A nurse is caring for a client who is at 30 weeks of gestation. The nurse should plan to immunize the client with which of the following vaccines?

Choice A rationale Diphtheria-acellular pertussis (Tdap) vaccine is recommended for pregnant clients during the third trimester, specifically between 27 and 36 weeks of gestation. This timing optimizes the transfer of maternal antibodies to the fetus, providing passive immunity against pertussis (whooping cough) in the newborn during their vulnerable early months, before they are old enough to receive their own vaccinations. Choice B rationale Inactivated influenza vaccine is highly recommended for pregnant clients during any trimester of pregnancy. Pregnancy alters the immune system, making pregnant individuals more susceptible to severe complications from influenza. Vaccination protects both the mother and, through passive antibody transfer, the newborn from influenza infection. Choice C rationale Varicella vaccine is a live attenuated vaccine and is contraindicated during pregnancy due to the theoretical risk of fetal infection. While the actual risk is very low, it is generally deferred until the postpartum period. Women of childbearing age should be screened for immunity and vaccinated if non-immune prior to conception or postpartum. Choice D rationale Measles, mumps, and rubella (MMR) vaccine is a live attenuated vaccine and is contraindicated during pregnancy due to the theoretical risk of fetal infection, particularly with rubella. Rubella infection during pregnancy can lead to congenital rubella syndrome, causing severe birth defects. Vaccination should occur before conception or postpartum. Choice E rationale Human papillomavirus (HPV) vaccine is not routinely recommended during pregnancy. While current data do not suggest harm, the vaccine has not been extensively studied in pregnant individuals. Vaccination should be completed before pregnancy or deferred until the postpartum period.