Update on neonatal herpes simplex epidemiology in the Netherlands

Background: This article provides an update on the incidence of neonatal herpes, guideline adherence by health care professionals (HCP) and trends in genital herpes simplex virus (HSV) infection during pregnancy in the Netherlands. Methods: Questionnaires were sent to all hospitals inquiring about numbers and characteristics of neonatal and maternal HSV infections, and guideline adherence between 2012 and 2015. Longitudinal trends were investigated from 1999 onward using survey data and Perinatal Registry of the Netherlands data (Perined). Trends were smoothed with Poisson regression splines. Risk indicators for neonatal and maternal HSV infections were examined with Poisson regression analyses. Results: Neonatal herpes incidence was 4.8/100,000 live births based on survey data (2012-2015) and 3.4/100,000 based on Perined (2012-2014). Mortality rate was 23% (7/30). Neonatal herpes incidence increased slightly over time as did the prevalence of genital HSV infection among pregnant women. Non-Western ethnicity (Rate Ratio: 1.9; 95% confidence interval: 1.5-2.5) and age <20 years (Rate Ratio: 2.3; 95% confidence interval: 1.2-4.7) were associated with genital herpes during pregnancy. In Perined, none of the neonatal herpes cases had a mother diagnosed with an active genital herpes infection during pregnancy. Preventive measures to reduce vertical herpes transmission (such as cesarean section) were less commonly reported by HCP in 2012-2015 compared with 2006-2011. Conclusions: Neonatal herpes incidence in the Netherlands slowly increased over the last 15 years. An increased genital HSV prevalence during pregnancy or, to lower extent, the decreased guideline adherence by HCP may be responsible. A rise in asymptomatic maternal HSV shedding is also plausible, emphasizing the challenges in preventing neonatal herpes.