Dataset Information

Detectable Risks in Studies of the Fetal Benefits of Maternal Influenza Vaccination.

ABSTRACT: Maternal influenza vaccination prevents influenza illness in both mothers and newborns. Results from some recent studies have suggested that influenza vaccination might also prevent adverse pregnancy outcomes, such as preterm birth. However, it is challenging to conduct epidemiologic studies to evaluate the benefits to the fetus of maternal influenza vaccination because the causal benefit of vaccination is likely only experienced by the small fraction of the cohort in whom influenza illness is prevented by vaccination. The plausibility of detecting true differences in risks between groups under such conditions is rarely discussed. We aimed to inform the interpretation of studies in which the fetal benefits of maternal influenza vaccination are evaluated by estimating detectable risk ratios and necessary sample sizes for different study scenarios. Estimates of rates of influenza illness, vaccine effectiveness, vaccine uptake, and preterm birth and of the association of influenza illness with preterm birth were identified from the published literature. We calculated detectable risk ratios for preterm birth in vaccinated versus unvaccinated women and the associated sample size requirements. Our results demonstrated that under most scenarios, plausible differences between groups will be extremely challenging to detect (risk ratios for preterm birth of 0.9 to 1.0) and will require sample sizes infeasible for prospective epidemiologic research. This suggests that the large fetal benefits from influenza vaccination observed in epidemiologic studies are unlikely to be causal.

SUBMITTER: Hutcheon JA

PROVIDER: S-EPMC4967598 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature

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Detectable Risks in Studies of the Fetal Benefits of Maternal Influenza Vaccination.

Hutcheon Jennifer A JA Fell Deshayne B DB Jackson Michael L ML Kramer Michael S MS Ortiz Justin R JR Savitz David A DA Platt Robert W RW

American journal of epidemiology 20160630 3

Maternal influenza vaccination prevents influenza illness in both mothers and newborns. Results from some recent studies have suggested that influenza vaccination might also prevent adverse pregnancy outcomes, such as preterm birth. However, it is challenging to conduct epidemiologic studies to evaluate the benefits to the fetus of maternal influenza vaccination because the causal benefit of vaccination is likely only experienced by the small fraction of the cohort in whom influenza illness is p ...[more]

PMID: 27365363

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Project description:Challenges arise when treatment to improve maternal health brings the possibility of risk to fetal health. The coronavirus disease 2019 (COVID-19) vaccine is the most recent, but hardly the only, example. Because pregnant patients are often specifically excluded from trials of new therapies, this is often the dilemma that patients and providers face when considering new treatments. In this study, we used the COVID-19 vaccine as an exemplar to question the broader issue of how society, in general, and obstetricians, in particular, should balance obligations to pregnant women's right of access to new therapeutic agents with the physician's desire to protect the fetus from potential risks. We will argue that in almost all circumstances (with few exceptions, as will also be discussed), maternal benefit and respect for autonomy create the uncertainty that absent safety data bring. Consequently, if pregnant women choose to try new interventions and treatments, such as the COVID-19 vaccination, they should be offered those new regimens and their decision supported. In addition, we will argue that the right solution to avoid the dilemma of absent data is to include pregnant individuals in clinical trials studying new treatments, drugs, and other therapies. We will also discuss the basis for our opinion, which are mainstream obstetrical ethics, precedents in law (supreme court ruling that forbids companies to exclude women from jobs that might pose a risk to the fetus), and historic events (thalidomide). The ethical framework includes the supposition that sacrifice to improve fetal outcome is a virtue and not a mandate. Denying a pregnant patient treatment because of threats to their life can create absurd and paradoxical consequences. Either requiring abortion or premature delivery before proceeding with treatments to optimize maternal health, or risking a patient's own life and ability to parent a child by delaying treatment brings clear and significant risks to fetal and/or neonatal outcomes. With rare exceptions, properly and ethically balancing such consequential actions cannot be undertaken without considering the values and goals of the pregnant patient. Therefore, active participation of both the pregnant patient and their physician in shared decision making is needed.

Project description:BACKGROUND:Placental mRNA was detected in maternal whole blood, raising the possibility of using maternal blood for noninvasive prenatal diagnosis. We investigated fetal mRNA detection in maternal whole blood and determined if it offered advantages over maternal plasma analysis. METHODOLOGY:The concentrations of placental expressed genes, CSH1, KISS1, PLAC4 and PLAC1 in plasma and whole blood from healthy pregnant and non-pregnant individuals were compared by real-time quantitative reverse-transcriptase polymerase chain reaction analysis. Their fetal specificity was investigated by comparing the transcript concentrations in pre- and post-delivery samples and through SNP genotyping by matrix-assisted laser-desorption and ionization time-of-flight mass spectrometry. The gene expression profiles of pregnant and non-pregnant whole blood were investigated by microarray analysis. Upregulated genes in pregnant whole blood were selected for further quantitative analysis. PRINCIPAL FINDINGS:The concentrations of the four transcripts were significantly higher in third trimester maternal whole blood than corresponding plasma without significant correlations. KISS1, PLAC4 and PLAC1 were detected in non-pregnant whole blood but not plasma. The transcripts remained detectable in some postpartum whole blood samples. The PLAC4 mRNA in maternal plasma showed fetal genotype while that in corresponding whole blood indicated both fetal and maternal contributions. Microarray analysis revealed upregulation of genes involved in neutrophil functions in pregnant whole blood including DEFA4, CEACAM8, OLFM4, ORM1, MMP8 and MPO. Though possibly pregnancy-related, they were not pregnancy-specific as suggested by the lack of post-delivery reduction in concentrations. CONCLUSIONS:Maternal plasma is preferred over maternal whole blood for placenta-derived fetal RNA detection. Most studied 'placental' mRNA molecules in maternal whole blood were of maternal origin and might be derived from processes such as 'illegitimate transcription'.

Project description:BackgroundIt has been reported that caseload midwifery, which implies continuity of midwifery care during pregnancy, childbirth, and the postnatal period, improves the outcomes for the mother and child. The aim of this study was to review benefits and risks of caseload midwifery, compared with standard care comparable to the Swedish setting where the same midwife usually provides antenatal care and the checkup postnatally, but does not assist during birth and the first week postpartum.MethodsMedline, Embase, Cinahl, and the Cochrane Library were searched (Nov 4th, 2021) for randomized controlled trials (RCTs). Retrieved articles were assessed and pooled risk ratios calculated when possible, using random-effects meta-analyses. Certainty of evidence was assessed according to GRADE.ResultsIn all, 7,594 patients in eight RCTs were included, whereof five RCTs without major risk of bias, including 5,583 patients, formed the basis for the conclusions. There was moderate certainty of evidence for little or no difference regarding the risk of Apgar ≤ 7 at 5 min, instrumental birth, and preterm birth. There was low certainty of evidence for little or no difference regarding the risk of perinatal mortality, neonatal intensive care, perineal tear, bleeding, and acute caesarean section. Caseload midwifery may reduce the overall risk of caesarean section. Regarding breastfeeding after hospital discharge, maternal mortality, maternal morbidity, health-related quality of life, postpartum depression, health care experience/satisfaction and confidence, available studies did not allow conclusions (very low certainty of evidence). For severe child morbidity and Apgar ≤ 4 at 5 min, there was no literature available.ConclusionsWhen caseload midwifery was compared with models of care that resembles the Swedish one, little or no difference was found for several critical and important child and maternal outcomes with low-moderate certainty of evidence, but the risk of caesarean section may be reduced. For several outcomes, including critical and important ones, studies were lacking, or the certainty of evidence was very low. RCTs in relevant settings are therefore required.

Project description:The relative importance of different attitudes in predicting vaccination among healthcare personnel (HCP) is unclear. We hypothesized that HCP who feel at risk without vaccination or say they would regret not getting vaccinated would be more likely to get vaccinated than HCP who do not expect these emotional benefits.A prospective cohort of 1544 HCP with direct patient care was enrolled from September 18 to December 18, 2010 at Scott & White Healthcare in Texas and Kaiser Permanente Northwest in Oregon and Washington. An Internet-based questionnaire assessed pre-season intention to be vaccinated and included 12 questions on attitudes about vaccination: single-item measures of perceived susceptibility and vaccine effectiveness, 5 items that were summed to form a concerns about vaccine scale, and 5 items summed to form an emotional benefits of vaccination scale. Influenza vaccination status for the 2010-2011 season and for 5 prior seasons was confirmed by medical record extraction.There were significant differences between vaccinated and unvaccinated HCP on all attitude items; 72% of vaccinated HCP agreed that they "worry less about getting the flu" if vaccinated, compared to only 26% of the unvaccinated (odds ratio=7.4, 95% confidence interval=5.8-9.5). In a multivariate model, the emotional benefits scale was the strongest predictor of 2010-2011 seasonal influenza vaccination, after adjusting for other attitude measures, prior vaccination history, and pre-season intention to be vaccinated. The predictive value of the emotional benefits scale was strongest for HCP with low pre-season intention to be vaccinated, where HCP vaccine receipt was 15% versus 83% for those with low versus high scores on the emotional benefits scale.The expected emotional benefits of vaccination strongly affect seasonal influenza vaccination among HCP, even after taking into account other attitudes, pre-season intentions, and prior vaccination history. These attitudes are promising targets for future vaccination campaigns.

Dataset Information

Detectable Risks in Studies of the Fetal Benefits of Maternal Influenza Vaccination.

Publications

Detectable Risks in Studies of the Fetal Benefits of Maternal Influenza Vaccination.

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