Varicella vaccination - the global experience

ABSTRACT

Introduction: Varicella, although a frequently benign childhood disease, nevertheless represents a considerable health burden. WHO recommends including varicella vaccines in universal routine vaccination programs, and maintaining coverage >80%. Many countries have successfully introduced varicella vaccination and have benefited from lower disease burden, but many others have not adopted the vaccine. Reasons include cost commitment for a ‘mild childhood disease’ or concerns that vaccination will shift varicella to older age groups or increase herpes zoster incidence.

Areas covered: This literature review summarizes the effectiveness and epidemiological impact of varicella immunization programs.

Expert commentary: Varicella vaccines are immunogenic with acceptable safety profiles. One and two dose schedules are highly effective against varicella and large reductions in disease incidence, particularly moderate-severe disease, have been widely reported. There is currently no evidence to suggest that the introduction of varicella vaccination results in a shift of varicella disease burden to older age groups. Although epidemiological studies have shown an increased incidence of herpes zoster since the vaccines were launched, there are many other contributing factors, and indeed, this secular trend was evident before their introduction. In conclusion, varicella vaccination easily fits into existing immunization programs and significantly reduces the often underestimated burden of varicella.

KEYWORDS:

• Varicella
• herpes zoster
• vaccines
• effectiveness
• immunization

Acknowledgments

The authors acknowledge Preethi Govindarajan (GSK, Bangalore, India) and Julia Donnelly (Freelancer for XPE Pharma and Science, Wavre, Belgium c/o GSK) for writing support; and Ashmita Ravishankar (GSK, Bangalore, India) and Adrian Kremer (XPE Pharma and Science, Wavre, Belgium c/o GSK) for editorial support and publication management. The authors would also like to thank Dr. Iris Depaz, Dr. Nicolas Praet, Dr. Christophe Tournay and Dr. Jennifer Cnops for their critical input in the paper.

Trademark

Varilrix and Priorix-Tetra are trademarks of the GSK group of companies.

Varivax and ProQuad are trademarks of Merck & Co. Inc., USA.

Declaration of interest

P Wutzler reports personal fees from the GSK group of companies and Sanofi Pasteur MSD for participating in advisory boards and payment for lecture fees. P Bonanni reports grants and personal fees from Pfizer, GSK groups of companies, Novartis and Sanofi Pasteur MSD. A Gershon reports service contracts (molecular VZV diagnosis for vaccine safety) for ad hoc consulting on VZV by Merck & Co, for serving as a chair on the data and safety monitoring board for the VZV vaccine by the GSK group of companies and receiving NIH research funding. M Safadi reports grants and personal fees from the GSK group of companies, Novartis Vaccines, Sanofi Pasteur MSD and Pfizer for research and speakers’ honoraria. G Casabona is an employee of the GSK group of companies and holds shares in the GSK group of companies. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Additional information

Funding

GlaxoSmithKline S.A. sponsored and funded this study and was involved in all stages of the study conduct and analysis and also took charge of all costs associated with the manuscript.