Background The epidemiology of neonatal herpes infection (nHSV) is changing as herpes simplex virus type 1 (HSV-1) is an increasingly common cause of genital herpes. Few sources of population-based data for nHSV exist; nHSV has been a notifiable disease in New York City (NYC) since 2006.

Methods To compare the clinical and demographic characteristics of nHSV due to HSV-1 and herpes simplex virus type 2 (HSV-2), we used standard case investigation forms to abstract infant inpatient/outpatient medical records, and maternal labour and delivery records for babies ≤ 60 days of age diagnosed with laboratory-confirmed herpes infection and reported in NYC during 2006–2012. Disease syndromes were grouped as invasive (disseminated/central nervous system infection/death) versus localised (skin/eye/mucous membrane infection,). Cases lacking liver function test results, or lumbar puncture were excluded from analyses of disease syndrome. Bivariate analyses compared clinical and demographic characteristics by viral type.

Results There were 91 cases reported (HSV-1, 40; HSV-2, 36; untyped, 15). Among 76 cases with viral typing, the majority (53%; 40/76) were HSV-1. There were no statistically significant differences by viral type for any variables examined: age ≤ 7 days at presentation (HSV-1, 59% versus HSV-2, 41%), fever (HSV-1, 38% versus HSV-2, 46%), vesicles (HSV-1, 46% versus HSV-2, 53%), invasive disease (HSV-1, 53% versus HSV-2, 70%), case fatality rate (HSV-1, 18% versus HSV-2, 19%), maternal history of genital herpes (HSV-1, 20% versus HSV-2, 20%), maternal genital lesions at delivery (HSV-1, 8% versus HSV-2, 3%), vaginal delivery (HSV-1, 69% versus HSV-2, 61%), white non-Hispanic maternal race/ethnicity (HSV-1, 26% versus HSV-2, 12%), maternal age < 20 (HSV-1, 15% versus HSV-2, 27%).

Conclusions Neonatal herpes infections due to HSV-1 and HSV-2 have a similar presentation, and death rate. To prevent nHSV, candidate HSV vaccines will need to protect against HSV-1, as well as HSV-2 infection in women.