Importance Maternal immunization with tetanus toxoid and reduced diphtheria toxoid acellular pertussis (Tdap) vaccine could prevent infant pertussis. The effect of vaccine-induced maternal antibodies on infant responses to diphtheria and tetanus toxoids acellular pertussis (DTaP) immunization is unknown. Objective To evaluate the safety and immunogenicity of Tdap immunization during pregnancy and its effect on infant responses to DTaP. Design, Setting and Participants Phase I, randomized, double-masked, placebo-controlled clinical trial conducted in private (Houston) and academic (Durham, Seattle) obstetric practices from 2008 to 2012. Forty eight healthy 18–45 year-old pregnant women received Tdap (n=33) or placebo (n=15) at 30–32 weeks’ gestation with cross-over Tdap immunization postpartum. Interventions Tdap vaccination at 30–32 weeks’ gestation or post-partum. Outcome Measures Primary: Maternal and infant adverse events, pertussis illness and infant growth and development (Bayley-III screening test) until 13 months of age. Secondary: Antibody concentrations in pregnant women before and 4 weeks after Tdap immunization or placebo, at delivery and 2 months postpartum, and in infants at birth, 2 months, and after the third (7 months) and fourth (13 months) doses of DTaP. Results All participants delivered healthy newborns. No Tdap-associated serious adverse events occurred in women or infants. Injection site reactions after Tdap immunization were reported in 78.8% (95% CI: 61.1%, 91.0%) and 80% (CI: 51.9%, 95.7%) pregnant and postpartum women, respectively. Injection site pain was the predominant symptom. Systemic symptoms were reported in 36.4% (CI: 20.4%, 54.9%) and 73.3% (CI: 44.9%, 92.2%) pregnant and postpartum women, respectively. Malaise and myalgia were most common. Growth and development were similar in both infant groups. No cases of pertussis occurred. Significantly higher concentrations of pertussis antibodies were measured at delivery in women who received Tdap during pregnancy and in their infants at birth and at age 2 months when compared to infants of women immunized postpartum. Antibody responses in infants of Tdap recipients during pregnancy were modestly lower after 3 DTaP doses, but not different following the fourth dose. Conclusions and Relevance This preliminary safety assessment did not find an increased risk of adverse events among women who received Tdap vaccine at 30–32 weeks’ gestation or their infants. Maternal immunization with Tdap resulted in high concentrations of pertussis antibodies in infants during the first 2 months of life and did not substantially alter infant responses to DTaP. Further research is needed to provide definitive evidence of the safety and efficacy of Tdap vaccination during pregnancy. Trial Registration ClinicalTrials.gov, study identifier: NCT00707148. URL: http://www.clinicaltrials.gov

Women in the last trimester of pregnancy were given trivalent inactivated influenza virus vaccine (TIV; A/Sichuan/H3N2, A/Taiwan/H1N1, B/Victoria) or tetanus toxoid (TT). Maternal blood was drawn before immunization and at delivery (median, 5 weeks later); infant blood was obtained within 5 days of birth and 2 months later. Antibody responses to TIV and TT were determined by microneutralization assay and ELISA. T cell response was determined by lymphocyte proliferation. Maternal seroconversion to vaccine antigens was found to one or more influenza antigen in all TIV recipients and to TT in 9 of 13 TT recipients. Significantly higher IgG antibodies to maternal vaccine antigens were present in cord and infant serum. Significant blastogenic responses were seen to influenza A and B in maternal cells of TIV-immunized women but not in cord or infant lymphocytes. Maternal immunization resulted in higher infant levels of vaccine-specific IgG antibody but not in the transfer of specific T lymphocyte response(s) or production of neonatal IgM antibody.

A prospective study of transplacental transmission of human immunodeficiency virus (HIV) showed an increased rate of spontaneous fetal demise in HIV-seropositive mothers: 14 losses in 124 pregnancies. HIV was detected in placental and fetal tissues in 7 of 14 by in situ hybridization. The proportion of fetal infection far exceeded the transmission rate of 13% in liveborn babies. No association was seen between fetal transmission and a maternal history of drug abuse or coinfections; mothers with AIDS more often had fetal loss associated with HIV transmission than did asymptomatic mothers. In affected fetuses, HIV was detected in many tissues and was associated with thymic pathology. This suggests that maternal HIV infection increases the risk for pregnancy loss associated with HIV transmission. The possibility that HIV may be fetotoxic, that thymic dysfunction may interfere with pregnancy progression, or that the intrauterine milieu in HIV-seropositive pregnancies may be unfavorable (or a combination of factors) should be considered.

Twelve pregnant women and one woman who had just given birth were hospitalized with measles in Houston between 1988 and 1990. The most common and serious maternal complication was pneumonitis (seven patients). Other maternal complications included hepatitis (seven patients), premature labor (four patients), spontaneous abortion (one patient), and death (one patient). For four of 13 patients, all of whom had severe measles and pneumonitis due to measles virus, an adverse fetal outcome such as abortion or prematurity was associated with their conditions. Historical accounts describing maternal sequelae of measles have suggested more severe disease in pregnant women, although this observation has not always been confirmed by more recent reports in developed countries. The clinical course in our patients suggests that measles during pregnancy may be associated with serious complications.