by Michael Smith
It’s a classic good-news, bad-news story.
The vaccine against shingles, already shown to be effective, is both safe and well-tolerated, researchers found after following more than 38,000 participants in the randomized trial that led to the 2006 approval of the vaccine.
On the other hand, few people are getting the vaccine, and for a variety of reasons — including its cost — researchers noted in a separate study. Both analyses appear in the May 4 issue of the Annals of Internal Medicine.
The findings highlight the lack of a comprehensive approach to adult vaccination in the U.S., according to James Donahue, DVM, PhD, and Edward Belongia, MD, both of the Marshfield Clinic Research Foundation in Marshfield, Wis.
In an editorial accompanying the two studies, they argued that such a broad approach should address vaccine financing and delivery, coverage levels, surveillance of vaccine-preventable diseases, vaccine safety, and logistical barriers.
The vaccine against herpes zoster and postherpetic neuralgia was shown to be effective in large randomized placebo-controlled trial, but its long-term safety had not been studied, according to Michael Simberkoff, MD, of Veterans Affairs New York Harbor Healthcare System in New York City, and colleagues.
So the researchers followed 38,546 adults ages 60 or older during the clinical trial of the vaccine from November 1998 to September 2001, then followed them for an average of 3.4 years through April 2004. The analysis included 6,616 who participated in an adverse events substudy.
The study looked at serious adverse events and rashes in all participants and injection-site events in the substudy participants during the first 42 days after inoculation.
After that, all participants were monitored for vaccination-related, serious adverse events and deaths, and inpatient care was monitored in substudy participants.
* Serious adverse events after inoculation were rare and evenly distributed between vaccine and placebo recipients — 255 vaccine recipients and 254 placebo recipients reported such an event.
* In the substudy, local site reactions were seen in almost half of the vaccine recipients — 1,604 or 48% — compared with 539 or 16% of those who got placebo.
* After inoculation, herpes zoster occurred in seven vaccine recipients and 24 participants who got placebo.
* Rates of inpatient care or death did not differ between vaccine and placebo recipients over an average of 3.39 years of follow-up.
Simberkoff and colleagues cautioned that adverse events substudy was not randomized. As well, they noted, not all reported serious adverse events were confirmed with medical data.
Although the vaccine was approved in 2006 and recommended in 2008 by the Advisory Committee on Immunization Practices for all adults over 60, the use of the vaccine has been limited, according to Laura Hurley, MD, of Wellington Webb Center for Primary Care in Denver, and colleagues.
To find out why, the researchers surveyed nearly 600 internists and family medicine physicians. They found:
* More general internists than family medicine physicians thought that more than half of their patients were eligible for the vaccine — 39% versus 13%, a difference that was significant at P<0.001.
* In both specialties, 49% of doctors stocked and administered the vaccine in their offices, while 36% sent patients to a pharmacy to buy the vaccine and bring it back to the office for administration, and 34% referred patients to a pharmacy for the shot.
* While 88% said they recommend the vaccine, only 41% strongly recommend it, compared with more than 90% who strongly recommend influenza and pneumococcal vaccines.
* The most frequently reported barriers to vaccination were financial: The vaccine costs about $200 and only 45% of respondents knew that the vaccination is reimbursed through Medicare Part D.
* Of respondents who began giving the vaccine, 12% said they stopped because of cost and reimbursement issues.
Hurley and colleagues cautioned that the survey relies on reported — but not observed — practice. As well, they said, those who answered the survey may not be representative of all healthcare providers.
The cost of the vaccine is “significant,” said Len Horovitz, MD, of Lenox Hill Hospital in New York City, who was not involved in either study.
“But the cost of treating postherpetic neuralgia is far more,” he told MedPage Today in an e-mail.
Michael Smith is a MedPage Today North American Correspondent.