Zoster Vaccine (Inactivated)

Introduction Overview

Generic Name

zoster vaccine (inactivated)

Brand Name

Shingrix

Dosage Form

single-dose vial kit for reconstitution and prefilled single-dose syringe (0.5 mL)

Drug Class

viral vaccines

Pharmacokinetics

Shingrix, as a recombinant subunit vaccine, exhibits pharmacokinetics distinct from traditional small-molecule drugs due to its nature as a biologic agent. Absorption occurs through intramuscular administration, typically into the deltoid muscle. The formulation contains recombinant glycoprotein E (gE) antigen combined with the AS01B adjuvant system, enhancing immune response kinetics. Upon intramuscular injection, the vaccine's antigen is taken up by local antigen-presenting cells (APCs), particularly dendritic cells, initiating the immune activation cascade. Distribution involves migration of these APCs to regional lymph nodes where activation and clonal expansion of gE-specific CD4+ T-helper cells occur, facilitating both cellular and humoral immunity. There is no systemic distribution akin to small-molecule pharmacokinetics; instead, the immune system mediates the vaccine's effects. Metabolism is immunologic rather than enzymatic — the viral antigen and adjuvants are processed and presented by immune cells, with no biotransformation by hepatic enzymes. Elimination involves degradation of vaccine components by proteolytic enzymes within immune cells and clearance of immune complexes through normal physiological pathways. The recombinant antigen and adjuvant components do not accumulate and are effectively eliminated by the body's immune processing mechanisms. Clinical immunogenicity data demonstrate a robust and sustained immune response mediated through these pharmacokinetic pathways, with peak antibody titers and T-cell responses maintained over years, thereby conferring effective protection against herpes zoster.

Dosage Forms

Available Dosage Forms:
Shingrix is supplied as:
- Single-dose vial kit for reconstitution containing a lyophilized recombinant glycoprotein E antigen powder and an adjuvant suspension vial
- Prefilled single-dose syringe containing 0.5 mL of adjuvant suspension ready for use

Dosages for Adults and Adolescents:
- The standard dose for adults aged 18 years and older who are immunocompromised or for prevention in adults aged 50 years and older is two intramuscular injections of 0.5 mL each
- The two-dose series is administered with the second dose given 2 to 6 months after the first dose
- In immunocompromised individuals, dosing interval may be shortened to 1 to 2 months between doses

Specific Patient Populations:
- Adults aged 50 years and older for shingles prevention
- Adults aged 18 years and older who are immunodeficient or immunosuppressed due to known disease or therapy
- Safety and efficacy not established in children under 18 years
- Use in pregnant or breastfeeding women requires careful consideration; limited data available

Clinical guidelines emphasize adherence to the two-dose regimen to ensure optimal immunogenicity and effectiveness. Administration is intramuscular, preferably into the deltoid muscle, and the vaccine is not recommended for treatment of active herpes zoster or chickenpox infections.

Mechanism Of Action

Shingrix operates through a recombinant subunit vaccine mechanism targeting the varicella-zoster virus (VZV), specifically the glycoprotein E (gE) antigen, which is the major viral envelope protein essential for viral replication and cell-to-cell spread. By presenting this antigen to the immune system, Shingrix induces a robust, targeted immune response without exposure to live virus components, enhancing safety especially in immunocompromised populations. The vaccine incorporates the AS01B adjuvant system, a liposome-based formulation containing MPL (monophosphoryl lipid A) and QS-21, a saponin derivative. This combination potentiates the innate immune system by activating Toll-like receptor 4 (TLR4) pathways and stimulating antigen-presenting cells, thereby enhancing both humoral and cellular adaptive immunity.

Upon intramuscular injection, the vaccine components are internalized by dendritic cells and macrophages which migrate to regional lymph nodes. There, these antigen-presenting cells present gE epitopes via MHC class II molecules to CD4+ T-helper cells, promoting a strong Th1-biased cellular immune response characterized by IFN-gamma secretion. Concurrently, B cells are activated to produce high-affinity neutralizing antibodies against gE, contributing to humoral immunity. This dual stimulation is critical for effective prevention of herpes zoster, as cellular immunity plays a central role in controlling latent VZV reactivation.

Compared to live attenuated vaccines such as Zostavax, Shingrix’s recombinant approach demonstrates significantly higher efficacy and duration of protection, particularly in older adults where immune senescence may impair responses to live vaccines. Clinical studies show efficacy exceeding 90% across age groups, with sustained immunogenicity lasting for several years. The mechanism circumvents risks associated with live vaccines, such as potential reactivation of latent virus, making Shingrix preferable especially in immunocompromised individuals.

Emerging research also suggests that the adjuvant system may induce epigenetic and metabolic reprogramming of innate immune cells, contributing to an enhanced and long-lasting trained immunity. The vaccine’s unique mechanism not only primes adaptive immunity but also enhances innate defenses, broadening its protective capacity against herpes zoster.

Pharmacological Actions

Induces strong cell-mediated and humoral immune responses against varicella-zoster virus glycoprotein E antigen.
Stimulates Toll-like receptor 4 via MPL, enhancing antigen-presenting cell activation.
Enhances maturation and migration of dendritic cells to lymph nodes.
Promotes Th1-biased CD4+ T-helper cellular immunity critical for controlling latent viral reactivation.
Activates B cells to produce neutralizing antibodies against gE antigen.
Acts as a recombinant subunit vaccine, avoiding the risks associated with live attenuated vaccines.
Provides long-lasting immunity, with protective effects documented up to at least 7 years post-vaccination.
Combines antigen with AS01B adjuvant system, which synergistically intensifies immune response strength and durability.
Reduces incidence, severity, and complications of herpes zoster infection.
Does not provide therapeutic effect for active herpes zoster infection but prevents occurrence in at-risk populations.

Therapeutic Or Clinical Uses

Prevention of herpes zoster (shingles) in adults aged 50 years and older.
Prevention of herpes zoster in adults aged 18 years and older who are immunocompromised or immunosuppressed due to disease or therapy.
Reduction in risk of postherpetic neuralgia associated with shingles.
Immunization to prevent reactivation of latent varicella-zoster virus.
Use as a primary prophylactic vaccine in older adults, with high efficacy demonstrated in clinical trials.
Recommended for patients with increased risk of herpes zoster due to immune status.
Alternative to live attenuated zoster vaccines, particularly for immunocompromised populations.

Side Or Adverse Effects

Pain at the injection site is commonly reported.
Redness and swelling localized to the site of injection.
Muscle pain (myalgia) following vaccination.
Fatigue and general malaise are frequent systemic reactions.
Headache reported in a significant proportion post-vaccination.
Shivering and fever as part of systemic reactogenicity.
Gastrointestinal symptoms including nausea, vomiting, diarrhea, and stomach pain.
Rare but serious allergic reactions including anaphylaxis; signs include hives, facial swelling, difficulty breathing.
Increased risk of Guillain-Barré syndrome observed within 42 days post-vaccination in postmarketing studies.
Fainting (syncope) may occur particularly in individuals with prior history related to vaccinations.
Local lymphadenopathy has been reported occasionally.
Adverse events typically resolve within a few days without sequelae.
Severe adverse events are extremely rare but warrant immediate medical attention.
Reporting of side effects to healthcare providers and regulatory agencies is encouraged to monitor vaccine safety.
Temporary exacerbation of injection site reactions can occur with the second dose.

Precautions

Do not administer to individuals with a history of life-threatening allergic reaction to any component of the vaccine.
Inform healthcare provider of any history of allergic reactions to vaccines or vaccine components.
Use caution in patients with underlying chronic illnesses or immunodeficiency; vaccination benefits should outweigh risks.
Monitor patients with a prior history of Guillain-Barré syndrome carefully before and after vaccination.
Advise patients to report any neurological symptoms promptly post-vaccination.
Use with caution during pregnancy; animal studies are insufficient, and potential risks are unknown.
Breastfeeding mothers should consult healthcare providers prior to vaccination due to limited safety data.
Patients with bleeding disorders should be vaccinated cautiously due to risk of hematoma with intramuscular injection.
Monitor for syncope during and after vaccine administration, especially in adolescents and young adults.
Coadministration with other vaccines is generally safe but should follow clinical guidelines.
Ensure proper refrigeration and handling of vaccine components prior to administration.
Avoid administration during febrile illness or acute infection unless benefits outweigh risks.
Patients should be advised about the potential for local and systemic reactions post-vaccination.
Emphasize the importance of completing the two-dose series for optimal protection.

Warnings

Do not administer to individuals with known severe allergic reactions to Shingrix or its components.
Discontinue administration if a life-threatening allergic reaction occurs after any vaccine dose.
Increased risk of Guillain-Barré syndrome has been observed; clinicians should monitor for neurological symptoms such as weakness, tingling, balance difficulties, or bowel/bladder dysfunction.
Syncope associated with injectable vaccines may occur; observe patients for 15 minutes post-injection.
Use in pregnancy and lactation should be considered only if potential benefits justify potential risks.
Vaccination does not treat active herpes zoster or chickenpox infections; Shingrix is not indicated for acute therapeutic use.
Patients with moderate or severe acute illness should defer vaccination until recovery.
Possible transient exacerbation of vaccine site reactions after second dose requires patient counseling.
Uncommonly, fever after vaccination may require symptomatic treatment and monitoring.
Inappropriate storage or handling can reduce vaccine efficacy; assure cold chain adherence.
Not evaluated for use in individuals younger than 18 years.
Shingrix should not be used interchangeably with live attenuated zoster vaccines; adherence to current immunization guidelines is essential.

Contraindication

Known hypersensitivity or severe allergic reaction (e.g., anaphylaxis) to any component of Shingrix.
History of a life-threatening allergic reaction after a prior dose of Shingrix.
Current herpes zoster infection or active varicella infection.
Severe acute illness or infection with or without fever, until resolution.
Contraindicated in individuals with documented severe allergy to recombinant glycoprotein E, MPL, QS-21, or any excipients such as polysorbate 80.
Do not use as a treatment for active herpes zoster or chickenpox.
Not recommended in children and adolescents under 18 years of age due to lack of safety and efficacy data.
Avoid use in patients with uncontrolled bleeding disorders without adequate medical support.
Contraindicated for simultaneous administration with other live vaccines unless specifically recommended.
Not indicated for immunization in pregnant women unless benefits clearly outweigh risks.

Drug Interactions

No significant pharmacokinetic drug interactions expected due to vaccine nature; however, immunosuppressive therapies may reduce vaccine efficacy.
Immunomodulatory drugs (e.g., corticosteroids, chemotherapy agents) can attenuate immune response to Shingrix.
Concurrent administration with other vaccines, including influenza vaccine, is generally considered safe and does not impair immunogenicity.
Herbal supplements and vitamins have not demonstrated significant impact on Shingrix but should be reported to healthcare providers.
Live vaccines should not be coadministered simultaneously, as they may interfere with immune response.
No effect of Shingrix on cytochrome P450 enzymes or drug metabolism pathways.
No evidence of Shingrix interacting with anticoagulants, antihypertensives, or other common chronic medications.
Immunosuppressive treatments may necessitate timing considerations for optimal vaccine response.
Patients should inform healthcare providers of all medications to assess potential immunosuppression.
Vaccination during therapy with biologics or monoclonal antibodies requires clinician judgment based on immune status.
No reported interactions causing increased adverse effects with commonly used drugs.
No dosage adjustments recommended based on concomitant drug use.
Potential impacts of experimental immune therapies on vaccine efficacy require clinical monitoring.
The vaccine does not affect metabolism or clearance of systemic concomitant medications.
Supplemental zinc or antioxidants do not interfere with vaccine-induced immune responses.

Preparations Of The Drug

Each 0.5 mL dose contains 50 mcg recombinant glycoprotein E antigen.
Contains AS01B adjuvant comprising 50 mcg monophosphoryl lipid A (MPL) and 50 mcg QS-21.
Inactive ingredients include 20 mg sucrose, 4.385 mg sodium chloride, 1 mg DOPC, 0.54 mg potassium dihydrogen phosphate, 0.25 mg cholesterol, 0.160 mg sodium dihydrogen phosphate dihydrate, 0.15 mg disodium phosphate anhydrous, 0.116 mg dipotassium phosphate, and 0.08 mg polysorbate 80 per dose.
Shingrix is a preservative-free vaccine.
Vial stoppers and syringe components are made without natural rubber latex.
May contain trace residuals of host cell proteins (≤3.0%) and DNA (≤2.1 picograms) derived from the manufacturing cell lines.
Formulated as a two-vial kit: one vial of lyophilized antigen powder and one vial or syringe of adjuvant suspension requiring reconstitution before administration.
Stored refrigerated between 2°C and 8°C; do not freeze.
Packaged in prefilled syringes or as kits requiring reconstitution under aseptic conditions.
Supplied by GlaxoSmithKline Biologics with U.S. license number 1617.
Manufacturing includes recombinant DNA technology using Chinese hamster ovary (CHO) cells.
The vaccine must be prepared shortly before administration following the manufacturer’s instructions to ensure stability and potency.
No preservatives included to reduce risk of hypersensitivity reactions.
Designed for intramuscular injection only; not for intravenous or subcutaneous use.
Released with stringent quality controls to assure consistency and immunogenicity.