Recombinant Herpes Zoster Vaccine

Recombinant herpes zoster vaccine (RZV) is a non-live, adjuvanted vaccine designed to prevent herpes zoster, commonly known as shingles, and associated complications, including postherpetic neuralgia, which is persistent nerve pain after the rash resolves. The vaccine contains a recombinant form of glycoprotein E, an important protein of the varicella-zoster virus, combined with an adjuvant system that enhances the immune response. It does not contain live varicella-zoster virus and cannot cause shingles through vaccine-virus replication.

RZV works by stimulating virus-specific immune responses that help the body control reactivation of varicella-zoster virus, which remains dormant in nerve tissue after chickenpox. The vaccine is administered by intramuscular injection, usually as a two-dose series. In the United States and European Union, the licensed vaccine is indicated for older adults and, under specified conditions, adults at increased risk because of immunodeficiency or immunosuppression. Eligibility and recommendations differ by country and should follow local regulatory guidance and immunisation policies.

Vaccination is clinically important because shingles can cause acute pain, skin complications, and prolonged nerve pain, particularly in older or immunocompromised people. RZV reduces the risk of disease but does not treat an active shingles episode or prevent primary chickenpox infection.

Recombinant zoster vaccine was developed using varicella-zoster virus glycoprotein E and an adjuvant system to produce a strong, targeted immune response without using live virus. Its clinical development included the ZOE-50 and ZOE-70 phase 3 trials, which evaluated protection against shingles in older adults, alongside subsequent studies in immunocompromised populations. The United States Food and Drug Administration (FDA) initially approved the vaccine in October 2017 for adults aged 50 years and older. In July 2021, the FDA expanded its indication to include adults aged 18 years and older who are or will be at increased risk of shingles because of immunodeficiency or immunosuppression caused by disease or therapy. The European Medicines Agency (EMA) authorised Shingrix in the European Union on 21 March 2018 for adults aged 50 years and older and adults aged 18 years and older at increased risk. Recommendations from public health authorities, including the US Centers for Disease Control and Prevention (CDC), support its use in eligible populations. Approval status and eligibility in India or other jurisdictions should be verified against current local regulatory information.

Recombinant herpes zoster vaccine is indicated to prevent herpes zoster and associated complications in eligible adults. Under US FDA labelling and CDC recommendations, it is used routinely in adults aged 50 years and older and in adults aged 19 years and older who are or will be immunodeficient or immunosuppressed because of disease or therapy. European authorisation covers adults aged 50 years and older and adults aged 18 years and older at increased risk of herpes zoster. The vaccine may be recommended regardless of a previous episode of shingles, subject to local guidance and the absence of an acute episode requiring vaccination to be deferred. It is a preventive vaccine, not a treatment for active shingles, postherpetic neuralgia, or primary varicella infection. Decisions for transplant recipients, people receiving cancer treatment, and individuals using immunosuppressive medicines should consider the underlying condition, treatment schedule, immune status, and applicable national recommendations.

Recombinant herpes zoster vaccine is administered by intramuscular injection, preferably into the deltoid muscle of the upper arm. The standard adult regimen consists of two doses, with the second dose generally given 2–6 months after the first. For eligible immunocompromised adults who would benefit from faster completion, the second dose may be given 1–2 months after the first, according to applicable recommendations and product labelling. If the second dose is delayed beyond the recommended interval, the series generally does not need to be restarted; the outstanding dose should be administered as advised by a healthcare professional. The vaccine is preventive, so there is no conventional treatment duration or routine maintenance schedule after the primary series. Vaccination should be deferred during an acute episode of shingles and administered when the person is clinically appropriate for vaccination. Before administration, healthcare professionals should review allergy history, immune status, current treatment, and local prescribing guidance.

Common adverse effects include pain, redness, and swelling at the injection site, as well as muscle pain, fatigue, headache, shivering, fever, and gastrointestinal symptoms such as nausea. These reactions are generally temporary and usually resolve within approximately 2–3 days. Some people may experience symptoms intense enough to interfere briefly with usual daily activities. Reactogenicity can vary between individuals and may be more noticeable after the second dose. Supportive measures may be considered when appropriate, following advice from a healthcare professional. Patients should be counselled that short-lived local or systemic reactions are expected possibilities and do not necessarily indicate an infection or an abnormal vaccine response. Persistent, worsening, or unusual symptoms should be assessed clinically rather than automatically attributed to vaccination.

Severe allergic reactions, including anaphylaxis, are possible, and a history of a severe allergic reaction to a previous dose or a vaccine component is a contraindication to further administration. The US prescribing information also includes a warning concerning Guillain–Barré syndrome (GBS), based on a potential increased risk observed after vaccination, particularly in older adults; clinicians should assess relevant history and discuss the benefit–risk balance when appropriate. RZV is non-live, but vaccination timing requires careful consideration in people with significant immunosuppression, because immune responses may vary. It should not be used to treat active shingles, and vaccination should generally be postponed during an acute episode. Serious or persistent neurological symptoms, breathing difficulty, facial or throat swelling, or other signs of a severe allergic reaction require urgent medical assessment. Treatment interruption or discontinuation in this context means withholding a planned vaccine dose pending clinical evaluation, rather than stopping a continuing drug regimen.

Before vaccination, assess previous severe allergic reactions, current or planned immunosuppressive treatment, recent or active shingles, and the timing of other vaccines. RZV is a non-live vaccine and may be suitable for many immunocompromised adults, but the timing of vaccination in relation to chemotherapy, transplantation, or other immunosuppressive therapies should be individualised to optimise immune response while avoiding unnecessary delays. Pregnancy-specific evidence is limited, so vaccination decisions should follow current local product information and professional guidance. Breastfeeding and other special-population considerations should likewise be assessed against the applicable label. Classic pharmacokinetic drug interactions are not expected because the vaccine is not a systemically acting small-molecule medicine; however, immunosuppressive therapies can affect the response to vaccination. Other vaccines may sometimes be administered during the same visit at separate anatomical sites, provided local recommendations and product guidance permit this.

Prescribers should confirm the patient's eligibility under local immunisation recommendations and distinguish preventive vaccination from treatment of active herpes zoster. Review the history of severe allergic reactions, previous zoster vaccination, current immune status, and planned immunosuppressive therapy before scheduling the series. For patients receiving chemotherapy or preparing for transplantation, coordinate vaccination with the treating specialist to optimise immune response without compromising essential treatment. Explain the expected duration of common reactions, the importance of completing both doses, and the need to arrange the second dose within the recommended interval. If the second dose is overdue, follow current guidance rather than automatically restarting the series. Pharmacists should verify product storage, reconstitution requirements, expiry, dose preparation, and intramuscular administration instructions in the relevant product information. Ensure appropriate readiness to manage anaphylaxis and counsel patients to seek urgent assessment for severe allergic or neurological symptoms. Document each dose and provide a clear reminder for the next appointment.