidence on herpes zoster vaccination efficacy in adults over 60 residing in long-term care facilities, finding overall vaccine efficacy and safety signals across LTCF and community settings, but noting limited LTCF-specific data and …
DOI: 10.1080/03007995.2019.1600482 -
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