of herpes zoster or post- herpetic neuralgia should not receive Shingrix during their acute episode of herpes zoster (Dooling et al., 2018). Pregnancy and lactation Vaccine-associated risk with Shingrix in pregnant human patients was not evaluated. Female rats who received Shingrix did not experience any vaccine-related fetal malformations or variations. Because of the lack of information in human pregnancy, it may be prudent to avoid administering Shingrix to pregnant women (GlaxoSmithKline, 2021). It is unknown if Shingrix is excreted in breast milk, and no data is available to assess any effects of Shingrix on milk production or the breastfed infant. The manufacturer recommends weighing the benefits of breastfeeding and the mother’s clinical need for Shin - grix against any potential effects on the breastfed infant and the mother’s underlying condition (GlaxoSmithKline, 2021). Adverse reactions The most common adverse reactions reported in the initial stud- ies on Shingrix were injection-site reactions lasting for a median duration of two to three days. Pain was reported in 88% of Shin- grix recipients ages 50 to 59, as compared to 14% of placebo recipients in the same age group. Redness and swelling also oc- curred at higher rates with Shingrix when compared to placebo (GlaxoSmithKline, 2021). Other clinically significant adverse reactions reported in the initial studies include myalgia, fatigue, headache, shivering, fever, and GI side effects such as diarrhea, nausea, vomiting and abdominal pain. Systemic reactions were reported more frequently after the second dose of Shingrix as compared with the first. Rare serious adverse reactions that were found to potentially have a causal re- lationship with Shingrix included one case of lymphadenitis, one case of fever over 102.2°F, and three cases of optic ischemic neu- ropathy (Dooling et al., 2018; GlaxoSmithKline, 2021). Before vaccination, clinicians should discuss potential local and systemic adverse reactions with vaccine recipients. Since adverse reactions to the first dose of Shingrix did not strongly predict ad - verse reactions to the second dose, patients should be encour-
aged to complete both doses even if they experienced a mild to moderate reaction to the first dose (Dooling et al., 2018). Vaccine administration Before administration, Shingrix must be reconstituted. The prod- uct contains two vials; the first has a blue-green cap and contains the AS01B adjuvant suspension component. The second vial has a brown cap and contains the lyophilized varicella zoster virus glycoprotein E (gE) antigen component. The adjuvant suspen- sion should be slowly added to the antigen-containing vial, then gently mixed until the powder is dissolved completely. The mixed product should be an opalescent, colorless to pale-brown liquid, creating a single dose of 0.5mL (GlaxoSmithKline, 2021). After reconstitution, the vaccine should be administered intra- muscularly, with the preferred site being the deltoid region of the upper arm. If not used immediately after reconstitution, the recon- stituted vaccine can be stored under refrigeration between 36°F and 46°F and used within six hours. If not used within six hours, the reconstituted vaccine should be discarded (GlaxoSmithKline, 2021). Shingrix requires two doses for maximal efficacy, regardless of prior immunization with Zostavax. The second dose should be administered between two and six months after the first. Initial approval studies compared dosing at zero and two months to dosing at zero and six months; both dosing schedules produced comparable antibody levels. Immune response was also studied when Shingrix was administered at the same time as the quadriva- lent flu vaccine, and no interference in immune response to either product was observed (GlaxoSmithKline, 2020). Vaccine components and storage Shingrix is supplied with two components: the antigen compo- nent in a vial with a brown cap, and the adjuvant component in a vial with a blue-green cap. Both vials should be stored under re- frigeration, between 36°F and 46°F (2°C and 8°C). Vials should be protected from light, and if either vial becomes frozen, the frozen vial should be discarded. Shingrix is a preservative-free vaccine and does not contain any antibiotics. The vial stoppers do not contain latex (GlaxoSmithKline, 2020).
ACIP RECOMMENDATIONS
In January 2018, the Advisory Committee on Immunization Prac- tices (ACIP) released its official recommendations for the use of herpes zoster vaccines. The committee recommends using the re- combinant zoster vaccine Shingrix to prevent herpes zoster in im- munocompetent adults ages 50 and older. This recommendation was based on high efficacy rates of Shingrix, as well as slow rates of waning protection, when studied for four years post vaccina- tion. The committee noted that beginning vaccination at age 50 will help reduce the incidence of herpes zoster in midlife (Dooling et al., 2018). Other considerations Timing of Shingrix in patients previously vaccinated with Zostavax Clinicians should consider the patient’s age and the time since their Zostavax vaccination when determining when to administer Shingrix. Studies only evaluated immunogenicity and safety of Shingrix when administered more than five years after Zostavax; shorter intervals have not been evaluated to date. The ACIP notes that there are not any theoretical concerns or data indicating that Shingrix would be less effective or less safe if given within a short- er interval. In addition, since Zostavax demonstrated reduced effi - cacy in adults over the age of 70, a shorter interval for administer- ing Shingrix may be considered to reduce the risk of developing herpes zoster. Overall, the ACIP notes that Shingrix should not be administered less than two months after Zostavax (Dooling et al., 2018). Co-administration with other vaccinations As per the Centers for Disease Control and Prevention’s Best Prac- tice Guidelines for Immunization, adjuvanted and recombinant
vaccinations can be administered simultaneously with other adult vaccinations if given at different anatomic sites. Research on the administration of the quadrivalent flu vaccine with Shingrix did not indicate any concerns regarding safety or immune response to either vaccine. The concomitant administration of two adju- vanted vaccines has not been evaluated (Dooling et al., 2018). Missed or early doses of Shingrix If more than six months have passed since the initial dose of Shin- grix, the vaccine series does not need to be restarted. However, the ACIP notes that the safety and efficacy of alternate dosing regimens has not been studied, and patients may remain at risk of developing herpes zoster if longer-than-recommended intervals between the first and second doses are utilized. If the second dose of Shingrix is administered less than four weeks after the first dose, the ACIP recommends repeating the second dose (Dooling et al., 2018). Special populations History of herpes zoster Because of the potentially recurrent nature of herpes zoster, adults who have previously developed shingles should receive Shingrix. If the patient is currently experiencing a shingles episode, immu- nization should be delayed until the acute phase has passed and symptoms have resolved (Dooling et al., 2018). Patients who are immunocompromised The ACIP recommends using Shingrix in patients taking low-dose immunosuppressive medications, such as less than 20 mg per day of prednisone, as well as patients expecting to begin immuno- suppressive therapy and those who have recently recovered from an immunosuppressive illness. Since patients taking moderate- to
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