Which of the following vaccines is safe during pregnancy?

Vaccination during pregnancy is guided by safety for both the mother and the developing fetus, as well as the ability to provide passive immunity to the newborn. Inactivated vaccines are generally safe in pregnancy, while live attenuated vaccines are contraindicated due to potential risk of fetal infection. Certain vaccines are specifically recommended during pregnancy to protect against serious maternal and neonatal infections. Understanding which vaccines are safe is essential for prenatal preventive care. Rationale: A. Intranasal influenza vaccine is a live attenuated vaccine and is generally contraindicated during pregnancy due to theoretical risks to the fetus. Although influenza vaccination is recommended in pregnancy, it must be administered in the inactivated injectable form rather than the intranasal version. The live formulation poses safety concerns and is avoided in pregnant patients. B. Tetanus, Diphtheria and Pertussis (Tdap) vaccine is safe and recommended during pregnancy, typically administered during each pregnancy regardless of prior immunization history. It helps protect the newborn from pertussis (whooping cough) through passive antibody transfer. This maternal immunization significantly reduces the risk of severe neonatal respiratory infection in early life. C. Measles, Mumps, and Rubella (MMR) vaccine is a live attenuated vaccine and is contraindicated during pregnancy due to potential risk of fetal infection. It is recommended to be given before conception or postpartum if immunity is lacking. Administration during pregnancy is avoided to prevent theoretical teratogenic effects. D. Varicella vaccine is also a live attenuated vaccine and is contraindicated during pregnancy. Exposure to the vaccine strain poses a potential risk to the fetus, so it should be administered prior to pregnancy or after delivery if needed. Pregnant patients who are non-immune are instead managed with post-exposure prophylaxis if exposed to the virus.