OBJECTIVE: To estimate the effects of gestational age and other maternal factors on immunologic responses to influenza vaccination. METHODS: Antepartum and postpartum women receiving influenza vaccination as part of routine clinical care were enrolled through four consecutive vaccination seasons (starting October 2006 through January 2010). Immunologic responses to trivalent inactivated influenza vaccine and monovalent H1N1 were assessed as well as factors influencing vaccine responsiveness. Serum samples were obtained at baseline and 4–8 weeks postvaccination. RESULTS: Two hundred thirty-nine participants were included in the current analysis. Seroconversion rates to trivalent inactivated influenza vaccine strains were lowest in the first trimester (54.8%) and immediately postpartum (54.8%) and were highest in the late third trimester (69.6%) and late postpartum (69.4%); these differences were not statistically significant (P=.23). In a multivariable model, higher baseline antibody levels (P<.001) and prior year flu vaccination (P=.03) were both significantly associated with reduced odds of seroconversion. Overall, results were consistent when comparing trivalent inactivated influenza vaccine and monovalent pandemic H1N1 responses. Although there was overall no significant association between gestational age at vaccination (P=.23) or prepregnancy body mass index (P=.16), we observed somewhat lower rates of seroconversion for women vaccinated in the first trimester and for obese women. CONCLUSION: Adequate immunologic responses to inactivated influenza vaccines were demonstrated during pregnancy and the postpartum period. No diminution of immunogenicity was observed in the third trimester, a time of increased clinical vulnerability to influenza. LEVEL OF EVIDENCE: II

During pregnancy the immune system of the mother must protect any activation that may negatively affect the fetus. Changes in susceptibility to infection as well as resolution of some autoimmune disorders represent empirical evidence for pregnancy related alterations in immunity. Sex hormones reach extremely high levels during pregnancy and have been shown to have direct effects on many immune functions including the antiviral response of dendritic cells. Among the immunologically active proteins secreted by monocyte derived DCs (MDDC) are the alpha-defensins 1-3. This family of cationic antimicrobial peptides has a broad spectrum of microbicidal activity and has also been shown to link innate to adaptive immunity by attracting T cells and immature DCs, which are essential for initiating and polarizing the immune response.

Since 2004, the Centers for Disease Control and Prevention and the American College of Obstetricians and Gynecologists have recommended routine influenza vaccination for all pregnant women in any trimester. Maternal influenza vaccination has been shown to decrease the risk of influenza and its complications among pregnant women and their infants in the first 6 months of life. In a recent article published in Vaccine, Donahue and colleagues reported a possible association between influenza vaccination when given very early in the first trimester and spontaneous abortion. There are limited conclusions that should be drawn from this study given the case–control design as well as the small number of patients included in the subanalysis that is the basis for the report. A prior first-trimester safety study from this group, using a similar study design, had not observed any association with spontaneous abortion, and other reports of first-trimester vaccine safety have not observed an association. The lack of a biologically plausible mechanism for the suggested association between previous influenza vaccination and early pregnancy loss is of concern. The study's reported observation is not definitive and needs be replicated in appropriately designed studies before changing clinical practice. Pregnant women are at high risk for severe influenza-related complications, including death, and health care providers have an obligation to their patients to continue to recommend and provide influenza vaccinations.

Chlamydia trachomatis infection is one of the most prevalent bacterial STIs in the USA and worldwide, and women with C. trachomatis infection are at increased risk of acquiring HIV. Because immune activation at the genital mucosa facilitates HIV/SIV infection, C. trachomatis-mediated cytokine induction may contribute to increased HIV transmission in asymptomatic women. To begin to elucidate the mechanisms, we longitudinally analyzed profiles of innate immune factors and HIV infectivity in genital secretions from anatomically specific sites in asymptomatic women during C. trachomatis infection and post-antibiotic treatment. We found higher levels of cytokines and chemokines in endocervical secretions than vaginal secretions. Compared with the convalescent state, G-CSF, IL-1α, and RANTES were elevated in endocervical secretions, IFN-γ and TNF-α were elevated in vaginal secretions, and IFNγ, IL-1β, and MIP1-α were elevated in cervicolavage fluid (CVL), before adjustment of multiple comparisons. Elevated endocervical levels of IP-10 and MCP-1 were associated with the use of hormonal contraception in infected women after successful treatment, suggesting the role of hormonal contraception in inflammation independent of STIs. Importantly, soluble factors found in endocervical secretions during infection enhanced HIV infectivity while no difference in HIV infectivity was found with vaginal secretions or CVL during infection or at convalescence. Taken together, the profiles of immune mediators and in vitro HIV infectivity indicate that the endocervical and vaginal mucosa are immunologically distinct. Our results underscore the importance of considering anatomical site and local sampling methodology when measuring mucosal responses, particularly in the presence of C. trachomatis infection.

Since liver tests are not routinely checked in pregnancy, the prevalence of abnormal liver tests and liver-related abnormalities in pregnancy in a US-based population is not known. We sought to determine the prevalence of abnormal alanine aminotransferase (ALT) among pregnant Individuals who present to labor and delivery for evaluation and to evaluate prevalence of underlying diagnosed liver conditions. Prospective study evaluating liver tests in consecutive samples obtained on the labor and delivery unit. Patient characteristics were compared between those with and without abnormal ALT and those with and without abnormal ALT without a liver-related diagnosis made in clinical practice, using t tests for continuous measures and χ2 or Fisher’s exact tests as appropriate for categorical measures. Logistic regression was utilized to identify factors associated with abnormal ALT in this subcohort to determine predictors of abnormal ALT in those without a known liver-related diagnosis. We collected 1024 laboratory specimens from 996 patients. Of these patients, 131 of 996 (13.2%) had elevated ALT ≥25 IU/L; 20 (2%) had ALT ≥50, 6 (0.6%) had ALT ≥125 and 3 (0.3%) had ALT ≥250. 61/131 (46.6%) of patients with ALT ≥25 IU/L had not had LTs checked during routine pregnancy care. 20 (15%) of individuals with abnormal LT had preeclampsia; 5 (4%) had cholestasis of pregnancy; 1 (0.8%) had hepatitis C; there were no other chronic liver diseases diagnosed. There were no significant demographic or clinical differences between those with and without ALT ≥25, whether liver disease diagnosis was made or not. We identified an over 10% prevalence of abnormal LTs in consecutive pregnant individuals who presented to L&D, most of whom did not have a liver-related condition diagnosed in clinical practice. Among those with liver-related diagnoses, PE and ICP were the most common among individuals with ALT≥25 IU/mL, with chronic liver disease rarely diagnosed. Further evaluation of the role of ALT testing as part of routine prenatal care is needed, particularly in establishing a baseline prevalence of liver test abnormalities in pregnancy and independent association with pregnancy outcomes.