the fourth year after vaccination in this older patient population. Shingrix was also associated with lower rates of post-herpetic neuralgia in this age group when compared with placebo, with four cases reported in the vaccine group and 28 cases reported in the placebo group (GlaxoSmithKline, 2021). When data were pooled between the two studies for patients ages 70 and older, researchers found a 91.3% reduction in the risk of developing shingles in those who have received two doses of Shingrix (GlaxoSmithKline, 2021). Since data are not currently available to evaluate the long-term efficacy of Shingrix vaccination, modeled data based on the first four years of clinical trial data, as well as expert opinion, was used to assess long-term efficacy. Modeled data show that in adults over the age of 50, efficacy would wane to zero 19 years after vaccination, assuming vaccinated patients received two doses of Shingrix at recommended dosing intervals (Dooling et al., 2018). Contraindications and precautions Shingrix should not be administered to patients with a history of a severe allergic reaction to a previous dose of Shingrix or to any component of the vaccine. Patients who have a current episode 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 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
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). 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).
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