Which of the following vaccine should not be given during pregnancy ?
**Core Concept**
Live attenuated vaccines pose a risk of transmission of the vaccine strain to the fetus due to the presence of the virus in the maternal bloodstream. This is particularly concerning during pregnancy, where the fetus is immunologically immature and vulnerable to infections.
**Why the Correct Answer is Right**
The live attenuated measles, mumps, and rubella (MMR) vaccine is contraindicated in pregnancy due to the theoretical risk of transmission of the vaccine strain to the fetus. This risk is supported by studies demonstrating the presence of measles virus RNA in the placenta and fetal tissues after maternal immunization with the MMR vaccine. As a result, the Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists (ACOG) recommend avoiding the MMR vaccine during pregnancy.
**Why Each Wrong Option is Incorrect**
* **Option A:** Inactivated influenza vaccine (IIV) is recommended for pregnant women during the influenza season, as it does not pose a risk of transmission to the fetus.
* **Option B:** Tetanus toxoid-containing vaccines, such as Td and Tdap, are recommended for pregnant women to prevent tetanus and pertussis, and are not contraindicated during pregnancy.
* **Option D:** Inactivated poliovirus vaccine (IPV) is also recommended for pregnant women and is not contraindicated during pregnancy.
**Clinical Pearl / High-Yield Fact**
Pregnant women should receive inactivated vaccines, such as influenza and Tdap, to protect against vaccine-preventable diseases, while live attenuated vaccines, like MMR, should be avoided due to the risk of transmission to the fetus.
**Correct Answer:** . Measles, mumps, and rubella (MMR) vaccine