Mothers of Herpes Simplex Virus-infected newborn babies in Australia are four times more likely to be young women aged less than 20 years of age, a University of Sydney study reveals.

Neonatal Herpes Simplex Virus (HSV) infection is a rare but serious condition that can present with sores and lesions to the skin, eyes, and/or mouth, encephalitis, or disseminated infection affecting multiple glands and organs.

“Neonatal HSV infection is usually acquired during delivery following maternal genital HSV infection, but can also be acquired post-natally from an infected contact,” says the study’s lead author,University of Sydney Professor of Paediatric Infectious Diseases, Dr Cheryl Jones.

“Without antiviral therapy, death or handicap is almost inevitable after disseminated or central nervous system (CNS) disease.”

Though rare, HSV infection in newborns is now more common in Australia than other serious conditions passed from mother to child, such as congenital rubella, congenital syphilis, and perinatal human immunodeficiency virus (HIV).

Underlining the lethal nature of neonatal HSV-infection, the 15 year longitudinal population-based surveillance University of Sydney study reveals that although mortality has fallen in recent years, 19 per cent of HSV-infected neonates died in a study population of 131 cases.

Published in the latest issue of Clinical Infectious Diseases, the study confirms international research showing that HSV-1 has replaced HSV-2 as the leading cause of neonatal HSV disease.

“In the past, HSV-1 was typically associated with cold sores, whereas HSV-2 was the main cause of genital herpes,” says Dr Jones.

“However, more recent research shows an increase in genital herpes caused by HSV-1 in Australia, the United States, and elsewhere.

“This increase has been most marked in young women and is consistent with our findings of an overrepresentation of adolescent mothers in this study.

“The reasons for this increase are unknown but preventive efforts should include increasing adolescent awareness of sexually transmitted infections like HSV.”

Herpes simplex virus 1 and 2 (HSV-1 and HSV-2), also known as human herpesvirus 1 and 2 (HHV-1 and HHV-2), are two members of the herpesvirus family, Herpesviridae, that infect humans.

Both HSV-1 (which produces most cold sores) and HSV-2 (which produces most genital herpes) are ubiquitous and contagious.

They can be spread by contact with herpes lesions when an infected person is producing and shedding the virus. Herpes simplex can be also spread through contact with saliva, such as sharing drinks.

Key findings from the study:

  • The 15-year study identified 131 cases of neonatal HSV infection.
  • The reported incidence of neonatal HSV infection was stable over this period, but there was an increased rate of neonatal HSV-1 disease.
  • There was a high incidence in young mothers (< 20 years of age) in this series compared to Australian birth record data.
  • Significantly reduced mortality was observed in the latter part of the study but twenty four (24) children (19 per cent) had died from HSV-infection despite the availability of antiviral agents
  • HSV-infected neonates were more likely to be low (less than 2500 grams) to very low birth weight (less than 1500 grams), pre-term (less than 37 weeks), or very pre-term (less than 28 weeks).
  • One-third of the study’s HSV-infected infants were born by caesarian delivery, which has been reported to reduce rates of neonatal HSV infection. However the current study confirms that caesarian delivery does not eliminate neonatal HSV disease.

The study was contacted through the Australian Paediatric Surveillance Unit through notifications by paediatricians around the country and highlights the importance of national longitudinal studies of rare but medically important conditions. It is the largest and the only prospective series from the Southern Hemisphere.

(Source: The University of Sydney)