Herpes Zoster Vaccine Is Safe, but Financial and Other Barriers Limit Its Use

Laurie Barclay, MD

May 04, 2010

May 4, 2010 — Herpes zoster vaccine is well tolerated in older, immunocompetent adults, according to the results of a randomized, placebo-controlled trial reported in the May 4 issue of the Annals of Internal Medicine. A second study in the same issue suggests that physicians' efforts to administer herpes zoster vaccine are hampered by financial and other barriers.

First Study: Simberkoff and Colleagues

"The herpes zoster vaccine is effective in preventing herpes zoster and postherpetic neuralgia in immunocompetent older adults," write Michael S. Simberkoff, MD, from New York University School of Medicine in New York, and colleagues from the Shingles Prevention Study Group. "However, its safety has not been described in depth."

The goal of this study was to evaluate local adverse effects and safety profiles of a single dose of herpes zoster vaccine vs placebo in immunocompetent older adults, both in the short term and in the long term. Participants at 22 US academic centers were enrolled from November 1998 to September 2001 and were observed through April 2004, with mean follow-up duration of 3.4 years.

The study sample consisted of 38,546 immunocompetent adults 60 years or older, including 6616 who were enrolled in a substudy of adverse events. The permutated block randomization scheme was generated by a Veterans Affairs Coordinating Center and stratified by site and age, and participants and follow-up evaluators were masked to treatment group. The main study endpoints were serious adverse events, rashes, and deaths in all participants, and inoculation-site events during the first 42 days after inoculation in substudy participants.

Serious adverse events after inoculation were reported in 255 participants who received vaccine (1.4%) and in 254 (1.4%) who received placebo. In the substudy, 1604 vaccine recipients (48%) and 539 placebo recipients (16%) reported local inoculation-site adverse effects.

Among the vaccine recipients reporting local adverse effects, 977 (56.6%) were 60 to 69 years old, and 627 (39.2%) were older than 70 years. Herpes zoster occurred after inoculation in 7 participants who received the vaccine and in 24 who received placebo. Vaccine and placebo recipients had similar rates of hospitalization or death during long-term follow-up.

Limitations of this study are lack of random selection of participants in the substudy and failure to confirm reported serious adverse events with medical record data in all cases.

"Our analyses showed that herpes zoster vaccine was well tolerated and safe in older immunocompetent adults," the study authors write. "There was a modest increase in the rate of acute inoculation-site events in vaccine recipients, but no increased risk for herpes zoster itself and no pattern suggesting any serious adverse events were causally related to vaccination. Given the substantial protection that herpes zoster vaccine provides against the occurrence and morbidity of herpes zoster and, specifically, postherpetic neuralgia, we believe that this safety profile supports the recommendation for routine use of herpes zoster vaccine in immunocompetent older adults, who are at increased risk for herpes zoster and its complications."

Second Study: Hurley and Colleagues

A second study, by Laura P. Hurley, MD, MPH, and colleagues, describes barriers to the use of herpes zoster vaccine, which is the most expensive vaccine recommended for older adults and the first vaccine to be reimbursed through Medicare Part D. From July to September 2008, the investigators conducted a national mail and Internet-based survey of general internists and family medicine physicians regarding current vaccination practices, knowledge of and practice regarding reimbursement, and barriers to vaccination.

For both specialties, response rates were 72%, with surveys completed by 301 general internists and 297 family medicine physicians. Methods for administering vaccine for physicians in both specialties included stocking and administering the vaccine in their offices (49%), having patients purchase the vaccine from a pharmacy and bring it to the office for administration (36%), and referring patients to a pharmacy for vaccine administration (33%).

Although 90% of providers strongly recommended influenza and pneumococcal vaccines, only 88% recommended herpes zoster vaccine, and only 41% strongly recommended it. Financial barriers were the most commonly reported barriers to herpes zoster vaccination for physicians in both specialties, but only 45% of providers surveyed knew that Medicare Part D reimburses for herpes zoster vaccine. Among respondents who started administering herpes zoster vaccine in their office, 12% stopped because of cost and reimbursement issues.

Limitations of this survey include reliance on provider report and lack of generalizability to all providers.

"Physicians are making efforts to provide herpes zoster vaccine but are hampered by barriers, particularly financial ones," the study authors write. "Efforts to facilitate the financing of herpes zoster vaccine could help increase its use."

Editorial: Comprehensive Approach Needed

In an accompanying editorial, James G. Donahue, DVM, PhD, and Edward A. Belongia, MD, from the Marshfield Clinic Research Foundation in Marshfield, Wisconsin, note that the United States is in dire need of a comprehensive approach to adult immunization.

"Vaccines have an important role in the prevention of serious illness in people of all ages, and it is time to reconsider the current system that focuses only on childhood vaccine delivery," Drs. Donahue and Belongia write. "A comprehensive adult immunization program would increase utilization not only of the herpes zoster vaccine but also all recommended adult vaccines and reduce the number of deaths and serious illnesses caused by vaccine-preventable diseases."

The Cooperative Studies Program, Department of Veterans Affairs, Office of Research and Development; grants from Merck to the Veterans Affairs Cooperative Studies Program; and the James R. and Jesse V. Scott Fund for Shingles Research supported the first study.

The US Centers for Disease Control and Prevention supported the second study. Disclosures of the study authors can be viewed here . The editorialists have disclosed no relevant financial relationships.

Ann Intern Med. 2010;152:545-554, 555-560, 609-611.

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