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December 11, 1996

Unintentional Administration of Varicella Virus Vaccine—United States, 1996

JAMA. 1996;276(22):1792. doi:10.1001/jama.1996.03540220016009

SINCE JUNE 1995, seven separate cases of unintentional administration of varicella virus vaccine (Varivax®*) to pregnant women have been reported in the United States to the Varivax® Pregnancy Registry. All seven women had household exposure to varicella, and varicella zoster immune globulin (VZIG) prophylaxis was indicated. However, Varivax® was administered unintentionally instead of VZIG to these women. One of the women received five times the recommended dose of vaccine. All had negative histories for varicella, and the status of their immunity to varicella before receiving the vaccine was not reported to the registry. Gestational age at vaccination ranged from 6 to 31 weeks; four of the seven pregnancies were <20 weeks' gestation. Two of these women have since delivered healthy infants; pregnancy outcomes are pending for five women.

Reported by: JM Manson, PhD, RG Sharrar, MD, Merck Research Laboratories, Worldwide Product Safety and