Increasingly, there is interest in developing a vaccine that would prevent additional outbreaks of HSV among individuals who are already positive for HSV. The vaccine would presumably boost the patient’s immunity to prevent subsequent outbreaks.
The rationale behind this approach to vaccination is supported by the experience with the herpes zoster vaccine.
The shingles vaccine is actually a concentrated form of the vaccine given to children for the prevention of chicken pox. In the original trials for the vaccine, all subjects were age 60 or older. Subjects received either active vaccine or placebo. There was a 51 percent reduction overall in the incidence of shingles among those who received the active vaccine. Efficacy was highest among those in their 60s—with about a 60 percent reduction in the incidence of shingles among those in their 60s.
These findings would seem to support vaccination in younger elderly patients. For one, the risk of developing shingles increases with age. Furthermore, the vaccine seems to be potentially more effective in younger patients. Overall, there was a 2/3 reduction in the incidence of post-herpetic neuralgia among those subjects who received the vaccination but nonetheless developed shingles.
A subsequent study enrolled patients in their 50s and determined that the efficacy rate of the vaccine was about 70 percent. The vaccine (Zostavax, Merck and Co.) received FDA approval for use in individuals 50 or older.
When to Vaccinate
The average age of patients presenting in Dr. Trying’s office with shingles is 51. This suggests that patients who receive the vaccination upon turning 50 may significantly reduce their risk for developing shingles. Increased age is a known risk factor for developing shingles. Although stress has frequently been identified as a risk factor, it appears that only significant, acute stress, such as the loss of a loved one, may be associated with shingles outbreak. Most recently, family history of shingles has emerged as a significant risk factor for developing shingles. Having a first-degree relative with shingles may double an individual’s risk for developing shingles.
Vaccination is not recommended for an individual who has recently had shingles. However, individuals who had shingles some time in the past (approximately a decade or so), vaccination may prevent re-emergence of shingles.
Finally, patient recollection of a personal history of chicken pox is rarely reliable. Many individuals simply do not recall having chicken pox as children. Furthermore, many sero-positive patients say that their parents never acknowledged that the patient had chicken pox. Importantly, patients do not require an antibody test prior to receiving the VZV vaccine. Cost of the vaccine, which may not be covered by third-party payors, can remain a limiting factor.