to the editor: Chickenpox incidence rates have decreased substantially across the United States since the introduction of the varicella vaccine and subsequent school immunization requirements in many states.1 This does not mean, however, that the risk of adverse outcomes from varicella infection has disappeared. A recent death from congenital varicella highlights the need for physicians and public health workers to maintain awareness of the threat that varicella poses to pregnant women and their fetuses.
On May 10, 2011, a male infant was born at 34 to 35 weeks' gestation to a 22-year-old mother who reported in April that she had had varicella in the first trimester of the pregnancy. Because of intrauterine growth restriction, the infant's birth weight was 870 g (1 lb, 15 oz). He also had several other conditions consistent with congenital varicella syndrome, including club foot, liver calcifications, dermatome scarring of the face, and microcephaly with ventriculomegaly. Life support was removed, and the infant died on May 13, 2011.
The mother was from Mexico and had not received varicella vaccine, nor had she had the infection prior to her pregnancy. In April 2011, she reported having chickenpox in January along with a child in her household. A varicella immunoglobulin M antibody assay performed in April was positive. Neither the mother nor her child had sought medical care, and their infections were not reported to the health department by a school or employer.
This case highlights several important considerations. First, the risk of congenital varicella remains, although the incidence and case fatality rates continue to decline.2 Usually when a vaccine is introduced, the burden of disease shifts from a younger population to an older population. Second, even though use of varicella vaccine is increasing across the country, adults and adolescents may still be at risk because they are typically not targeted by immunization campaigns. Finally, women from tropical areas such as Central or South America may reach adulthood without having had chickenpox, leaving them vulnerable to infection during pregnancy.3
Health care professionals need to be aware of the risks of congenital varicella and screen women of childbearing age for immunity to varicella, especially those from Latin America. Screening should begin by asking about the patient's history of varicella infection or vaccination. Those who are unsure or not immune should be vaccinated if they are not pregnant; in those who are pregnant, a titer should be obtained, and the patient should be counseled to avoid contact with persons who have chickenpox or shingles, and to inform her obstetrician immediately if exposure or symptoms occur.4 Additionally, susceptible pregnant women need to be informed of the risks of congenital varicella, so that they are aware of the importance of reporting such exposures to their physicians for possible intervention (administration of varicella zoster immune globulin, or watchful waiting and administration of acyclovir [Zovirax] if symptoms develop).3