Which vaccine is not recommended during pregnancy?

The human papillomavirus vaccine (HPV) is not recommended during pregnancy because it is a non-live vaccine designed to protect against certain strains of HPV that are associated with cervical and other cancers. While there is no evidence that the HPV vaccine is harmful during pregnancy, studies have not been conducted to establish its safety for pregnant women and their developing fetuses. As a precautionary measure, vaccination is typically postponed until after pregnancy.

In contrast, the inactivated influenza vaccine is safe and recommended during pregnancy to protect both the mother and her developing baby from influenza. The Tdap vaccine is also recommended during pregnancy to provide protection against tetanus, diphtheria, and pertussis for the mother and to boost the baby's immune response after birth. Additionally, the hepatitis B vaccine is advised during pregnancy if the mother is at risk of infection because it can help prevent transmission of the virus to the newborn. Hence, the HPV vaccine stands out as not recommended during pregnancy due to the lack of safety data in this specific population.