Population-based surveillance for neonatal herpes in New York City, April 2006-September 2010

Population-based data for neonatal herpes simplex virus (HSV) infection are needed to describe disease burden and to develop and evaluate prevention strategies.

From April 2006 to September 2010, routine population-based surveillance was conducted using mandated provider and laboratory reports of neonatal HSV diagnoses and test results for New York City resident infants aged ≤60 days. Case investigations, including provider interviews and review of infant and maternal medical charts and vital records, were performed. Hospital discharge data were analyzed and compared with surveillance data findings.

Between April 2006 and September 2010, New York City neonatal HSV surveillance detected 76 cases, for an average incidence of 13.3/100,000 (1/7519) live births. Median annual incidence of neonatal HSV estimated from administrative data for 1997 to 2008 was 11.8/100,000. Among surveillance cases, 90.8% (69/76) were laboratory confirmed. Among these, 40.6% (28/69) were HSV-1; 39.1% (27/69) were HSV-2; and 20.3% (14/69) were untyped. The overall case-fatality rate was 17.1% (13/76). Five cases were detected among infants aged >42 days. In all, 80% (20/25) of the case-infants delivered by cesarean section were known to have obstetric interventions that could have increased risk of neonatal HSV transmission to the infant before delivery. Over half (68%, or 52/76) of all cases lacked timely or ideal diagnostics or treatment.

Administrative data may be an adequate and relatively inexpensive source for assessing neonatal HSV burden, although they lack the detail and timeliness of surveillance. Prevention strategies should address HSV-1. Incubation periods might be longer than expected for neonatal HSV. Cesarean delivery might not be protective if preceded by invasive procedures. Provider education is needed to raise awareness of neonatal HSV and to assure appropriate testing and treatment.