The Safety Profile Of Varicella Vaccine:

SUPPLEMENT ARTICLE

The Safety Profile of Varicella Vaccine: A 10-Year Review
Susan A. Galea,1 Ann Sweet,1 Paul Beninger,1 Sharon P. Steinberg,2 Philip S. LaRussa,2 Anne A. Gershon,2 and Robert G. Sharrar1
1

Merck Research Laboratories, Clinical Risk Management and Safety Surveillance, North Wales, Pennsylvania; 2Columbia University College of Physicians and Surgeons, New York, New YorkVarivax (varicella virus vaccine live [Oka/Merck]; Merck), a live attenuated varicella vaccine, is indicated for vaccination against varicella in appropriate individuals 12 months of age. The 10-year safety profile for Varivax is described using data submitted to Merck from routine global postmarketing surveillance, combined with information from a Varicella Zoster Virus Identification Program,which uses polymerase chain reaction (PCR) analysis to identify the presence and strain of VZV in selected specimens. There were 16,683 reports worldwide voluntarily submitted to Merck, for an overall reporting rate of 3.4 reports/10,000 doses of vaccine distributed. PCR analysis of vesicular rashes that occurred within the first 2 weeks after vaccination was more likely to identify wild-typevaricella-zoster virus (VZV), whereas the presence of Oka VZV was generally associated with vesicular rashes that occurred 15–42 days after vaccination. Reports of breakthrough varicella that occurred 142 days after vaccination were associated with wild-type VZV. Among 697 herpes zoster reports, PCR analysis identified Oka VZV in 57 reports and wild-type VZV in 38 reports. There were no primaryneurologic adverse events associated with Oka VZV. Secondary transmission of Oka VZV from vaccine recipients with postvaccination vesicular rashes was identified in 3 susceptible household contacts. Disseminated Oka VZV was identified in 6 immunocompromised patients and 1 patient with Down syndrome. This review has shown that the vaccine is generally safe and well tolerated. Varivax (varicella virusvaccine live [Oka/Merck]; Merck), a live attenuated viral vaccine, became commercially available in the United States on 1 May 1995. The vaccine has been marketed worldwide in 46 countries, with ∼55 million doses distributed. In the present article, we describe the safety profile of varicella vaccine by use of spontaneous postmarketing adverse experience (AE) reports submitted to Merck, together withresults from the Varicella Zoster Virus Identification Program (VZVIP) during the first 10 years of marketing experience since the licensure of Varivax. METHODS Postmarketing surveillance. The postmarketing reporting system for AEs is a passive, spontaneous, voluntary, incomplete reporting system. Merck’s Worldwide Adverse Experience System database contains records of AEs spontaneously reported tothe company by health care professionals and consumers, as well as case reports from the published literature. All reported AEs temporally related to the administration of a vaccine are added to the database without regard to the likelihood of a causal relationship and are coded in the terminology used by the reporter. Definitions. The following case definitions were used to categorize AE data foranalysis. A breakthrough

Downloaded from http://jid.oxfordjournals.org/ by guest on October 7, 2012

Potential conflicts of interest: S.A.G., A.S., P.B., and R.G.S. are salaried employees of Merck and possess stock and stock options in the company. A.A.G. lectures and consults on varicella-zoster virus vaccines for Merck and GlaxoSmithKline when invited and receives research support fromMerck. Additionally, P.S.L., S.P.S., and A.A.G. are in a contractual relationship with Merck through the Varicella Zoster Virus Identification Program. Financial support: supplement sponsorship is detailed in the Acknowledgments. Reprints or correspondence: Susan A. Galea, Merck Research Laboratories, Clinical Risk Management and Safety Surveillance, UG3C-54, PO Box 1000, North Wales, PA 19454-1099...