Which vaccine is contraindicated in pregnant women?

The live attenuated influenza vaccine is contraindicated in pregnant women primarily because it contains live, attenuated viruses that can potentially pose a risk to the developing fetus. During pregnancy, a woman's immune system is altered, which could allow the virus to replicate in an unintended way, potentially leading to complications. In contrast, both the Tdap vaccine and the inactivated flu vaccine are considered safe and are recommended for use during pregnancy. The Tdap vaccine is particularly important as it helps protect both the mother and the newborn from pertussis, and the inactivated flu vaccine is recommended to help guard against influenza-related complications during pregnancy. Pneumococcal vaccines are also safe during pregnancy and can help prevent serious infections. Therefore, the live attenuated influenza vaccine is the only option that poses a risk and is contraindicated for pregnant women.