2009 pandemic influenza A (H1N1) in pregnancy: a systematic review of the literature

Sex-specific patterns of gene expression following influenza vaccination

Sex-based variations in the immune response to the influenza vaccines was reported, however, the genetic basis responsible for the sex variations in the immune response toward the influenza vaccines remains unclear. Here, the genes responsible for sex-specific responses after vaccination with trivalent inactivated influenza virus were identified. These genes were enriched in virus response pathways, especially interferon signaling. A list of genes showing different responses to the vaccine between females and males were obtained next. Our results demonstrated that females generate stronger immune responses to seasonal influenza vaccines within 24 hours than males. However, most of these genes with variability between sexes had the opposite expression levels after three days, suggesting that males retained the immune responses longer than female. To summary, our study identified genes responsible for the sex variations toward influenza vaccination. Our findings might provide insights into the development of the sex-dependent influenza vaccines.

Exploring the risk of severe outcomes and the role of seasonal influenza vaccination in pregnant women hospitalized with confirmed influenza, Spain, 2010/11-2015/16

Based on previous observations during pandemics and seasonal epidemics, pregnant women are considered at risk of developing severe influenza outcomes after influenza infection. With the aim of preventing severe influenza illness, the World Health Organization (WHO) includes pregnant women as a target group for seasonal influenza vaccination. However, influenza vaccine uptake during pregnancy remains low in many countries, including Spain. The objectives of this study were to increase the evidence of pregnancy as a risk factor for severe influenza illness and to study the potential role of seasonal influenza vaccination in the prevention of severe outcomes in infected pregnant women. Using information from the surveillance of Severe Hospitalized Confirmed Influenza Cases (SHCIC) in Spain, from seasons 2010/11 to 2015/16, we estimated that pregnant women in our study had a relative risk of hospitalization with severe influenza nearly 7.8 times higher than non-pregnant women of reproductive age. Only 5 out of 167 pregnant women with known vaccination status in our study had been vaccinated (3.6%). Such extremely low vaccination coverage only allowed obtaining crude estimates suggesting a protective effect of the vaccine against influenza complications (ICU admission or death). Our overall results support that pregnant women could benefit from seasonal influenza vaccination, in line with national and international recommendations.

The Relationship Between 2009 Pandemic H1N1 Influenza During Pregnancy and Preterm Birth: A Population-based Cohort Study

BACKGROUND

Previous studies of maternal influenza illness and preterm birth have yielded inconsistent results. Our objective was to assess the association between 2009 pandemic H1N1 (pH1N1) influenza during pregnancy and preterm birth in a large obstetrical population.

METHODS

We linked a province-wide birth registry with health administrative databases to identify influenza-coded hospitalizations, emergency department visits, or physician visits among pregnant women during the 2009 H1N1 pandemic (our proxy for clinical pH1N1 influenza illness). Using Cox regression, we estimated adjusted hazard ratios (aHR) for preterm birth and spontaneous preterm birth treating influenza as a time-varying exposure.

RESULTS

Among 192,082 women with a singleton live birth, 2,925 (1.5%) had an influenza-coded health care encounter during the 2009 H1N1 pandemic. Compared with unexposed pregnancy time, there was no association between exposure to the pandemic, with or without clinical influenza illness, and preterm birth (no pH1N1 diagnosis: aHR = 1.0; 95% confidence interval [CI] = 0.98, 1.1; pH1N1 diagnosis: aHR = 1.0; 95% CI = 0.88, 1.2). Among women with preexisting medical conditions, influenza was associated with increased preterm birth (aHR = 1.5; 95% CI = 1.1, 2.2) and spontaneous preterm birth (aHR = 1.7; 95% CI = 1.1, 2.6), and these associations were strongest in the third trimester and when data were analyzed to allow for a transient acute effect of influenza.

CONCLUSIONS

In the general obstetrical population, there was no association between pH1N1 influenza illness and preterm birth, but women with preexisting medical conditions known to increase the risk of influenza-associated morbidity were at elevated risk.

Experience and challenges on influenza and pertussis vaccination in pregnant women

Young infants contribute to relatively high burden of vaccine-preventable diseases, including infections by influenza virus and Bordetella pertussis. Vaccination of pregnant women can enhance transplacental transfer of protective antibody to the fetus and protect the infant against disease during the first few months of life.

Pregnant women are a priority group for seasonal influenza vaccination, due to third-trimester pregnancy being a risk-factor for severe influenza illness. Furthermore, randomized controlled trials confirmed that influenza vaccination during pregnancy confers protection against influenza-confirmed illness in the women, and their infants up to 3 months of age; and is also associated with 20% reduction in all-cause pneumonia among young-infants. Maternal influenza vaccination might also reduce the risk of low-birth weight, preterm births, and stillbirths however, data on this is conflicting.

Vaccination of pregnant women with acellular pertussis vaccines reduces pertussis in their young infants by up to 93%. The increase in specific pertussis antibody among the infants born to vaccinated women might, however, interfere with the active pertussis vaccination of the infant following the primary series of vaccines. The clinical implication of this is yet to be ascertained, particularly since immune responses following the booster vaccine are unaffected.

Vaccination of pregnant women with inactivated influenza vaccine and acellular pertussis vaccine have been demonstrated to confer protection to their young infants, and warrants consideration for inclusion into public health immunization programs, including in low and middle income countries.

Infections During Pregnancy

Several infections have unique consequences or considerations in pregnancy. Some common infections such as urinary tract infections, influenza, sexually transmitted diseases, and vaginitis affect pregnant women differently than the general population, can cause pregnancy complications, and require treatments that are safe in pregnancy. Infections such as hepatitis B and C and human immunodeficiency virus can be transmitted vertically and therefore management focuses on decreasing perinatal transmission. Certain infections can be transmitted in utero and cause congenital infections. Classically, these were grouped together as the TORCH infections, although now several others, including varicella virus, parvovirus, and Zika virus, have also been recognized.

Impact of influenza on outpatient visits and hospitalizations among pregnant women in Catalonia, Spain

OBJECTIVE

To estimate outpatient visits and hospitalization rates due to cardiopulmonary illness attributable to influenza from 2008-09 to 2012-13 in a large cohort of pregnant women from Catalonia, Spain.

METHODS

We estimated the event rates occurring during influenza epidemic, influenza non-epidemic and non-influenza seasons, and by pregnancy status (one year before pregnancy, first, second and third trimester). We fitted quasi-Poisson models in order to identify the variables associated to higher event rates.

RESULTS

During influenza epidemic seasons, pregnant women in their second trimester had the highest rates of outpatient visits (153 per 10,000 women-months). An increased risk of outpatient visits was associated to first or second trimester (adjusted rate ratio (aRR) = 1.17; 95% CI, 1.10-1.23 and aRR, 1.36; 95% CI, 1.28-1.43, respectively) and having any comorbidity (aRR = 1.28; 95% CI, 1.21-1.36). Women during third trimester had the highest rates of hospitalizations (1.60 per 10,000 women-months), and an increased risk of hospitalization was significantly associated to third trimester (aRR, 1.85; 95% CI, 1.01-3.39), having any comorbidity (aRR, 1.93; 95% CI, 1.10-3.41) and the pandemic influenza season (aRR, 2.90 (1.81; 95% CI, 1.81-4.64).

CONCLUSION

Our findings provide significant information regarding influenza burden of disease among pregnant women.

Early prenatal exposure to pandemic influenza A (H1N1) infection and child psychomotor development at 6 months - A population-based cohort study

BACKGROUND

Studies investigating gestational influenza and child neurodevelopment are still scarce, particularly concerning timing of infection in pregnancy. This is the first study to investigate associations between gestational influenza and infant psychomotor development and temperament at 6 months.

METHODS

Data from The Norwegian Influenza Pregnancy Cohort, established during the 2009 swine flu pandemic, were utilized. Information on influenza infection, vaccination, maternal health and child health and development is available from questionnaires, national registry data and maternal blood samples drawn at delivery. Maternal influenza A H1N1 pdm09 infection was serologically confirmed. 609 children with complete data were identified. Children of exposed and non-exposed mothers were compared using generalized linear models.

RESULTS

Children exposed to influenza during gestational weeks (gw) 0-8 had adjusted general development scores indicating slightly delayed development compared to non-exposed children (0.28 standard deviations (SD) 95% confidence interval (CI): -0. 01; 0.58; p = 0.06). The temperamental scores of children exposed during gw 0-8 were slightly higher (0.31 SD; 95% CI: -0. 03; 0.64; p = 0.07) than non-exposed children indicating a more difficult temperament. In comparison, the developmental scores for children exposed in gw 9-40 were -0.31 SD (95% CI: -0. 65; 0.04; p = 0.09) better than non-exposed children, while the temperamental scores were 0.17 (95% CI: -0. 23; 0.56; p = 0.36) for the same period.

CONCLUSION

Modest associations were found between maternal influenza A (H1N1) pdm infection during gestational weeks 0-8 and psychomotor development at 6 months.

Preparing for biological threats: Addressing the needs of pregnant women

Intentional release of infectious agents and biological weapons to cause illness and death has the potential to greatly impact pregnant women and their fetuses. We review what is known about the maternal and fetal effects of seven biological threats: Bacillus anthracis (anthrax); variola virus (smallpox); Clostridium botulinum toxin (botulism); Burkholderia mallei (glanders) and Burkholderia pseudomallei (melioidosis); Yersinia pestis (plague); Francisella tularensis (tularemia); and Rickettsia prowazekii (typhus). Evaluating the potential maternal, fetal, and infant consequences of an intentional release of an infectious agent requires an assessment of several key issues: (1) are pregnant women more susceptible to infection or illness compared to the general population?; (2) are pregnant women at increased risk for severe illness, morbidity, and mortality compared to the general population?; (3) does infection or illness during pregnancy place women, the fetus, or the infant at increased risk for adverse outcomes and how does this affect clinical management?; and (4) are the medical countermeasures recommended for the general population safe and effective during pregnancy? These issues help frame national guidance for the care of pregnant women during an intentional release of a biological threat. Birth Defects Research 109:391-398, 2017.© 2017 Wiley Periodicals, Inc.

Birth outcomes following immunization of pregnant women with pandemic H1N1 influenza vaccine 2009-2010

BACKGROUND

Following the H1N1 influenza pandemic in 2009, pregnant women were recommended to receive both seasonal (TIV) and H1N1 influenza vaccines. This study presents incidence of adverse birth and pregnancy outcomes among a population of pregnant women immunized with TIV and H1N1 vaccines at Kaiser Permanente Northern California during 2009-2010.

METHODS

We telephone surveyed pregnant Kaiser Permanente Northern California members to assess non-medically-attended reactions following H1N1, TIV or both vaccines during 2009-2010 (n=5365) in a separate study. Here we assessed preterm birth (<37weeks), very preterm birth (<32weeks), low birth weight (<2500 g, LBW), very low birth weight (<1500g), small for gestational age, spontaneous abortions, stillbirths and congenital anomalies among this cohort by comparing incidence and 95% confidence intervals between the following immunization groups: TIV only, H1N1 only, H1N1 prior to TIV immunization, TIV prior to H1N1 and both immunizations given at the same time.

RESULTS

Results did not vary significantly between groups. Comparing H1N1 with TIV, incidence were similar for preterm births (6.37vs 6.28/100 births), very preterm births (5.30vs 8.29/1000 births), LBW (4.19vs 2.90/100 births), very LBW (4.54vs 5.52/1000 births), small for gestational age (9.99vs 9.24/1000 births), spontaneous abortion (7.10vs 6.83/1000 pregnancies), stillbirths (7.10vs 4.57/1000 pregnancies), and congenital anomalies (2.66vs 2.43/100 births).

CONCLUSIONS

Although constrained by small sample size, complex vaccine groups, and differential vaccine availability during 2009-2010, this study found no difference in adverse birth outcomes between H1N1 vaccine and TIV.

To vaccinate or not to vaccinate? Women's perception of vaccination in pregnancy: a qualitative study

Background

Vaccination against influenza and pertussis in pregnancy can reduce the significant morbidity and mortality associated with these infections. Despite this, there is poor uptake of both vaccines in pregnancy.

Aim

To explore women’s perception of vaccination in pregnancy and thereby determine the reasons behind such low vaccination rates.

Design & setting

This is a qualitative study undertaken at a large maternity hospital.

Method

Seventeen post-partum women completed a semi-structured interview discussing vaccination. They were recruited from a quantitative study looking at vaccination rates in pregnancy. The interview transcripts were discussed among three researchers and underwent thematic analysis.

Results

Three themes emerged. The first theme explored the influencing factors that shaped the women’s decision to vaccinate in pregnancy. The recommendation of a healthcare provider was the most important influencing factor for this study's cohort of women. The second theme highlighted the deficiency in knowledge women had regarding vaccine safety. The last theme related to the pertussis vaccine, and the reluctance of healthcare providers to discuss and offer this vaccine in pregnancy.

Conclusion

The qualitative approach gives voice to the thoughts and concerns of women as they make the complex decision to vaccinate in pregnancy. Clinicians must be cognizant of the important role they play in advising women to vaccinate in pregnancy. They must advise women that the vaccine is safe and address any of their concerns. Lastly, a message on vaccine safety should be included in future public health campaigns to promote vaccination in pregnancy.

Severe influenza A(H1N1)pdm09 in pregnant women and neonatal outcomes, State of Sao Paulo, Brazil, 2009

To investigate the factors associated with death and describe the gestational outcomes in pregnant women with influenza A(H1N1)pdm09, we conducted a case-control study (deaths and recovered) in hospitalized pregnant women with laboratory-confirmed influenza A(H1N1)pdm09 with severe acute respiratory illness (SARI) in the state of São Paulo from June 9 to December 1, 2009. All cases were evaluated, and four controls that were matched by the epidemiological week of hospitalization of the case were randomly selected for each case. Cases and controls were selected from the National Disease Notification System-SINAN Influenza-web. The hospital records from 126 hospitals were evaluated, and home interviews were conducted using standardized forms. A total of 48 cases and 185 controls were investigated. Having had a previous health visit to a healthcare provider for an influenza episode before hospital admission was a risk factor for death (adjusted OR (ORadj) of 7.93, 95% CI 2.19-28.69). Although not significant in the multiple analysis (ORadj of 2.13, 95% CI 0.91-5.00), the 3rd trimester deserves attention, with an OR = 2.22, 95% CI 1.13-4.37 in the univariate analysis. Antiviral treatment was a protective factor when administered within 48 hours of symptom onset (ORadj = 0.16, 95% CI 0.05-0.50) and from 48 to 72 hours (ORadj = 0.09, 95% CI 0.01-0.87). There was a higher proportion of fetal deaths and preterm births among cases (p = 0.001) and live births with low weight (p = 0.019), compared to control subjects who gave birth during hospitalization. After discharge, control subjects had a favorable neonatal outcome. Early antiviral treatment during the presence of a flu-like illness is an important factor in reducing mortality from influenza in pregnant women and unfavorable neonatal outcomes. It is important to monitor pregnant women, particularly in the 3rd trimester of gestation, with influenza illness for diagnosis and early treatment.

Association of spontaneous abortion with receipt of inactivated influenza vaccine containing H1N1pdm09 in 2010-11 and 2011-12

INTRODUCTION

Inactivated influenza vaccine is recommended in any stage of pregnancy, but evidence of safety in early pregnancy is limited, including for vaccines containing A/H1N1pdm2009 (pH1N1) antigen. We sought to determine if receipt of vaccine containing pH1N1 was associated with spontaneous abortion (SAB).

METHODS

We conducted a case-control study over two influenza seasons (2010-11, 2011-12) in the Vaccine Safety Datalink. Cases had SAB and controls had live births or stillbirths and were matched on site, date of last menstrual period, and age. Of 919 potential cases identified using diagnosis codes, 485 were eligible and confirmed by medical record review. Exposure was defined as vaccination with inactivated influenza vaccine before the SAB date; the primary exposure window was the 1-28days before the SAB.

RESULTS

The overall adjusted odds ratio (aOR) was 2.0 (95% CI, 1.1-3.6) for vaccine receipt in the 28-day exposure window; there was no association in other exposure windows. In season-specific analyses, the aOR in the 1-28days was 3.7 (95% CI 1.4-9.4) in 2010-11 and 1.4 (95% CI 0.6-3.3) in 2011-12. The association was modified by influenza vaccination in the prior season (post hoc analysis). Among women who received pH1N1-containing vaccine in the previous influenza season, the aOR in the 1-28days was 7.7 (95% CI 2.2-27.3); the aOR was 1.3 (95% CI 0.7-2.7) among women not vaccinated in the previous season. This effect modification was observed in each season.

CONCLUSION

SAB was associated with influenza vaccination in the preceding 28days. The association was significant only among women vaccinated in the previous influenza season with pH1N1-containing vaccine. This study does not and cannot establish a causal relationship between repeated influenza vaccination and SAB, but further research is warranted.

Infections in Pregnancy

Infections during pregnancy may affect a developing fetus. If left untreated, these infections can lead to the death of the mother, fetus, or neonate and other adverse sequelae. There are many factors that impact infection during pregnancy, such as the immune system changes during pregnancy, hormonal flux, stress, and the microbiome. We review some of the outcomes of infection during pregnancy, such as preterm birth, chorioamnionitis, meningitis, hydrocephaly, developmental delays, microcephaly, and sepsis. Transmission routes are discussed regarding how a pregnant woman may pass her infection to her fetus. This is followed by examples of infection during pregnancy: bacterial, viral, parasitic, and fungal infections. There are many known organisms that are capable of producing similar congenital defects during pregnancy; however, whether these infections share common mechanisms of action is yet to be determined. To protect the health of pregnant women and their offspring, additional research is needed to understand how these intrauterine infections adversely affect pregnancies and/or neonates in order to develop prevention strategies and treatments.

Impact of pregnancy on observed sex disparities among adults hospitalized with laboratory-confirmed influenza, FluSurv-NET, 2010-2012

INTRODUCTION

Previous FluSurv-NET studies found that adult females had a higher incidence of influenza-associated hospitalizations than males. To identify groups of women at higher risk than men, we analyzed data from 14 FluSurv-NET sites that conducted population-based surveillance for laboratory-confirmed influenza-associated hospitalizations among residents of 78 US counties.

METHODS

We analyzed 6292 laboratory-confirmed, geocodable (96%) adult cases collected by FluSurv-NET during the 2010-12 influenza seasons. We used 2010 US Census and 2008-2012 American Community Survey data to calculate overall age-adjusted and age group-specific female:male incidence rate ratios (IRR) by race/ethnicity and census tract-level poverty. We used national 2010 pregnancy rates to estimate denominators for pregnant women aged 18-49. We calculated male:female IRRs excluding them and IRRs for pregnant:non-pregnant women.

RESULTS

Overall, 55% of laboratory-confirmed influenza cases were female. Female:male IRRs were highest for females aged 18-49 of high neighborhood poverty (IRR 1.50, 95% CI 1.30-1.74) and of Hispanic ethnicity (IRR 1.70, 95% CI 1.34-2.17). These differences disappeared after excluding pregnant women. Overall, 26% of 1083 hospitalized females aged 18-49 were pregnant. Pregnant adult females were more likely to have influenza-associated hospitalizations than their non-pregnant counterparts (relative risk [RR] 5.86, 95% CI 5.12-6.71), but vaccination levels were similar (25.5% vs 27.8%).

CONCLUSIONS

Overall rates of influenza-associated hospitalization were not significantly different for men and women after excluding pregnant women. Among women aged 18-49, pregnancy increased the risk of influenza-associated hospitalization sixfold but did not increase the likelihood of vaccination. Improving vaccination rates in pregnant women should be an influenza vaccination priority.

Influenza epidemiology and immunization during pregnancy: Final report of a World Health Organization working group

From 2014 to 2017, the World Health Organization convened a working group to evaluate influenza disease burden and vaccine efficacy to inform estimates of maternal influenza immunization program impact. The group evaluated existing systematic reviews and relevant primary studies, and conducted four new systematic reviews. There was strong evidence that maternal influenza immunization prevented influenza illness in pregnant women and their infants, although data on severe illness prevention were lacking. The limited number of studies reporting influenza incidence in pregnant women and infants under six months had highly variable estimates and underrepresented low- and middle-income countries. The evidence that maternal influenza immunization reduces the risk of adverse birth outcomes was conflicting, and many observational studies were subject to substantial bias. The lack of scientific clarity regarding disease burden or magnitude of vaccine efficacy against severe illness poses challenges for robust estimation of the potential impact of maternal influenza immunization programs.

Immunization During Pregnancy: Impact on the Infant

Maternal immunization has undergone a paradigm shift in recent years, as women and healthcare providers accept and recognize the benefits of this strategy not only for the pregnant woman but also for the developing fetus and young infant. This article reviews the evidence for active immunization during pregnancy, with an emphasis on perinatal and infant outcomes. Current recommendations for immunization during pregnancy are presented, with particular focus on the routinely recommended vaccines during pregnancy: influenza and Tdap (tetanus, diphtheria, and pertussis). We discuss future research directions, maternal vaccines in development, and considerations for optimizing and advancing this underutilized strategy.

Implementation of the Recommendation to Vaccinate Pregnant Women against Seasonal Influenza - Vaccination Rates and Acceptance

Introduction In Germany vaccination recommendations are revised annually and published by the Standing Committee on Vaccination at the Robert Koch Institute (STIKO). In 2010 the vaccination recommendations were amended to include the proposal that pregnant women in the 2nd trimester of pregnancy and pregnant women with additional underlying disease in the 1st trimester of pregnancy should be vaccinated against seasonal influenza. This paper reports on vaccination rates and the factors influencing them. Method A cross-sectional study was carried out in two level 1 perinatal centers in two different German federal states (Saarland and Rhineland-Palatinate) during the influenza seasons of 2012/2013 and 2013/2014. A total of 253 pregnant women were included in the study. Pregnant women were interviewed using a standardized, pre-tested questionnaire and asked whether they were aware of the recommendation to vaccinate against seasonal influenza and about possible factors which might influence their decision to be vaccinated. In addition, data from their vaccination certificates and pregnancy passports were evaluated. Results Overall, the records of only 19.5 % of the pregnant women showed that they had been vaccinated against influenza in pregnancy. Among the group of pregnant women who had a previous history of vaccinations against influenza the willingness to be vaccinated was high (43.3 %) and this figure was statistically significant. The vaccination rate was even higher (49.9 %) and even more statistically significant among pregnant women whose gynecologist or family physician had recommended that they should be vaccinated. In contrast, only 3.3 % of pregnant women who had not been given the recommendation to vaccinate by their physicians were vaccinated against influenza. Discussion The failure to recommend that pregnant women be vaccinated against influenza and women's lack of any previous experience of influenza vaccination were the main reasons for the inadequate influenza vaccination coverage in pregnancy. Conclusion One of the key points to increase the influenza vaccination rate is to intensify the counselling of the pregnant women through the gynecologist.

Report of the WHO technical consultation on the effect of maternal influenza and influenza vaccination on the developing fetus: Montreal, Canada, September 30-October 1, 2015

In 2012, the World Health Organization (WHO) released a position paper on influenza vaccination recommending that pregnant women have the highest priority for seasonal vaccination in countries where the initiation or expansion of influenza immunization programs is under consideration. Although the primary goal of the WHO recommendation is to prevent influenza illness in pregnant women, the potential benefits of maternal immunization in protecting young infants are also recognized. The extent to which maternal influenza vaccination may prevent adverse birth outcomes such as preterm birth or small-for-gestational-age birth, however, is unclear as available studies are in disagreement. To inform WHO about the empirical evidence relating to possible benefits of influenza vaccination on birth outcomes, a consultation of experts was held in Montreal, Canada, September 30-October 1, 2015. Presentations and discussions covered a broad range of issues, including influenza virus infection during pregnancy and its effect on the health of the mother and the fetus, possible biological mechanisms for adverse birth outcomes following maternal influenza illness, evidence on birth outcomes following influenza illness during pregnancy, evidence from both observational studies and randomized controlled trials on birth outcomes following influenza vaccination of pregnant women, and methodological issues. This report provides an overview of the presentations, discussions and conclusions.

Neuraminidase inhibitors during pregnancy and risk of adverse neonatal outcomes and congenital malformations: population based European register study

Objective To evaluate the possible effects of exposure to neuraminidase inhibitors during embryo-fetal life with respect to adverse neonatal outcomes and congenital malformations.Design Population based multinational observational cohort study and meta-analysis.Setting National registers covering information on maternal healthcare, births, and prescriptions in Denmark, Norway, and Sweden and the EFEMERIS database from the Haute-Garonne district in France.Participants All women together with their singleton infants born between 1 January 2008 and 31 December 2010. Only infants born at 154 days of gestation or later were included. Infants were defined as exposed if the women filled a prescription during pregnancy for either of the two neuraminidase inhibitors oseltamivir or zanamivir.Main outcomes Low birth weight, low Apgar score, preterm birth, small for gestational age birth, stillbirth, neonatal mortality, neonatal morbidity, and congenital malformations. Crude and adjusted hazard ratios of preterm birth were estimated using Cox regression models. Crude and adjusted odds ratios for other outcomes were estimated by logistic regression models.Results The study included 5824 (0.8%) exposed women and their infants and 692 232 who were not exposed. Exposure to neuraminidase inhibitors in utero was not associated with increased risks of any of the investigated neonatal outcomes, including low birth weight (adjusted odds ratio 0.77, 95% confidence interval 0.65 to 0.91), low Apgar score (adjusted odds ratio 0.87, 0.67 to 1.14), preterm birth (adjusted hazard ratio 0.97, 0.86 to 1.10), small for gestational age birth (adjusted odds ratio 0.72, 0.59 to 0.87), stillbirth (adjusted odds ratio 0.81, 0.51 to 1.30), neonatal mortality (adjusted odds ratio 1.13, 0.56 to 2.28), and neonatal morbidity (adjusted odds ratio 0.92, 0.86 to 1.00). No increased risk of congenital malformations overall associated with maternal exposure was observed during the first trimester (adjusted odds ratio 1.06, 0.77 to 1.48). Similarly, no significantly increased risks of any of the outcomes were observed in an analysis restricted to oseltamivir alone.Conclusions This large multinational register study found no increased risks of adverse neonatal outcomes or congenital malformations associated with exposure to neuraminidase inhibitors during embryo-fetal life. The results support previously reported findings that the use of neuraminidase inhibitors is not associated with increased risks of adverse fetal or neonatal outcomes.

Strategies To Boost Maternal Immunization To Achieve Further Gains In Improved Maternal And Newborn Health

Despite the indisputable successes of the United Nations Millennium Development Goals, which include goals on improving maternal health and reducing child mortality, millions of mothers and newborns still die tragically and unnecessarily each year. Many of these deaths result from vaccine-preventable diseases, since obstacles such as cost and accessibility have hampered efforts to deliver efficacious vaccines to those most in need. Additionally, many vaccines given to mothers and children under age five are not suitable for newborns, since their maturing immune systems do not respond optimally during the first few months of life. Maternal immunization-the process by which a pregnant woman's immune system is fortified against a particular disease and the protection is then transferred to her unborn child-has emerged as a strategy to prevent many unnecessary maternal and newborn deaths. We review vaccines that are already used for maternal immunization, analyze vaccines under development that could be used for maternal immunization strategies in the future, and recommend that policy makers use maternal immunization for improved maternal and newborn health.

Cost-effectiveness of maternal influenza immunization in Bamako, Mali: A decision analysis

Background

Maternal influenza immunization has gained traction as a strategy to diminish maternal and neonatal mortality. However, efforts to vaccinate pregnant women against influenza in developing countries will require substantial investment. We present cost-effectiveness estimates of maternal influenza immunization based on clinical trial data from Bamako, Mali.

Methods

We parameterized a decision-tree model using prospectively collected trial data on influenza incidence, vaccine efficacy, and direct and indirect influenza-related healthcare expenditures. Since clinical trial participants likely had better access to care than the general Malian population, we also simulated scenarios with poor access to care, including decreased healthcare resource utilization and worse influenza-related outcomes.

Results

Under base-case assumptions, a maternal influenza immunization program in Mali would cost $857 (95% UI: $188-$2358) per disability-adjusted life year (DALY) saved. Adjusting for poor access to care yielded a cost-effectiveness ratio of $486 (95% UI: $105-$1425) per DALY saved. Cost-effectiveness ratios were most sensitive to changes in the cost of a maternal vaccination program and to the proportion of laboratory-confirmed influenza among infants warranting hospitalization. Mean cost-effectiveness estimates fell below Mali’s GDP per capita when the cost per pregnant woman vaccinated was $1.00 or less with no adjustment for access to care or $1.67 for those with poor access to care. Healthcare expenditures for lab-confirmed influenza were not significantly different than the cost of influenza-like illness.

Conclusions

Maternal influenza immunization in Mali would be cost-effective in most settings if vaccine can be obtained, managed, and administered for ≤$1.00 per pregnant woman.

Regulation of Matrix Metalloproteinases-2 and -9 Gene Expression in Cultured Human Fetal Membrane Cells by Influenza Virus Infection

In order to understand a possible etiology of adverse pregnancy outcomes associated with intrauterine influenza virus infection, we examined the effect of influenza virus infection on gene expression of matrix metalloproteinases (MMPs) in cultured amnion epithelial, amnion mesenchymal and chorion trophoblast cells prepared from human fetal membrane tissues by gelatin zymography, Western blotting and reverse transcriptase-PCR. The cells were infected with influenza A (H1N1) virus. The levels of pro-MMP-9 activity in culture supernatants of three types of cells were increased during the period of 24-48 h after the virus infection as compared to those of mock infection. Chorion trophoblast cells spontaneously released a much greater level of pro-MMP-2 activity than amnion epithelial and amnion mesenchymal cells. The cleavage of pro-MMP-2 into an active intermediate form was enhanced in chorion trophoblast cells by the virus infection. The activity levels of MMP-2 and MMP-9 in culture supernatants were consistent with their protein levels. The virus infection induced the mRNA expression of MMP-9, but not MMP-2, in three types of cells. These results suggest that influenza virus infection induces the gene expression of MMP-9 and the cleavage of pro-MMP-2 into an active intermediate form in human fetal membrane cells, resulting in weakening of the membranes through extracellular matrix degradation. Therefore, it is possible that the regulation of MMPs gene expression in fetal membrane cells by influenza virus infection is implicated in a part of the etiology of adverse pregnancy outcomes associated with intrauterine infection with the virus.

Text messages for influenza vaccination among pregnant women: A randomized controlled trial

OBJECTIVE

To evaluate if text message reminders increase the likelihood of receiving the influenza vaccine among pregnant women.

METHODS

Pregnant women were randomized to either receive or not receive weekly text messages. Women were told the messages would be about health-related behavior in pregnancy. Those randomized to the intervention group received two messages weekly for four consecutive weeks reinforcing that the influenza vaccine is recommended for all pregnant women and safe during pregnancy and breastfeeding. Women were contacted six weeks postpartum to determine if they had received the vaccine. Sample size calculation determined that 108 women were required in both groups to see a 75% increase in vaccination rates over baseline in the text message group compared to the control group.

RESULTS

Recruitment began November 4, 2013, and 317 women were randomized. The mean gestational age at recruitment was 22weeks. There were 40/129 (31%) women in the text message group and 41/152 (27%) women in the control group who received the vaccine (p=0.51). Significant predictors of vaccine acceptance were being married compared to single (95% vs. 67%, p<0.001), having higher household income (55% vs. 39%, p=0.03) and having received the vaccine before (77% vs. 36%, p<0.001). Among women receiving text messages, the majority were satisfied, with only 15/129 (12%) reporting that they did not like receiving the messages, and 24/129 (19%) stating that the information in the messages was not helpful.

CONCLUSION

Weekly text messages reinforcing the recommendation for and safety of the influenza vaccine in pregnancy did not increase the likelihood of actually receiving the vaccine among pregnant women. Overall vaccination rates were low, highlighting the need for patient education and innovative techniques to improve vaccine acceptance. Registered with ClinicalTrials.gov at http://www.clinicaltrials.gov, registration number NCT 02428738.

Maternal influenza and birth outcomes: systematic review of comparative studies

BACKGROUND

Although pregnant women are considered at high risk for severe influenza disease, comparative studies of maternal influenza and birth outcomes have not been comprehensively summarised.

OBJECTIVE

To review comparative studies evaluating maternal influenza disease and birth outcomes.

SEARCH STRATEGY

We searched bibliographic databases from inception to December 2014.

SELECTION CRITERIA

Studies of preterm birth, small-for-gestational-age (SGA) birth or fetal death, comparing women with and without clinical influenza illness or laboratory-confirmed influenza infection during pregnancy.

DATA COLLECTION AND ANALYSIS

Two reviewers independently abstracted data and assessed study quality.

MAIN RESULTS

Heterogeneity across 16 studies reporting preterm birth precluded meta-analysis. In a subgroup of the highest-quality studies, two reported significantly increased preterm birth (risk ratios (RR) from 2.4 to 4.0) following severe 2009 pandemic H1N1 (pH1N1) influenza illness, whereas those assessing mild-to-moderate pH1N1 or seasonal influenza found no association. Five studies of SGA birth showed no discernible patterns with respect to influenza disease severity (pooled odds ratio 1.24; 95% CI 0.96-1.59). Two fetal death studies were of sufficient quality and size to permit meaningful interpretation. Both reported an increased risk of fetal death following maternal pH1N1 disease (RR 1.9 for mild-to-moderate disease and 4.2 for severe disease).

CONCLUSIONS

Comparative studies of preterm birth, SGA birth and fetal death following maternal influenza disease are limited in number and quality. An association between severe pH1N1 disease and preterm birth and fetal death was reported by several studies; however, these limited data do not permit firm conclusions on the magnitude of any association.

TWEETABLE ABSTRACT

Comparative studies are limited in quality but suggest severe pandemic H1N1 influenza increases preterm birth.

Knowledge and attitude of pregnant women toward flu vaccination: a cross-sectional survey

OBJECTIVE

The study was conducted to explore the knowledge of pregnant women about influenza, influenza vaccine during pregnancy and the attitudes regarding immunization.

METHODS

A questionnaire based on the model proposed by Yudin in 2009 was translated, adapted and administered to 309 pregnant women in the third trimester of pregnancy between October 1 and December 1, 2013 at San Giovanni Calibita Fatebenefratelli hospital of Rome (Italy).

RESULTS

Most of the interviewed women (68.9%) answered that influenza is highly contagious, 34.6% of them believed that pregnant women have the same risk of complications as non-pregnant women. Only 5.8% were aware that the vaccine is recommended for women in the second and third trimester of pregnancy and only 14.2% of women answered that the vaccine is safe during pregnancy. Only 3/309 women reported recommendation and offer of vaccination during current pregnancy, but none of them was vaccinated.

CONCLUSIONS

Overall, knowledge regarding influenza, implications during pregnancy and influenza vaccine was poor among pregnant women. In Italy, the National Vaccine Prevention Plan 2012-2014 recommends influenza vaccine during pregnancy, but only 18/309 were aware of this recommendation. These results suggest that in order to increase influenza vaccine acceptance it is necessary to improve pregnant women knowledge about influenza and to offer education to healthcare providers.

Amino acid polymorphism at residue 222 of the receptor-binding site of the hemagglutinin of the pandemic influenza A(H1N1)pdm09 from patients 166 with lethal virus pneumonia in 2012-2014

Survey data from autopsy specimens from patients who died from pneumonia caused by the influenza A(H1N1) pdm09 in 2012-2014 and mutant forms of influenza virus in these patients (position 222 in the receptor-binding region of hemagglutinin) were presented. In total, according to aggregate data, obtained with three different methods (sequencing, next-generation sequencing (NGS), virus isolation) mutant viruses were detected in 17 (41%) from 41 patients. The proportion of the mutant forms in viral populations ranged from 1% to 69.2%. The most frequent mixture was the wild type (D222) and mutant (D222G), with proportion of mutant type ranged from 3.3% to 69.2% in the viral population. Mutation D222N (from 1.1% to 5.5%) was found rarely. Composition of the viral population from one patient is extremely heterogeneous: in left lung there was only wild type D222, meantime in right lung - mixture of mutant forms 222D/N/G (65.4/32.5/1.1%), in trachea - mixture 222D/G/Y/A (61.8/35.6/1.2/1.4%, respectively), and in bronchi compound of 222D/G/N/A (64.3/33.7/1/1%, respectively) were detected. The obtained data indicate that the process of adaptation of the virus in the lower respiratory tract is coupled with the appearance of different virus variants with mutations in the receptor-binding region. Mutant forms of the virus are observed in the lower respiratory tract of the majority of patients with lethal viral pneumonia. However, if they are a minor part of the population, they cannot be detected by the method of conventional sequencing. They can be identified using the NGS methods.

Influenza immunization during pregnancy: Benefits for mother and infant

The serious consequences of influenza infection during pregnancy have been recognized for almost a century. In this article, we reviewed the evidence on the immunogenicity, safety and impact of maternal influenza immunization for both mother and child. After vaccination, pregnant women have similar protective titers of anti-influenza antibodies as non-pregnant women, demonstrating that pregnancy does not alter the trivalent inactivated influenza vaccine immune response. Studies from the United States, Europe and resource-constrained regions demonstrate that maternal vaccination is associated with increased anti-influenza antibody concentrations and protection in the newborn child as well as the immunized mother. Given the acceptable safety profile of influenza vaccines and the World Health Organization's recommendation for its use in pregnant women, maternal vaccination with inactivated influenza vaccine is a cost-effective approach to decrease influenza disease in newborns. However, as seen for influenza immunization in the elderly, the protective efficacy of current inactivated vaccines in protection of newborns is 50% at best, indicating significant room for vaccine improvement, which could potentially be achieved by addition of a safe and effective adjuvant. Thus, global deployment of inactivated influenza immunization during pregnancy would have substantial and measurable health benefits for mothers and their newborns.

Circulating Influenza Virus and Adverse Pregnancy Outcomes: A Time-Series Study

Individual-level epidemiologic studies of pregnancy outcomes after maternal influenza are limited in number and quality and have produced inconsistent results. We used a time-series design to investigate whether fluctuation in influenza virus circulation was associated with short-term variation in population-level rates of preterm birth, stillbirth, and perinatal death in Ontario between 2003 and 2012. Using Poisson regression, we assessed the association between weekly levels of circulating influenza virus and counts of outcomes offset by the number of at-risk gestations during 3 gestational exposure windows. The rate of preterm birth was not associated with circulating influenza level in the week preceding birth (adjusted rate ratio = 1.01, 95% confidence interval: 1.00, 1.02) or in any other exposure window. These findings were robust to alternate specifications of the model and adjustment for potential confounding. Stillbirth and perinatal death rates were similarly not associated with gestational exposure to influenza circulation during late pregnancy. We could not assess mortality outcomes relative to early gestational exposure because of missing dates of conception for many stillbirths. In this time-series study, population-level influenza circulation was not associated with short-term variation in rates of preterm birth, stillbirth, or perinatal death.

Human Influenza Virus Infections

Seasonal and pandemic influenza are the two faces of respiratory infections caused by influenza viruses in humans. As seasonal influenza occurs on an annual basis, the circulating virus strains are closely monitored and a yearly updated vaccination is provided, especially to identified risk populations. Nonetheless, influenza virus infection may result in pneumonia and acute respiratory failure, frequently complicated by bacterial coinfection. Pandemics are, in contrary, unexpected rare events related to the emergence of a reassorted human-pathogenic influenza A virus (IAV) strains that often causes increased morbidity and spreads extremely rapidly in the immunologically naive human population, with huge clinical and economic impact. Accordingly, particular efforts are made to advance our knowledge on the disease biology and pathology and recent studies have brought new insights into IAV adaptation mechanisms to the human host, as well as into the key players in disease pathogenesis on the host side. Current antiviral strategies are only efficient at the early stages of the disease and are challenged by the genomic instability of the virus, highlighting the need for novel antiviral therapies targeting the pulmonary host response to improve viral clearance, reduce the risk of bacterial coinfection, and prevent or attenuate acute lung injury. This review article summarizes our current knowledge on the molecular basis of influenza infection and disease progression, the key players in pathogenesis driving severe disease and progression to lung failure, as well as available and envisioned prevention and treatment strategies against influenza virus infection.

Influenza pathogenicity during pregnancy in women and animal models

Pregnant women are at the highest risk to develop severe and even fatal influenza. The high vulnerability of women against influenza A virus infections during pregnancy was repeatedly highlighted during influenza pandemics including the pandemic of this century. In 2009, mortality rates were particularly high among otherwise healthy pregnant women. However, our current understanding of the molecular mechanisms involved in severe disease development during pregnancy is still very limited. In this review, we summarize the knowledge on the clinical observations in influenza A virus-infected pregnant women. In addition, knowledge obtained from few existing experimental infections in pregnant animal models is discussed. Since clinical data do not provide in-depth information on the pathogenesis of severe influenza during pregnancy, adequate animal models are urgently required that mimic clinical findings. Studies in pregnant animal models will allow the dissection of involved molecular disease pathways that are key to improve patient management and care.

Severe pneumonia caused by adenovirus 7 in pregnant woman: Case report and review of the literature

We report a rare case of adenoviral pneumonia in a previously healthy pregnant woman at 26⁺⁴ weeks' gestation. She presented with persistent high fever, cough for 5 days, and developed progressive dyspnea with hypoxemic respiratory failure and bilateral pulmonary infiltrates with pleural effusions. Aggressive supportive care and timely obstetrical management saved the mother and prevented preterm delivery and fetal anomaly.

Sepsis during pregnancy or the postpartum period

Sepsis is an important cause of maternal morbidity and mortality worldwide. Early recognition and timely treatment are the key to ensuring a favourable outcome. This article reviews recent literature about definitions, pathophysiology, incidence, diagnosis, management, treatment, prevention and outcome of sepsis during pregnancy and the postpartum period.

Reclassifying causes of obstetric death in Mexico: a repeated cross-sectional study

Objective

To describe causes of maternal mortality in Mexico over eight years, with particular attention to indirect obstetric deaths and socioeconomic disparities.

Methods

We conducted a repeated cross-sectional study using the 2006–2013 Búsqueda intencionada y reclasificación de muertes maternas (BIRMM) data set. We used frequencies to describe new cases, cause distributions and the reclassification of maternal mortality cases by the BIRMM process. We used statistical tests to analyse differences in sociodemographic characteristics between direct and indirect deaths and differences in the proportion of overall direct and indirect deaths, by year and by municipality poverty level.

Findings

A total of 9043 maternal deaths were subjected to the review process. There was a 13% increase (from 7829 to 9043) in overall identified maternal deaths and a threefold increase in the proportion of maternal deaths classified as late maternal deaths (from 2.1% to 6.9%). Over the study period direct obstetric deaths declined, while there was no change in deaths from indirect obstetric causes. Direct deaths were concentrated in women who lived in the poorest municipalities. When compared to those dying of direct causes, women dying of indirect causes had fewer pregnancies and were slightly younger, better educated and more likely to live in wealthier municipalities.

Conclusion

The BIRMM is one approach to correct maternal death statistics in settings with poor resources. The approach could help the health system to rethink its strategy to reduce maternal deaths from indirect obstetric causes, including prevention of unwanted pregnancies and improvement of antenatal and post-obstetric care.

Maternal vaccination for the prevention of influenza: current status and hopes for the future

Influenza is an important cause of morbidity and mortality among pregnant women and young infants, and influenza infection during pregnancy has also been associated with adverse obstetric and birth outcomes. There is substantial evidence - from randomized trials and observational studies - that maternal influenza immunization can protect pregnant women and their infants from influenza disease. In addition, there is compelling observational evidence that prevention of influenza in pregnant women can also protect against certain adverse pregnancy outcomes, including stillbirth and preterm birth. In this article we will review and evaluate the literature on both the burden of influenza disease in pregnant women and infants, as well as the multiple potential benefits of maternal influenza immunization for mother, fetus, and infant. We will also review key clinical aspects of maternal influenza immunization, as well as identify remaining knowledge gaps, and discuss avenues for future investigation.

Impact of Middle East Respiratory Syndrome coronavirus (MERS-CoV) on pregnancy and perinatal outcome

Background

Middle East Respiratory Syndrome coronavirus (MERS-CoV) is a viral respiratory disease. Most people infected with MERS-CoV develop severe acute respiratory illness. It was first reported in Saudi Arabia in 2012 and has since spread to several other countries. We report the clinical course of MERS-CoV infection in a pregnant woman who acquired the infection during the last trimester.

Case presentation

The patient is a 33-year-old female working as a critical care nurse. She was 32 weeks pregnant when she presented with respiratory symptoms after direct contact with a MERS-COV patient. Although the patient was in respiratory failure, necessitated mechanical ventilation, and intensive care (ICU) admission, a healthy infant was delivered. The mother recovered. To the best of our knowledge, this is the first reported case of a laboratory-confirmed Middle East Respiratory Syndrome Coronavirus in a pregnant woman.

Conclusions

Middle East Respiratory Syndrome coronavirus (MERS-CoV) known to cause severe acute respiratory illness associated with a high risk of mortality Various factors may have contributed to the successful outcome of this patient such as young age, presentation during the last stages of pregnancy, and possible differences in immune response.

Southern Hemisphere Influenza and Vaccine Effectiveness Research and Surveillance

The 2009 influenza A(H1N1)pdm09 pandemic highlighted the need for improved scientific knowledge to support better pandemic preparedness and seasonal influenza control. The Southern Hemisphere Influenza and Vaccine Effectiveness Research and Surveillance (SHIVERS) project, a 5-year (2012–2016) multiagency and multidisciplinary collaboration, aimed to measure disease burden, epidemiology, aetiology, risk factors, immunology, effectiveness of vaccination and other prevention strategies for influenza and other respiratory infectious diseases of public health importance. Two active, prospective, population-based surveillance systems were established for monitoring influenza and other respiratory pathogens among those hospitalized patients with acute respiratory illness and those enrolled patients seeking consultations at sentinel general practices. In 2015, a sero-epidemiological study will use a sample of patients from the same practices. These data will provide a full picture of the disease burden and risk factors from asymptomatic infections to severe hospitalized disease and deaths and related economic burden. The results during the first 2 years (2012–2013) provided scientific evidence to (a) support a change to NZ's vaccination policy for young children due to high influenza hospitalizations in these children; (b) contribute to the revision of the World Health Organization's case definition for severe acute respiratory illness for global influenza surveillance; and (c) contribute in part to vaccine strain selection using vaccine effectiveness assessment in the prevention of influenza-related consultations and hospitalizations. In summary, SHIVERS provides valuable international platforms for supporting seasonal influenza control and pandemic preparedness, and responding to other emerging/endemic respiratory-related infections.

Critical Illness in Pregnancy: Part II: Common Medical Conditions Complicating Pregnancy and Puerperium

The first of this two-part series on critical illness in pregnancy dealt with obstetric disorders. In Part II, medical conditions that commonly affect pregnant women or worsen during pregnancy are discussed. ARDS occurs more frequently in pregnancy. Strategies commonly used in nonpregnant patients, including permissive hypercapnia, limits for plateau pressure, and prone positioning, may not be acceptable, especially in late pregnancy. Genital tract infections unique to pregnancy include chorioamnionitis, group A streptococcal infection causing toxic shock syndrome, and polymicrobial infection with streptococci, staphylococci, and Clostridium perfringens causing necrotizing vulvitis or fasciitis. Pregnancy predisposes to VTE; D-dimer levels have low specificity in pregnancy. A ventilation-perfusion scan is preferred over CT pulmonary angiography in some situations to reduce radiation to the mother's breasts. Low-molecular-weight or unfractionated heparins form the mainstay of treatment; vitamin K antagonists, oral factor Xa inhibitors, and direct thrombin inhibitors are not recommended in pregnancy. The physiologic hyperdynamic circulation in pregnancy worsens many cardiovascular disorders. It increases risk of pulmonary edema or arrhythmias in mitral stenosis, heart failure in pulmonary hypertension or aortic stenosis, aortic dissection in Marfan syndrome, or valve thrombosis in mechanical heart valves. Common neurologic problems in pregnancy include seizures, altered mental status, visual symptoms, and strokes. Other common conditions discussed are aspiration of gastric contents, OSA, thyroid disorders, diabetic ketoacidosis, and cardiopulmonary arrest in pregnancy. Studies confined to pregnant women are available for only a few of these conditions. We have, therefore, reviewed pregnancy-specific adjustments in the management of these disorders.

Influenza Illness in Pregnant Indian Women: A Cross-Sectional Study

Data about burden of influenza in pregnancy in India are scant. In order to assess the contribution of influenza to acute respiratory illness (ARI) in pregnancy, 266 north Indian pregnant females with febrile ARI were studied from December 2014 to May 2015. Twin nasopharyngeal/oropharyngeal swabs were obtained and tested for influenza viruses by RT-PCR. Fifty (18.8%) patients tested positive for influenza (A/H1N1pdm09 in 41, A/H3N2 in 8, and influenza B Yamagata in 1). Rigors, headache, and a family history of ARI were significantly more frequent in influenza positive patients. Oseltamivir and supportive therapy were administered to all confirmed cases. Nine influenza positive cases needed hospitalization for their respiratory illness, and 5 developed respiratory failure. Of these, 4 (3 in third trimester) succumbed to their illness. We conclude that influenza viruses are a cause of significant morbidity and mortality among pregnant females with ARI in north India. As such, appropriate preventive strategies of influenza vaccination and early initiation of antiviral therapy during illness are stressed.

Clinical chorioamnionitis at term V: umbilical cord plasma cytokine profile in the context of a systemic maternal inflammatory response

OBJECTIVE

Microbial invasion of the fetus due to intra-amniotic infection can lead to a systemic inflammatory response characterized by elevated concentrations of cytokines in the umbilical cord plasma/serum. Clinical chorioamnionitis represents the maternal syndrome often associated with intra-amniotic infection, although other causes of this syndrome have been recently described. The objective of this study was to characterize the umbilical cord plasma cytokine profile in neonates born to mothers with clinical chorioamnionitis at term, according to the presence or absence of bacteria and/or intra-amniotic inflammation.

MATERIALS AND METHODS

A cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=38; cases) and those with spontaneous term labor without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) and amniotic fluid interleukin (IL)-6 concentration into three groups: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. A fetal inflammatory response syndrome (FIRS) was defined as an umbilical cord plasma IL-6 concentration >11 pg/mL. The umbilical cord plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) Neonates born to mothers with clinical chorioamnionitis at term (considered in toto) had significantly higher median umbilical cord plasma concentrations of IL-6, IL-12p70, IL-16, IL-13, IL-4, IL-10 and IL-8, but significantly lower interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF)-α concentrations than neonates born to mothers with spontaneous term labor without clinical chorioamnionitis; 2) neonates born to mothers with clinical chorioamnionitis at term but without intra-amniotic inflammation had higher concentrations of IL-6, IL-12p70, IL-13, IL-4, IL-5, and IL-8, but lower IFN-γ, than neonates not exposed to clinical chorioamnionitis, suggesting that maternal fever in the absence of intra-amniotic inflammation leads to a change in the fetal cytokine network; 3) there were significant, positive correlations between maternal and umbilical cord plasma IL-6 and IL-8 concentrations (IL-6: Spearman correlation=0.53; P<0.001; IL-8: Spearman correlation=0.42; P<0.001), consistent with placental transfer of cytokines; 4) an elevated fetal plasma IL-6 (>11 pg/mL), the diagnostic criterion for FIRS, was present in 21% of cases (8/38), and all these neonates were born to mothers with proven intra-amniotic infection; and 5) FIRS was associated with a high concentration of umbilical cord plasma IL-8, IL-10 and monocyte chemoattractant protein (MCP)-1.

CONCLUSIONS

Neonates born to mothers with clinical chorioamnionitis at term had higher concentrations of umbilical cord plasma cytokines than those born to mothers without clinical chorioamnionitis. Even neonates exposed to clinical chorioamnionitis but not to intra-amniotic inflammation had elevated concentrations of multiple cytokines, suggesting that intrapartum fever alters the fetal immune response.

Population pharmacokinetics of oseltamivir in non-pregnant and pregnant women

AIMS

Physiological changes in pregnancy are expected to alter the pharmacokinetics of various drugs. The objective of this study was to evaluate systematically the pharmacokinetics of oseltamivir (OS), a drug used in the treatment of influenza during pregnancy.

METHODS

A multicentre steady-state pharmacokinetic study of OS was performed in 35 non-pregnant and 29 pregnant women. Plasma concentration-time profiles were analyzed using both non-compartmental and population pharmacokinetic modelling (pop PK) and simulation approaches. A one compartment population pharmacokinetic model with first order absorption and elimination adequately described the pharmacokinetics of OS.

RESULTS

The systemic exposure of oseltamivir carboxylate (OC, active metabolite of OS) was reduced approximately 30 (19-36)% (P < 0.001) in pregnant women. Pregnancy significantly (P < 0.001) influenced the clearance (CL/F) and volume of distribution (V/F) of OC. Both non-compartmental and population pharmacokinetic approaches documented approximately 45 (23-62)% increase in clearance (CL/F) of OC during pregnancy.

CONCLUSION

Based on the decrease in exposure of the active metabolite, the currently recommended doses of OS may need to be increased modestly in pregnant women in order to achieve comparable exposure with that of non-pregnant women.

Review on the effects of influenza vaccination during pregnancy on preterm births

Pregnant women are considered to be susceptible to severe influenza illness and are recommended as a priority group to be targeted for influenza vaccination in countries with vaccination programs. Increased rates of poor birth outcomes have also been temporally associated with influenza infection, especially when pandemics strains emerge. Even though the primary purpose for influenza vaccination during pregnancy is to decrease the risk of influenza infection in the women, other potential benefits include protection of their young infants against influenza illness and possibly improving birth outcomes. The 2009 influenza A/H1N1 pandemic highlighted the importance of influenza vaccination during pregnancy, after pregnant women were identified as a group with heightened morbidity and mortality during the pandemic. A few studies conducted before the 2009/10 season and a large number of reports during and after the 2009 pandemic have assessed the association between maternal influenza vaccination and birth outcomes. Although these studies indicate that influenza vaccination is safe for both the mother and the fetus, there are conflicting data on the effect of vaccination in improving preterm birth rates. We reviewed the 2 published randomized control trials and other observational studies that explored the relationship between maternal influenza vaccination and preterm births.

The Global Influenza Initiative recommendations for the vaccination of pregnant women against seasonal influenza

There is a heavy disease burden due to seasonal influenza in pregnant women, their fetuses, and their newborns. The main aim of this study was to review and analyze current evidence on safety, immunogenicity, and clinical benefits of the inactivated influenza vaccine (IIV) in pregnant women. Current evidence shows that in pregnant women, the seasonal and pandemic IIVs are safe and well tolerated. After vaccination, pregnant women have protective concentrations of anti-influenza antibodies, conferring immunogenicity in newborns. The best evidence, to date, suggests that influenza vaccination confers clinical benefits in both pregnant women and their newborns. Vaccination with either the seasonal or pandemic vaccine has been shown to be cost-effective in pregnancy. There are scarce data from randomized clinical trials; fortunately, new phase 3 clinical trials are under way. In the Northern and Southern Hemispheres, data suggest that the greatest clinical benefit for infants occurs if the IIV is administered within the first weeks of availability of the vaccine, at the beginning of the influenza season, regardless of the pregnancy trimester. The optimal timing to vaccinate pregnant women who live in tropical regions is unclear. Based on evaluation of the evidence, the Global Influenza Initiative (GII) recommends that to prevent seasonal influenza morbidity and mortality in infants and their mothers, all pregnant women, regardless of trimester, should be vaccinated with the IIV. For countries where vaccination against influenza is starting or expanding, the GII recommends that pregnant women have the highest priority.

Demographic and clinical characteristics of deaths associated with influenza A(H1N1) pdm09 in Central America and Dominican Republic 2009-2010

BACKGROUND

The demographic characteristics of pandemic influenza decedents among middle and low-income tropical countries are poorly understood. We explored the demographics of persons who died with influenza A (H1N1)pdm09 infection during 2009-2010, in seven countries in the American tropics.

METHODS

We used hospital-based surveillance to identify laboratory-confirmed influenza deaths in Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama and Dominican Republic. An influenza death was defined as a person who died within two weeks of a severe acute respiratory infection (SARI) defined as sudden onset of fever >38 °C, cough or sore-throat, and shortness of breath, or difficulty breathing requiring hospitalization, and who tested positive for influenza A (H1N1)pdm09 virus by real time polymerase chain reaction. We abstracted the demographic and clinical characteristics of the deceased from their medical records.

RESULTS

During May 2009-June 2010, we identified 183 influenza deaths. Their median age was 32 years (IQR 18-46 years). One-hundred and one (55 %) were female of which 20 (20 %) were pregnant and 7 (7 %) were in postpartum. One-hundred and twelve decedents (61 %) had pre-existing medical conditions, (15 % had obesity, 13 % diabetes, 11 % asthma, 8 % metabolic disorders, 5 % chronic obstructive pulmonary disease, and 10 % neurological disorders). 65 % received oseltamivir but only 5 % received it within 48 h of symptoms onset.

CONCLUSIONS

The pandemic killed young adults, pregnant women and those with pre-existing medical conditions. Most sought care too late to fully benefit from oseltamivir. We recommend countries review antiviral treatment policies for people at high risk of developing complications.

2010 A(H1N1) vaccination in pregnant women in Brazil: identifying coverage and associated factors

We studied vaccination coverage and its associated factors in the 2010 pandemic influenza vaccination of Brazilian pregnant women. A cross-sectional study of pregnant women who had given birth was performed in a municipality in southern Brazil, in 2010. Data about vaccination against A(H1N1) and sociodemographic characteristics, morbidities and prenatal care were collected. Statistical analysis was performed using a Poisson regression. Coverage was 77.4%. Most were vaccinated in the public sector (97.6%) and in the second trimester (47%). Associated factors that increased vaccination were marriage, older age, first income quartile, prenatal care and influenza before pregnancy. Education and skin color were not significantly associated with vaccination. The vaccination campaign was extensive and exhibited no inequality. Prenatal care was the factor that most affected vaccination coverage, reflecting its importance for vaccination campaign success.