Congenital infection and newborn prophylaxis

Synopsis

Recognise congenital infection patterns, test within pathogen-specific diagnostic windows, deliver time-critical HIV and hepatitis B prophylaxis, treat neonatal HSV and syphilis promptly, and coordinate maternal, infant and public-health follow-up.

• Congenital infection crosses the placenta; perinatal infection is acquired around delivery. Timing determines phenotype, tests and prevention.
• Common patterns overlap: growth restriction, microcephaly, petechiae or blueberry-muffin lesions, jaundice, hepatosplenomegaly, eye disease, intracranial abnormality and hearing loss.
• Do not order an indiscriminate TORCH screen. Use maternal history, examination and organ pattern to select pathogen-specific PCR, serology, culture and imaging.
• For congenital CMV, test saliva PCR and confirm a positive result with urine PCR within 21 days of birth; after that, postnatal acquisition becomes difficult to distinguish.
• HIV prophylaxis begins as soon as possible, and no later than 4 hours. BHIVA uses 2 weeks of zidovudine alone for low-risk infants; standard high-risk combination prophylaxis is zidovudine plus lamivudine for 4 weeks with nevirapine for 2 weeks, using Appendix 4 doses.
• Follow the current BHIVA infant virological-testing schedule; antibody testing alone cannot diagnose HIV in a young exposed infant because maternal antibody persists.
• For maternal hepatitis B, give monovalent hepatitis B vaccine within 24 hours and add HBIG at a separate site for high-risk exposure, then complete the current selective neonatal schedule.
• The post-2025 hepatitis B schedule is birth and 4-week monovalent doses, routine hexavalent vaccine at 8, 12 and 16 weeks, an 18-month dose, and HBsAg testing at 12–18 months; verify current UKHSA updates.
• Suspected neonatal HSV requires IV aciclovir 20 mg/kg every 8 hours: 14 days for skin, eye and mouth disease and 21 days for CNS or disseminated disease, with specialist confirmation tests.
• Congenital syphilis prevention depends on adequate maternal penicillin completed at least 4 weeks before delivery; at-risk infants need examination, serology, CSF and treatment through BASHH or specialist pathways.
• Symptomatic congenital CMV, especially CNS or moderate-to-severe disease, may benefit from 6 months of valganciclovir started in the first month after specialist assessment, with blood-count, liver and renal monitoring.
• Every exposed infant needs closed-loop follow-up: medicines, PCR or serology schedule, hearing and eye assessment, immunisation, family testing and safeguarding or public-health communication.