Estimating Neonatal Herpes Simplex Virus Incidence and Mortality Using Capture-recapture, Florida

BACKGROUND: Neonatal herpes simplex virus infection (nHSV) leads to severe morbidity and mortality, but national incidence is uncertain. Florida regulations require that healthcare providers report cases, and clinical laboratories report test results when herpes simplex virus (HSV) is detected. We estimated nHSV incidence using laboratory-confirmed provider-reported cases and electronic laboratory reports (ELR) stored separately from provider-reported cases. Mortality was estimated using provider-reported cases, ELR, and vital statistics death records. METHODS: For 2011-2017, we reviewed: provider-reported cases (infants ≤ 60 days of age with HSV infection confirmed by culture or polymerase chain reaction PCR), ELR of HSV-positive culture or PCR results in the same age group, and death certificates containing International Classification of Disease, Tenth Revision, codes for herpes infection: P35.2, B00.0-B00.9, and A60.0-A60.9. Provider-reported cases were matched against ELR reports. Death certificates were matched with provider and ELR reports. Chapman's capture-recapture method was used to estimate nHSV incidence and mortality. Mortality from all 3 sources was estimated using log-linear modeling. RESULTS: Providers reported 114 nHSV cases, and ELR identified 197 nHSV cases. Forty-six cases were common to both datasets, leaving 265 unique nHSV reports. Chapman's estimate suggests 483 (95% confidence interval CI, 383-634) nHSV cases occurred (31.5 infections per 100 000 live births). The nHSV deaths were reported by providers (n = 9), ELR (n = 18), and vital statistics (n = 31), totaling 34 unique reports. Log-linear modeling estimates 35.8 fatal cases occurred (95% CI, 34-40). CONCLUSIONS: Chapman's estimates using data collected over 7 years in Florida conclude nHSV infections occurred at a rate of 1 per 3000 live births.