Vertical transmission risk: Which hepatitis viruses among the following are known to have mother-to-child (perinatal) transmission?

Introduction:
Vertical transmission affects neonatal outcomes and prevention strategies such as maternal screening, antiviral therapy, and immunoprophylaxis. Multiple hepatitis viruses can be transmitted perinatally under specific conditions.

Given Data / Assumptions:

• We consider perinatal transmission rates and mechanisms.
• HBV, HCV, and HDV are listed.
• HDV requires HBV for transmission and replication.

Concept / Approach:
HBV has significant perinatal transmission risk, especially with high maternal viral load and HBeAg positivity; immunoprophylaxis at birth is crucial. HCV vertical transmission occurs, with risk factors including high maternal viremia and HIV coinfection. HDV may be vertically transmitted when HBV is present, though efficiency varies by epidemiology.

Step-by-Step Solution:
Acknowledge strong perinatal risk for HBV and its prevention with HBIG plus vaccine. Recognize documented though lower-rate vertical transmission for HCV. Include HDV in contexts of maternal HBV coinfection. Choose the inclusive option covering all three viruses.

Verification / Alternative check:
Clinical guidelines address perinatal HBV prophylaxis; studies confirm measurable vertical HCV transmission; HDV follows HBV epidemiology.

Why Other Options Are Wrong:

• HBV / HCV alone: Incomplete; HDV can also be transmitted in HBV coinfection settings.
• None of these: Contradicted by established perinatal transmission data.

Common Pitfalls:
Assuming HDV cannot be vertically transmitted; while less frequent, it is possible when HBV is present.

Final Answer:
All of these can be transmitted vertically under the appropriate conditions.