Varicella vaccine

Zostavax : a subcutaneous vaccine for the prevention of herpes zoster

INTRODUCTION

Herpes zoster (HZ) occurs as a reactivation of dormant varicella zoster virus (VZV), and occurs more frequently in the aging population or the immunocompromised due to waning cell-mediated immunity. Up to 1 million cases of HZ are reported annually in the USA with an estimated 10 - 30% of the population being affected by shingles in their lifetime. HZ is a debilitating illness, and while mortality is low, morbidity remains a significant cause for concern with prevention efforts aimed at reducing VZV reactivation and its complications. The HZ vaccine was approved by the US Food and Drug Administration for individuals aged 50-years or older. However, the Center for Disease Control and Prevention's Advisory Committee for Immunization Practices recommends the vaccine in individuals aged 60-years or older.

AREAS COVERED

Recent literature investigating the efficacy and indications of live attenuated zoster vaccine.

EXPERT OPINION

Live attenuated zoster vaccine is safe and efficacious in preventing HZ and decreasing the morbidity associated with postherpetic neuralgia. The vaccine is FDA approved in individuals aged 50-years or older but further studies are warranted to investigate the vaccine's efficacy in immunosuppressed and immunocompromised patients.

Risk factors for breakthrough varicella in healthy children

AIM

To evaluate the risk factors for breakthrough varicella in a follow up study of a cohort of 181 healthy children immunised when aged 9-24 months with a reformulated Oka strain varicella vaccine (SmithKline Beecham Biologicals/Oka).

DESIGN

The children were randomised in a double blind manner into one of four groups to receive one of two production lot vaccine batches, at two different titres (high titre, 10(3.9) and 10(4.0) plaque forming units (pfu); low titre (heat exposed), 10(2.7) and 10(2.8) pfu). The overall seroconversion rate after immunisation was 99%.

RESULTS

One hundred and sixty-eight patients were available for review after a mean (SD) follow up of 35 (9) months after vaccination. Multivariate analysis indicated that risk factors for breakthrough varicella were household contact with varicella (adjusted odds ratio (OR), 19.89; 95% confidence interval (CI), 18.39 to 21.39), vaccination age of < or = 14 months (adjusted OR, 2.30; 95% CI, 1.69 to 2.90), and receiving low titre (10(2.7) pfu) vaccine (adjusted OR, 2.13; 95% CI, 1.54 to 2.73). All children who developed breakthrough varicella, had a modified varicella illness, except for three, all of whom had received low titre vaccine.

CONCLUSION

The identification of young immunisation age (< or = 14 months) and low titre vaccine as risk factors for breakthrough varicella have important implications for the implementation of varicella vaccination programmes in healthy children.

New aspects of exanthematous diseases of childhood

The childhood exanthems include a spectrum of common and uncommon disorders caused by a variety of pathogens. In this article, timely issues relating to immunization for measles and varicella are discussed. Recently reported exanthematous illnesses, including papular-purpuric gloves and socks syndrome, unilateral laterothoracic exanthem, and eruptive pseudo-angiomatosis, are described. The current research and debate about bacterial toxins as the cause of Kawasaki syndrome are presented.

New varicella vaccines

The live attenuated varicella vaccine, which is available for the prevention of chickenpox, was produced by a classic technology that also has been used for polio, measles, mumps, and rubella vaccines. There are many newer technologies that have been applied to the research and development of other vaccines. Each of these other approaches offers potential advantages and disadvantages relative to the current varicella vaccine.