Which infectious diseases should be avoided by a pregnant healthcare professional who lacks immunity?

• A. Measles or rubella
• B. Coronavirus disease 2019 (COVID-19)
• C. Hepatitis B (HBV)
• D. Influenza

Answer: (A)

The main idea is to protect a pregnant healthcare worker from infections that can harm the fetus when immunity is lacking. Measles and rubella are especially risky during pregnancy because rubella infection can cause congenital rubella syndrome with serious fetal defects, and measles can lead to severe maternal illness and miscarriage. There is no safe, effective treatment to prevent fetal harm after exposure to these viruses, and the rubella component uses a live vaccine that is contraindicated during pregnancy, so immunity should be established before conception. If a nonimmune pregnant worker is exposed or at risk, the safest approach is to avoid contact with known cases and be reassigned or take steps to minimize exposure until immunity can be ensured after delivery.

In contrast, the other infections listed are managed through vaccination and protective measures that do not require inherently avoiding pregnancy work duties. Vaccines for influenza and COVID-19 are recommended during pregnancy, and hepatitis B vaccination is available, so exposure can be mitigated through immunization and standard precautions rather than avoidance.