Pregnant women with fewer sexual partners were observed to be increasingly seronegative for herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), according to research published in Clinical Infectious Diseases. This increased seronegativity means these women are a greater risk for HSV-1 or HSV-2 for the first time during pregnancy, which increases the risk for transmission to their neonates.
Using data from the National Health and Nutritional Examination Surveys, several study objectives were investigated. Levels of HSV-1 and HSV-2 seroprevalence among pregnant women age 20 to 39 years were estimated, changes in seroprevalence were assessed, and levels of HSV seroprevalence between pregnant women and sexually active non-pregnant women were compared.
Between 1999 and 2014, HSV-1 seroprevalence among pregnant women was 59.3%, while seroprevalence of HSV-2 was 21.1% and seronegativity for HSV was 30.6%. Seroprevalence remained stable in this population between 1999 and 2006 and 2007 and 2014, but seronegativity for both HSV-1 and HSV-2 among pregnant women with 3 or fewer lifetime sexual partners increased from 35.6% to 51.4% (P <.05). The increased seronegativity in this group represented approximately 40% of all pregnant women sampled.
The National Health and Nutritional Examination Surveys database, however, does not contain information on women age 14 to 19 years of age and therefore the analysis could not address the declines of HSV-1 and HSV-2 among this population. Distinctions between genital and oral herpes were also not possible as serologic testing was used in the database. Finally, data were also not available to investigate trends in seroprevalence between 2007 and 2014 among women with 3 or fewer sexual partners by race/ethnicity or other behavioral and demographic factors.
The results do highlight that a growing number of pregnant women in the United States lack HSV-1 and HSV-2 antibodies and are therefore at risk for acquiring the infection for the first time during pregnancy. Currently, HSV screening of asymptomatic pregnant women is not recommended, but several strategies have been proposed in the literature. Because of the high risk for neonatal transmission from a primary infection near delivery, investigators warn of the need for further research into prevention strategies against HSV acquisition and neonatal transmission in this group.
Patton M, Bernstein K, Liu G, Zaidi A, Markowitz L. Seroprevalence of herpes simplex virus types 1 and 2 among pregnant women and sexually active, non-pregnant women in the United States [published online April 16, 2018]. Clin Infect Dis. doi:10.1093/cid/ciy318