by Ashley McPhee, PharmD Candidate and Lisa Hutchison, PharmD, MPH, University of Arkansas for Medical Sciences (UAMS) College of Pharmacy
Herpes zoster, commonly known as shingles, is a viral infection that causes a painful rash. The rash usually occurs on one side from the middle of the back toward the chest, but it can occur in other areas as well. Shingles is the result of reactivation of the existing but undeveloped varicella zoster virus (VZV). This is the virus that causes chickenpox.1 Nearly all older adults have the VZV dormant in their nervous system because they were exposed to chicken pox as a child.2 Protection from reactivation is dependent on cell-mediated immunity. This type of immunity decreases as we age, if we have certain diseases, or medications. An example of disease and medications include Human immunodeficiency virus (HIV) and high dose steroid treatment. The average age for shingles to occur is about 64 years.1
Current 2017 Centers for Disease Control (CDC) guidelines recommend shingles vaccination. This vaccine (Zostavax©), is a live, attenuated vaccine. This means that the vaccine is living and produces disease, but it has been weakened so that it produces immunity but not illness.3 Currently, the CDC recommends that adults ages 60 years and older get one dose of the vaccine. They should get it even if they have had shingles before. Since the vaccine is live, patients who are pregnant, have severe immunodeficiency, or on systemic immunosuppressive therapy should not receive it. In addition, patients with malignant conditions such as those that affect bone marrow or patients with HIV and a CD4+ T-lymphocyte count less than 200 cells/µl should also not receive the vaccine.4 These individuals may not be able to mount a response to the virus to create antibodies.
However, a new shingles vaccine (Shingrix©) will soon be available. This vaccine is a non-live, recombinant subunit containing a piece of the Herpes zoster virus that will stimulate the immune system most efficiently. The new vaccine is given intramuscularly in two separate doses, and is indicated for patients 50 years and older. This vaccine was shown to produce the desired effect 90% of the time, across all age groups.2 The previous vaccine was only about 50% effective.3 t In October 2017 the CDC’s Advisory Committee on Immunization Practices (ACIP) voted in favor of recommending this new vaccine for patients who are 50 years and older even if they have received Zostavax previously. They also determined that Shingrex© would be preferred over Zostavax© for these individuals.2 One concern is that the trials with this vaccine did not include patients who were immunocompromised.5 The vaccine is not live, so this should not necessarily be a contraindication for vaccination. However, ACIP does mention immunocompetence as part of their requirement for recommendation at this time.2 It is possible the recommendation will change based on post-marketing data after the general population has been receiving the vaccine. For now, it provides a great alternative vaccine for patients who were previously not eligible due to age, providing more effect.
References:
1. Dworkin, R. H., Johnson, R. W., Breuer, J., et al. Recommendations for the Management of Herpes Zoster. Clinical Infectious Diseases. 2007; 44(1):S1–S26.
2. Shingrix approved in the US for prevention of shingles in adults aged 50 and over. 2017. https://www.gsk.com/en-gb/media/press-releases/shingrix-approved-in-the-us-for-prevention-of-shingles-in-adults-aged-50-and-over/
3. Shingles (Zoster): Questions and Answers Information about the disease and vaccine. http://www.immunize.org/catg.d/p4221.pdf
4. Immunization Schedules. 2017. https://www.cdc.gov/vaccines/schedules/hcp/imz/adult.html
5. Highlights of Prescribing Information. 2017. https://www.gsksource.com/pharma/content/dam/GlaxoSmithKline/US/en/Prescribing_Information/Shingrix/pdf/SHINGRIX.PDF