As Herpes Zoster Incidence Increases, Treatment and Prevention Methods Are Essential

With research suggesting that herpes zoster has been on the rise in recent decades, disproportionately impacting women and elderly individuals, effective treatment and prevention options are essential. A recent review of the information was published in Infectious Disease Clinics of North America.

Treatment for herpes zoster can be approached either with antivirals or by treating the sequelae of the infection, according to the review authors. Antiviral therapy is indicated in patients who are either older than 50 years of age, have moderate-to-severe rash or pain, have non-truncal involvement, and are immunocompromised. If initiated within 72 hours of rash onset, antivirals can decrease the duration of vital shedding, new lesion formation, and the severity and duration of acute pain.

Hospitalization is not necessary in many cases, although the authors said it should be considered for closer monitoring and intravenous treatment in some cases. Specifically, it may be necessary in those who have received allogenic stem cell transplants, those with hematopoietic stem cell transplant with moderate to severe graft-versus-host disease, transplant recipients on aggressive anti-rejection therapy, anyone with suspected visceral dissemination, and individuals with herpes zoster or varicella zoster retinitis.

Acyclovir, famiciclovir, and valacyclovir are guanosine analogs that are able to inhibit varicella zoster virus DNA polymerase. In head-to-head trials, researchers have found no difference among acyclovir, famciclovir, and valacyclovir in treatment end points. The drugs also have similar adverse effect profiles, although ease of dosing, bioavailability, and cost should be considered when choosing between them.

Notably, cases of acyclovir-resistant varicella zoster virus have been reported in immunocompromised hosts, so resistance may be an issue if the lesions appear to be atypical and are not responding to antiviral therapy. If resistance is suspected, the patient should be tested for mutations in the thymidine kinase gene and switched to intravenous foscarnet or cidofovir, according to the review authors.

Other treatment approaches can include corticosteroids or analgesics to improve the pain associated with acute herpes zoster. When considering corticosteroids, the review authors said consideration should be given to relative contraindications, such as hypertension, diabetes, glaucoma, osteoporosis, or peptic ulcer disease. If used, the authors said steroids should always be used in conjunction with antivirals.

Mild pain associated with herpes zoster can be treated with analgesics such as acetaminophen and nonsteroidal anti-inflammatory drugs. These options are unlikely to provide much relief for postherpetic neuralgia, although the authors said they are the first-line agents for pain control in acute herpes zoster. Although opioids are not approved by the FDA for use in postherpetic neuralgia, they are currently considered third-line agents for symptom relief in combination with tramadol.

When considering prevention, there is currently 1 available live attenuated vaccine (Zostavax, Merck), for the prevention of shingles. According to the review, it is the same strain as the vaccine used for primary prevention of chickenpox, but at a 14 times higher dose. The researchers said there has been a poor uptake of this vaccine, with only 24% of US adults older than 60 years of age having received Zostavax in 2013. Although the proportion of the vaccinated population has increased, it is still below the Health People 2020 goal of 30%, according to the authors.

In 2017, officials with the FDA approved the zoster vaccine recombinant, adjuvanted (Shingrix, GlaxoSmithKline) for the prevention of herpes zoster in adults aged 50 years and older. Shingrix is a non-live, recombinant subunit vaccine given intramuscularly in 2 doses.

The approval was based on a phase 3 clinical trials that evaluated the vaccine's efficacy, safety and immunogenicity in more than 38,000 people. In a pooled analysis of these studies, Shingrix demonstrated efficacy against shingles greater than 90% across all age groups, as well as sustained efficacy over a follow-up period of 4 years. By preventing shingles, Shingrix also reduced the overall incidence of postherpetic neuralgia, a form of chronic nerve pain and the most common complication associated with shingles.

REFERENCE

John A, and Canaday D. Herpes zoster in the older adult. Infectious Disease Clinics of North America; December 1, 2020. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5724974/. Accessed March 12, 2021.