Neonatal Herpes Simplex Virus Infection

The Bottom Line: There are specific objective risk factors that significantly increase the likelihood of Neonatal Herpes Simplex Virus (HSV) infection in neonates. These factors include the presence of seizures, skin lesions, elevated alanine aminotransferase (ALT), low platelet count (thrombocytopenia), cerebrospinal fluid (CSF) pleocytosis, and the state of critical illness.
Objective: The study was designed to identify the specific clinical and laboratory characteristics of infants presenting with suspected infection that could help clinicians determine which individuals are truly at risk of having HSV.

Study Design: This was conducted as a retrospective case-control study.
Patient Population: The study focused on infants less than $42\,\text{days}$ of age who were undergoing evaluation for sepsis.
Statistical Analysis: Investigators used logistic regression to determine the factors associated with a positive HSV infection.
Group Categorization:
- Cases: $32$ infants who tested positive for HSV.
- Controls (Group 1): $64$ infants who tested negative for HSV.
- Controls (Group 2): $64$ infants who were evaluated for sepsis and did not have a positive HSV test (this group may or may not have undergone specific HSV testing, but were confirmed not to have a recorded positive result).

Thrombocytopenia (Low Platelets): Observed in $28\%$ of cases, compared to a range of $1.6\%$ to $3.1\%$ in control groups.
Skin Lesions: Observed in $56\%$ of cases, compared to a range of $7.8\%$ to $1.6\%$ in control groups.
Seizure Activity: Observed in $22\%$ of cases, compared to a stable frequency of $1.6\%$ to $1.6\%$ across control groups.
Elevated ALT: Observed in $31\%$ of cases, compared to a range of $6.3\%$ to $7.8\%$ in control groups.
CSF Pleocytosis: Observed in $34.4\%$ of cases, compared to a range of $13.1\%$ to $31.3\%$ in control groups.
Critical Illness: Observed in $31\%$ of cases, compared to a range of $15.6\%$ to $9.4\%$ in control groups.

Identifying Low-Risk Infants: A significant finding was the high sensitivity of these combined risk factors. Out of the $32$ cases of confirmed HSV, only $1$ infant presented without any of these identified risk factors.
Editor’s Warnings and Precautions: While this data provides a specific list of risk factors suggestive of HSV infection in ill children under $42\,\text{days}$ of age, the editors advise caution. It is considered prudent to be hesitant when using this specific data set to definitively rule out HSV infection until more valid evidence is gathered from larger, more robust data sets.
General Context: The data serves as a list of red flags for infants being evaluated for sepsis, rather than a definitive exclusion tool.