Seasonal and 2009 pandemic influenza A (H1N1) virus infection during pregnancy: a population-based study of hospitalized cases

Management of influenza - updated Swedish guidelines for antiviral treatment

Influenza causes seasonal epidemics of respiratory infection in all parts of the world. Manifestations of influenza range from mild upper to severe lower respiratory tract infection. Medical risk groups are defined by factors predisposing for development of severe disease and are recommended annual vaccination as a protective measure. The previous Swedish treatment guidelines for influenza were issued in 2011, and a review of current evidence was deemed relevant. An important reason to revisit the guidelines is the recent approval of a novel drug for influenza treatment, baloxavir. Updated Swedish evidence-based guidelines created by a group of experts from various research areas, for the management of influenza are presented here. The work has been made in collaboration with the Public Health Agency of Sweden and the Swedish Reference Group for AntiViral therapy (RAV). The updated guidelines include guidelines for diagnostics, treatment and prophylaxis in special groups, including management of pregnant women and children with influenza. A new section about infection control has been added. Pharmacological treatment is covered in detail with regards to indication and dosage. Additionally, drug resistance and environmental aspects are discussed.

Multi-decade national cohort identifies adverse pregnancy and birth outcomes associated with acute respiratory illness hospitalisations during the influenza season

BACKGROUND

Despite the World Health Organization (WHO) recommendation that pregnant women be prioritised for seasonal influenza vaccination, coverage in the Western Pacific Region remains low. Our goal was to provide additional data for the Western Pacific Region about the value of maternal influenza vaccination to pregnant women and their families.

METHODS

We conducted a 16-year retrospective cohort to evaluate risks associated with influenza-associated maternal acute respiratory infection (ARI) in New Zealand. ARI hospitalisations during the May to September influenza season were identified using select ICD-10-AM primary and secondary discharge codes from chapter J00-J99 (diseases of the respiratory system). Cox proportional hazards models were used to calculate crude and adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs).

RESULTS

We identified 822,391 pregnancies among New Zealand residents between 2003 and 2018; 5095 (0.6%) had ≥1 associated ARI hospitalisation during the influenza season; these pregnancies were at greater risk of preterm birth (aHR 1.50, 95% CI 1.39-1.61) and low birthweight (aHR 1.64, 95% CI 1.51-1.79) than pregnancies without such hospitalisations. We did not find an association between maternal ARI hospitalisation and fetal death (aHR 0.96, 95% CI 0.69-1.34) during the influenza season. Maternal influenza vaccination was associated with reduced risk of preterm birth (aHR 0.79, 95% CI 0.77-0.82), low birthweight (aHR 0.87, 95% CI 0.83-0.90) and fetal death (aHR 0.50%, 95% CI 0.44-0.57).

CONCLUSION

In this population-based cohort, being hospitalised for an ARI during the influenza season while pregnant was a risk factor for delivering a preterm or a low birthweight infant and vaccination reduced this risk.

Multiprofessional perinatal care in a pregnant patient with acute respiratory distress syndrome due to COVID-19

Background

The coronavirus disease (COVID-19) pandemic has caused ongoing challenges in health services worldwide. Despite the growing body of literature on COVID-19, reports on perinatal care in COVID-19 cases are limited.

Case presentation

We describe a case of severe acute respiratory distress syndrome (ARDS) in a 36-year-old G5/P2 pregnant woman with morbid obesity, confirmed severe acute respiratory syndrome coronavirus 2 infection, and fulminant respiratory failure. At 28^+ 1 gestational weeks, the patient delivered an uninfected newborn. Using ImmunoCAP ISAC® technology, we found no immunoglobulin (Ig) M antibodies, suggesting that no mother-to-child viral transmission occurred during pregnancy or delivery. The maternal respiratory state improved rapidly after delivery; both maternal and neonatal outcomes were encouraging given the early gestational age and fulminant course of respiratory failure in our patient.

Conclusions

The management of ARDS in pregnant women with COVID-19 is complex and requires an individualized, multidisciplinary approach, while considering maternal and fetal outcomes.

Coverage and Timing of Influenza Vaccination Among Privately Insured Pregnant Women in the United States, 2010-2018

OBJECTIVE

Pregnant women are at increased risk of serious complications from influenza and are recommended to receive an influenza vaccination during pregnancy. The objective of this study was to assess trends, timing patterns, and associated factors of influenza vaccination among pregnant women.

METHODS

We used 2010-2018 MarketScan data on 1 286 749 pregnant women aged 15-49 who were privately insured to examine trends and timing patterns of influenza vaccination coverage. We examined descriptive statistics and identified factors associated with vaccination uptake by using multivariate log-binomial and Cox proportional hazard models.

RESULTS

In-plan influenza vaccination coverage before delivery increased from 22.0% during the 2010-2011 influenza season to 33.2% during the 2017-2018 influenza season. About two-thirds of vaccinated women received the vaccine in September or October during each influenza season. For women who delivered in September through May, influenza vaccination coverage increased rapidly at the beginning of influenza season and flattened after October. For women who delivered in June through August, influenza vaccination coverage increased gradually until February and flattened thereafter. Most vaccinated women who delivered before January received the vaccine in the third trimester. Increased likelihood of being vaccinated was associated with age 31-40, living in a metropolitan statistical area, living outside the South, enrollment in a consumer-driven or high-deductible health plan, being spouses or dependents of policy holders, and delivery in November through January.

CONCLUSIONS

Despite increases during the past several years, vaccination uptake is still suboptimal, particularly after October. Health care provider education on timing of vaccination and recommendations throughout influenza seasons are needed to improve influenza vaccination coverage among pregnant women.

The effect of influenza virus infection on pregnancy outcomes: A systematic review and meta-analysis of cohort studies

BACKGROUND

Adverse pregnancy outcomes are risk factors for neonatal mortality and morbidity. While some studies have demonstrated notable associations between influenza and adverse pregnancy outcomes, the findings have contrasted with other studies. This meta-analysis was conducted to assess the effect of influenza infection on pregnancy outcomes.

METHODS

We searched PubMed, Embase, Cochrane Library and Web of Science from inception to 4 November 2020. Relative risks (RRs) with 95% confidence intervals (CIs) were pooled using random-effects or fixed-effects models.

RESULTS

A total of 17 studies involving 2,351,204 participants were included. Influenza infection increased the risk of stillbirth (RR = 3.62, 95% CI: 1.60-8.20), with no significant effect on preterm birth (RR = 1.17, 95%CI: 0.95-1.45), fetal death (RR = 0.93, 95%CI: 0.73-1.18), small for gestational age (SGA) (RR = 1.10, 95%CI: 0.98-1.24) and low birth weight (LBW) (RR = 1.88, 95%CI: 0.46-7.66). In a subgroup analysis of LBW, the association was evident in studies conducted during the 2009 H1N1 pandemic (RR = 2.28, 95%CI: 1.81-2.87), with no evidence of an association in pre-pandemic or post-pandemic studies.

CONCLUSIONS

Influenza virus infection was associated with an increased risk of stillbirth, but its effect on preterm birth, fetal death, SGA and LBW is still uncertain.

Severe Acute Respiratory Syndrome by COVID-19 in pregnant and postpartum women

Abstract Objectives: to evaluate the morbidity and mortality profile and factors associated with death due to severe acute respiratory syndrome (SARS) by COVID-19 in pregnant and postpartum women. Methods: this is a quantitative and retrospective research that analyzed the SIVEP-gripe Database (Influenza Epidemiological Surveillance Information System), from 01/01/2020 to 04/01/2021. All pregnant women and postpartum women diagnosed with SARS caused by COVID-19 in the State of Minas Gerais were included. After the descriptive analysis of the hospitalizations profile, the association between different exposure variables and the occurrence of death was evaluated. Results: of the 227 records obtained, 94.3% required hospitalization. Among hospitalizations in the Intensive Care Unit, 29.8% used invasive ventilatory support. Fifteen deaths were recorded. The most frequent clinical manifestations were: cough and fever; the predominant comorbidities were cardiovascular disease and diabetes mellitus. The variables “ICU stay”, “use of ventilatory support” and “heart disease” were associated with the occurrence of deaths. Conclusions: hospitalization was necessary for most pregnant women with SARS and the presence of previous heart disease increased the risk of death. Knowing the SARS morbidity and mortality profile is important in the definition of public health strategies aimed at reducing the impacts of COVID-19 during pregnancy and the puerperium.

Role of Inflammation in Virus Pathogenesis during Pregnancy

Viral infections during pregnancy lead to a spectrum of maternal and fetal outcomes, ranging from asymptomatic disease to more critical conditions presenting with severe maternal morbidity, stillbirth, preterm birth, intrauterine growth restriction, and fetal congenital anomalies, either apparent at birth or later in life. In this article, we review the pathogenesis of several viral infections that are particularly relevant in the context of pregnancy and intrauterine inflammation. Understanding the diverse mechanisms employed by viral pathogens as well as the repertoire of immune responses induced in the mother may help to establish novel therapeutic options to attenuate changes in the maternal-fetal interface and prevent adverse pregnancy outcomes.

Clinical features of pregnant women in Iran who died due to COVID-19

Background

To evaluate the clinical presentation of pregnant women in Iran who died due to COVID‐19.

Methods

Data were evaluated of pregnant women who died following a laboratory diagnosis of COVID‐19. The data were obtained from electronic medical records. Additionally, a questionnaire was completed for each patient, including demographic, clinical, laboratorial, imaging, and treatment data. In case of missing information, a member of the research team contacted the first‐degree relatives via phone.

Results

Of 32 pregnant women who tested positive for COVID‐19, 15 were enrolled into the study (mean age 30.0 ± 5.0 years). The mean time from first symptoms to death was 12 ± 7.0 days. Pre‐existing comorbidities were seen in six patients. The main presentations at admission were fatigue and coughing, but most of the women had a fever below 38 °C. Increased white blood cell count and neutrophils were noticeable. A significant drop of saturation of O₂ with ground glass and consolidation seen in both lungs were prominent. The most common complications were acute respiratory distress syndrome followed by respiratory failure.

Conclusion

Computed tomography findings, O₂ pressure, and regular blood assessment may be considered suitable indicators for the surveillance of patients.

O₂ pressure, computed tomography findings, and complete blood count differential at admission are important items for predicting the outcome and surveillance of pregnant women.

Contemporary Issues in Women's Health

Clinical characteristics and outcomes of pregnant women with COVID‐19 in Wuhan, China;

SARS‐CoV‐2 infection and pregnancy.

Herpes simplex virus type 2 IgG antibodies in sera of umbilical cord as a proxy for placental infection in asymptomatic pregnant women

PROBLEM

Herpes simplex virus type 2 (HSV-2) infection is one of the most prevalent diseases worldwide and is mainly sexually transmitted. When infecting pregnant women, HSV-2 is able to infect the placenta, can reach the fetus, and may affect the fetal development. We sought to determine the prevalence of HSV-2 infection and reactivation in asymptomatic pregnant women, the correlation between IgG in the maternal circulation and cord blood, and the correlation between circulating IgG, placental, and newborn infection (blood cord).

METHOD OF STUDY

Serum samples and placental tissues from pregnant women and umbilical cord blood samples from their newborns were collected. Anti-HSV-2 antibodies were identified by ELISA, and HSV-2 DNA was detected by nested PCR.

RESULTS

The seropositivity of IgG in pregnant women was 29.7% and IgM was detected in 1 woman (0.5%). In the umbilical cord of newborns, 33.1% were IgG-positive and IgM was detected in 2 samples (1.5%). A positive correlation between HSV-2 IgG titers in serum from pregnant women and cord blood samples was found (r = .36, P = .001). A difference between the positive and negative placental groups (maternal side) was found in titers of IgG in sera of umbilical cord, which were significantly higher in the positive placental group (P = .004).

CONCLUSION

We describe for the first time that newborns from mothers with HSV-2 placental infection have higher IgG titers in sera of umbilical cord, suggesting IgGs antibodies can be indicative of placental viral infection in asymptomatic women.

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.

Risks associated with viral infections during pregnancy

Despite the prevalence of viral infections in the American population, we still have a limited understanding of how they affect pregnancy and fetal development. Viruses can gain access to the decidua and placenta by ascending from the lower reproductive tract or via hematogenous transmission. Viral tropism for the decidua and placenta is then dependent on viral entry receptor expression in these tissues as well as on the maternal immune response to the virus. These factors vary by cell type and gestational age and can be affected by changes to the in utero environment and maternal immunity. Some viruses can directly infect the fetus at specific times during gestation, while some only infect the placenta. Both scenarios can result in severe birth defects or pregnancy loss. Systemic maternal viral infections can also affect the pregnancy, and these can be especially dangerous, because pregnant women suffer higher virus-associated morbidity and mortality than do nonpregnant counterparts. In this Review, we discuss the potential contributions of maternal, placental, and fetal viral infection to pregnancy outcome, fetal development, and maternal well-being.

Cutting Edge: Fetal/Placental Type I IFN Can Affect Maternal Survival and Fetal Viral Load during Viral Infection

Pregnant women have greater mortality and complications associated with viral infections compared with the general population, but the reason for the increased susceptibility is not well defined. Placenta type I IFN is an important immune modulator and protects the pregnancy. We hypothesized that loss of placental IFN affects the regulation of the maternal immune system, resulting in the differential response to infections observed in pregnancy. Pregnant mice lacking the IFN-α/β receptor (IFNAR) became viremic and had higher mortality compared with nonpregnant animals. Notably, an embryo with functional IFN signaling alone was sufficient to rescue the pregnant IFNAR-/- dam from virus-associated demise. Placental IFN was also an important regulator of viral replication in placental tissue and significantly affected viral transmission to the fetus. These findings highlight the role of fetal/placental IFN in the modulation of viral infection in the mother and fetus.

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.

The US Influenza Hospitalization Surveillance Network

In 2003, surveillance for influenza in hospitalized persons was added to the Centers for Disease Control and Prevention Emerging Infections Program network. This surveillance enabled monitoring of the severity of influenza seasons and provided a platform for addressing priority questions associated with influenza. For enhanced surveillance capacity during the 2009 influenza pandemic, new sites were added to this platform. The combined surveillance platform is called the Influenza Hospitalization Surveillance Network (FluSurv-NET). FluSurv-NET has helped to determine the risk for influenza-associated illness in various segments of the US population, define the severity of influenza seasons and the 2009 pandemic, and guide recommendations for treatment and vaccination programs.

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.

Improving influenza and Tdap vaccination during pregnancy: A cluster-randomized trial of a multi-component antenatal vaccine promotion package in late influenza season

BACKGROUND

Evidence-based interventions to improve influenza vaccine coverage among pregnant women are needed, particularly among those who remain unvaccinated late into the influenza season. Improving rates of antenatal tetanus, diphtheria and acellular pertussis (Tdap) vaccination is also needed.

PURPOSE

To test the effectiveness of a practice-, provider-, and patient-focused influenza and Tdap vaccine promotion package on improving antenatal influenza and Tdap vaccination in the obstetric setting.

METHODS

A cluster-randomized trial among 11 obstetric practices in Georgia was conducted in 2012-2013. Intervention practices adopted the intervention package that included identification of a vaccine champion, provider-to-patient talking points, educational brochures, posters, lapel buttons, and iPads loaded with a patient-centered tutorial. Participants were recruited from December 2012-April 2013 and included 325 unvaccinated pregnant women in Georgia. Random effects regression models were used to evaluate primary and secondary outcomes.

RESULTS

Data on antenatal influenza and Tdap vaccine receipt were obtained for 300 (92.3%) and 291 (89.5%) women, respectively. Although antenatal influenza and Tdap vaccination rates were higher in the intervention group than the control group, improvements were not significant (For influenza: risk difference (RD)=3.6%, 95% confidence interval (CI): -4.0%, 11.2%; for Tdap: RD=1.3%, 95% CI: -10.7%, 13.2%). While the majority of intervention package components were positively associated with antenatal vaccine receipt, a provider's recommendation was the factor most strongly associated with actual receipt, regardless of study group or vaccine.

CONCLUSIONS

The intervention package did not significantly improve antenatal influenza or Tdap vaccine coverage. More research is needed to determine what motivates women remaining unvaccinated against influenza late into the influenza season to get vaccinated. Future research should quantify the extent to which clinical interventions can bolster a provider's recommendation for vaccination. This study is registered with clinicaltrials.gov, study ID NCT01761799.

Influenza A(H1N1)pdm09 infection in pregnant and non-pregnant women hospitalized in Singapore, May - December 2009

OBJECTIVES

The aim of this study was to compare the demographic and clinical characteristics of pregnant women and non-pregnant women of childbearing age hospitalized with laboratory-confirmed influenza A(H1N1)pdm09 infection in Singapore, and to assess whether pregnancy was a risk factor associated with the development of influenza-related complications.

STUDY DESIGN

Retrospective observational study.

METHODS

We retrospectively identified and collected information from available medical records of all women admitted to three tertiary hospitals between 26 May 2009 and 31 December 2009 with laboratory-confirmed influenza A(H1N1)pdm09 infection who were either pregnant or non-pregnant and of childbearing age between 15 and 50 years.

RESULTS

A total of 222 women, of whom 81 (36.5%) were pregnant, were hospitalized during the study period. Pregnant women were significantly more likely to be hospitalized with influenza A(H1N1)pdm09 infection than non-pregnant women of childbearing age (relative risk 26.3; 95% confidence interval: 20.1-34.6). Among those hospitalized, the proportion of pregnant women having at least one underlying medical condition that could predispose them to influenza-related complications was significantly lower than that of non-pregnant women (32.1% versus 56.0%, P < 0.001). The median time from onset of symptoms to administration of anti-viral drugs was significantly shorter among pregnant women than among non-pregnant women (three days versus five days, P < 0.001). The median length of stay in hospital was also significantly shorter among pregnant women than that of non-pregnant women (two days versus three days, P = 0.002). About 4.9% of pregnant women developed influenza-related complications, compared with 12.8% among non-pregnant women (P = 0.066).

CONCLUSIONS

Pregnant women with influenza A(H1N1)pdm09 infection were at a higher risk of hospitalization. Upon hospitalization, they were not at a higher risk of developing influenza-related complications.

Maternal immunization. Clinical experiences, challenges, and opportunities in vaccine acceptance

Maternal immunization holds tremendous promise to improve maternal and neonatal health for a number of infectious conditions. The unique susceptibilities of pregnant women to infectious conditions, as well as the ability of maternally-derived antibody to offer vital neonatal protection (via placental transfer), together have produced the recent increased attention on maternal immunization. The Advisory Committee on Immunization Practices (ACIP) currently recommends 2 immunizations for all pregnant women lacking contraindication, inactivated Influenza and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap). Given ongoing research the number of vaccines recommended during pregnancy is likely to increase. Thus, achieving high vaccination coverage of pregnant women for all recommended immunizations is a key public health enterprise. This review will focus on the present state of vaccine acceptance in pregnancy, with attention to currently identified barriers and determinants of vaccine acceptance. Additionally, opportunities for improvement will be considered.

Socioeconomic burden of influenza in the Republic of Korea, 2007-2010

Background

Although the socioeconomic burden of 2009 pandemic influenza A (H1N1) was considerable, no reliable estimates have been reported. Our aim was to compared medical costs and socioeconomic burden resulting from pandemic influenza A (H1N1) 2009 with that of previous seasonal influenza.

Methods

We estimated the medical costs and socioeconomic burden of influenza from May 2007 to April 2010. We used representative national data sources(data from the Health Insurance Review Agency, the National Health Insurance Corporation, the Korea Centers for Disease Control and Prevention, and the Korean National Statistics Office) including medical utilization, prescription of antivirals, and vaccination. Uncertainty of data was explored through sensitivity analysis using Monte Carlo simulation.

Results

Compared with the seasonal influenza, total medical costs (US$291.7 million) associated with pandemic (H1N1) 2009 increased more than 37-fold. Compared with the 2007–2008 season, outpatient diagnostic costs (US$135.3 million) were 773 times higher in the 2009–2010 season, and the mean diagnostic cost per outpatient visit was 58.8 times higher. Total socioeconomic burden of pandemic (H1N1) 2009 was estimated at US$1581.3 million (10%–90%: US$1436.0–1808.3 million) and those of seasonal influenza was estimated at US$44.7 million (10%–90%: US$32.4–57.9 million) in 2007–2008 season and US$42.3 million (10%–90%: US$31.5–53.8 million) in 2008–2009 season. Indirect costs accounted for 56.0% of total costs in pandemic (H1N1) 2009, and 66.48–68.09% in seasonal influenza. The largest contributors to total burden were productivity losses of caregiver in pandemic (H1N1) 2009, and productivity losses due to morbidity of outpatient in seasonal influenza.

Conclusions

In the Republic of Korea, socioeconomic burden of pandemic (H1N1) 2009 were considerably higher than burden of the previous two influenza seasons, primarily because of high diagnostic costs and longer sick leave.

Influenza vaccination acceptance among diverse pregnant women and its impact on infant immunization

OBJECTIVE

We examined pregnant women's likelihood of vaccinating their infants against seasonal influenza via a randomized message framing study. Using Prospect Theory, we tested gain- and loss-frame message effects and demographic and psychosocial correlates of influenza immunization intention. We also explored interactions among pregnant women who viewed "Contagion" to understand cultural influences on message perception.

METHODS

Pregnant women ages 18-50 participated in a randomized message framing study from September 2011 through May 2012 that included exposure to intervention or control messages, coupled with questionnaire completion. Venue-based sampling was used to recruit racial and ethnic minority female participants at locations throughout Atlanta, Georgia. Bivariate and multivariate analyses were conducted to evaluate key outcomes.

RESULTS

The study population (n = 261) included many lower income (≤ $20,000/yearly household earnings) pregnant participants (69.2%, n = 171) inclusive of Black/African Americans (88.5%, n = 230), Hispanic/Latinas (7.3%, n = 19), and Other/Multicultural women (4.2%, n = 11). Both gain [OR = 2.13, 90% CI: (1.120, 4.048)] and loss-frame messages [OR = 2.02, 90% CI: (1.083, 3.787)] were significantly associated with infant influenza vaccination intention compared with the control condition. Intention to immunize against influenza during pregnancy had a strong effect on intent to immunize infants [OR = 10.83, 90%CI: (4.923, 23.825)]. Those who had seen the feature film "Contagion" (n = 54, 20.69%) viewed gain- and loss-framed messages as appealing (x (2) = 6.03, p = 0.05), novel (x (2) = 6.24, p = 0.03), and easy to remember (x (2) = 16.33, P = 0.0003).

CONCLUSIONS

In this population, both gain- and loss-framed messages were positively associated with increased maternal intent to immunize infants against influenza. Message resonance was enhanced among those who saw the film "Contagion." Additionally, history of immunization was strongly associated with infant immunization intention. :

Maternal and neonatal outcomes among pregnant women with 2009 pandemic influenza A(H1N1) illness in Florida, 2009-2010: a population-based cohort study

INTRODUCTION

Pregnant women have been identified as a high risk group for severe illness with 2009 pandemic influenza A(H1N1) virus infection (pH1N1). Obesity has also been identified as a risk factor for severe illness, though this has not been thoroughly assessed among pregnant women. The objectives of this study were to provide risk estimates for adverse maternal and neonatal outcomes associated with pH1N1 illness during pregnancy and to assess the role of obesity in these outcomes.

METHODS

We established a retrospective population-based cohort of all live births occurring in Florida during the first 15 months of the pandemic. Illness with pH1N1 during pregnancy was ascertained through record linkage with the Florida state notifiable disease surveillance database. Data from the birth record, including pre-pregnancy body mass index, were analyzed to assess risk of adverse outcomes associated with pH1N1 illness.

RESULTS

A total of 194 women were identified through surveillance with pH1N1 illness during pregnancy. Children born to women with pH1N1 illness during pregnancy were at increased risk for low birth weight [OR (95%CI): 1.78 (1.11-2.860)], premature birth [2.21 (1.47-3.330)], and infant death [4.46 (1.80-11.00)], after adjusting for other factors. Women with pH1N1 illness during pregnancy were at increased risk for severe outcomes including admission to an intensive care unit. Obesity was an observed risk factor, both for the more severe pH1N1 illness detected through surveillance, and for severe maternal outcomes.

CONCLUSIONS

Case-patients in this analysis likely represent the most severely ill subset of all women infected with pH1N1 during pregnancy, limiting the generalizability of these findings to more severely ill patients rather than influenza infection in general. Nevertheless, these results suggest that more severe pH1N1 illness during pregnancy is associated with adverse neonatal outcomes and that pregnant women should continue to be targeted for appropriate prophylaxis and early treatment.

Impact of the fall 2009 influenza A(H1N1)pdm09 pandemic on US hospitals

BACKGROUND

Understanding how hospitals functioned during the 2009 influenza A(H1N1)pdm09 pandemic may improve future public health emergency response, but information about its impact on US hospitals remains largely unknown.

RESEARCH DESIGN

We matched hospital and emergency department (ED) discharge data from the Agency for Healthcare Research and Quality (AHRQ) Healthcare Cost and Utilization Project with community-level influenza-like illness activity during each hospital's pandemic period in fall 2009 compared with a corresponding calendar baseline period. We compared inpatient mortality for sentinel conditions at high-surge versus nonsurge hospitals.

RESULTS

US hospitals experienced a doubling of pneumonia and influenza ED visits during fall 2009 compared with prior years, along with an 18% increase in overall ED visits. Although no significant increase in total inpatient admissions occurred overall, approximately 10% of all study hospitals experienced high surge, associated with higher acute myocardial infarction and stroke case fatality rates. These hospitals had similar characteristics to other US hospitals except that they had higher mortality for acute cardiac illnesses before the pandemic. After adjusting for 2008 case fatality rates, the association between high-surge hospitals and increased mortality for acute myocardial infarction and stroke patients persisted.

CONCLUSIONS

The fall 2009 pandemic period substantially impacted US hospitals, mostly through increased ED visits. For a small proportion of hospitals that experienced a high surge in inpatient admissions, increased mortality from selected clinical conditions was associated with both prepandemic outcomes and surge, highlighting the linkage between daily hospital operations and disaster preparedness.

Common respiratory issues in ambulatory obstetrics

This article reviews the diagnosis and management of the most common respiratory conditions complicating pregnancy--asthma and influenza. We also review strategies for smoking cessation in pregnancy as, in addition to exacerbating all other pulmonary conditions, smoking is the most modifiable risk factor for poor pregnancy outcome. Moreover, the obstetrician frequently encounters each of these conditions in the ambulatory setting. A thorough knowledge of the normal pregnancy-induced physiological respiratory changes combined with a comprehensive understanding of how to manage these conditions, will provide the obstetrician with the armamentarium needed to optimize health outcomes for mothers and their fetuses.

Acceptance and rejection of influenza vaccination by pregnant women in southern Iran: physicians' role and barriers

OBJECTIVE

Vaccination provides the most effective protection against maternal, fetal and neonatal complications of influenza infection. This study aimed to determine the uptake rate of influenza vaccination including 2009 pandemic H1N1 influenza and seasonal influenza vaccination and the reasons for acceptance or rejection among pregnant women.

RESULT

Mean age of the 416 pregnant women enrolled in this study was 27.06 ± 5.27 y. Only 25 (6%) of 397 women had history of vaccination. Of 383 (92.06%) pregnant women who had rejected vaccination, 116 (30.28%) declared that they lacked information about influenza vaccination and 44 (11.48%) felt that they did not need vaccination. Concerns about the safety of influenza vaccination were reported by only 2 women (0.52%). Of the 25 (6%) pregnant women who were vaccinated against influenza, 15 (60%) accepted because of advice they received from persons other than physicians, 5 (20%) believed that influenza vaccination is necessary for everyone, and 3 (12%) accepted because of a history of frequent influenza virus infections in previous years.

METHOD

This questionnaire based study was conducted at obstetrics and maternity hospitals affiliated with Shiraz University of Medical Sciences, Shiraz, Iran. Pregnant women were interviewed individually and privately. SPSS was used for data analysis.

CONCLUSION

Most of the unvaccinated and vaccinated pregnant women lacked sufficient knowledge about influenza. Education of pregnant women about influenza vaccination and encouragement from physicians may have a remarkable effect on turning poor compliance into high flu vaccination uptake among pregnant women.

Viral invasion of the amniotic cavity (VIAC) in the midtrimester of pregnancy

INTRODUCTION

The prevalence of viral infections in the amniotic fluid (AF) has not yet been ascertained. The aim of this study was to determine the prevalence of specific viral nucleic acids in the AF and its relationship to pregnancy outcome.

STUDY DESIGN

From a cohort of 847 consecutive women undergoing midtrimester amniocentesis, 729 cases were included in this study after exclusion of documented fetal anomalies, chromosomal abnormalities, unavailability of AF specimens and clinical outcomes. AF specimens were tested by quantitative real-time PCR for the presence of genome sequences of the following viruses: adenoviruses, herpes simplex virus (HSV), varicella zoster virus (VZV), human herpesvirus 6 (HHV6), human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), parvovirus B19 and enteroviruses. Viral nucleic acid testing was also performed in maternal blood and cord blood in the population of women in whom AF was positive for viruses and in a control group of 29 women with AF negative for viral nucleic acids. The relationship between the presence of viruses and pregnancy and neonatal outcome was examined. The correlation between the presence of nucleic acids of viruses in the AF and the concentration of the cytokine interleukin-6 (IL-6) and the T cell chemokine CXCL-10 (or IP-10) in AF and maternal blood were analyzed.

RESULTS

Viral genome sequences were found in 16 of 729 (2.2%) AF samples. HHV6 was the most commonly detected virus (7 cases, 1.0%), followed by HCMV (6 cases, 0.8%), parvovirus B19 (2 cases, 0.3%) and EBV (1 case, 0.1%), while HSV, VZV, enteroviruses and adenoviruses were not found in this cohort. Corresponding viral DNA was also detected in maternal blood of six out of seven women with HHV6-positive AF and in the umbilical cord plasma, which was available in one case. In contrast, viral DNA was not detected in maternal blood of women with AF positive for parvovirus B19, HCMV, EBV or of women with AF negative for viruses. HHV6 genome copy number in AF and maternal blood was consistent with genomic integration of viral DNA and genetic infection in all women. There was no significant difference in the AF concentration of IL-6 and IP-10 between patients with and without VIAC. However, for HCMV, there was a significant relationship between viral copy number and IP-10 concentration in maternal blood and AF. The group of women with AF positive for viral DNA delivered at term healthy neonates without complications in 14 out of 16 cases. In one case of HHV6 infection in the AF, the patient developed gestational hypertension at term, and in another case of HHV6 infection in the AF, the patient delivered at 33 weeks after preterm premature rupture of membranes (PPROM).

CONCLUSION

Viral nucleic acids are detectable in 2.2% of AF samples obtained from asymptomatic women in the midtrimester. HHV6 was the most frequently detected virus in AF. Adenoviruses were not detected. Vertical transmission of HHV6 was demonstrated in one case.

The comparative clinical course of pregnant and non-pregnant women hospitalised with influenza A(H1N1)pdm09 infection

INTRODUCTION

The Influenza Clinical Information Network (FLU-CIN) was established to gather detailed clinical and epidemiological information about patients with laboratory confirmed A(H1N1)pdm09 infection in UK hospitals. This report focuses on the clinical course and outcomes of infection in pregnancy.

METHODS

A standardised data extraction form was used to obtain detailed clinical information from hospital case notes and electronic records, for patients with PCR-confirmed A(H1N1)pdm09 infection admitted to 13 sentinel hospitals in five clinical 'hubs' and a further 62 non-sentinel hospitals, between 11th May 2009 and 31st January 2010.Outcomes were compared for pregnant and non-pregnant women aged 15-44 years, using univariate and multivariable techniques.

RESULTS

Of the 395 women aged 15-44 years, 82 (21%) were pregnant; 73 (89%) in the second or third trimester. Pregnant women were significantly less likely to exhibit severe respiratory distress at initial assessment (OR = 0.49 (95% CI: 0.30-0.82)), require supplemental oxygen on admission (OR = 0.40 (95% CI: 0.20-0.80)), or have underlying co-morbidities (p-trend <0.001). However, they were equally likely to be admitted to high dependency (Level 2) or intensive care (Level 3) and/or to die, after adjustment for potential confounders (adj. OR = 0.93 (95% CI: 0.46-1.92). Of 11 pregnant women needing Level 2/3 care, 10 required mechanical ventilation and three died.

CONCLUSIONS

Since the expected prevalence of pregnancy in the source population was 6%, our data suggest that pregnancy greatly increased the likelihood of hospital admission with A(H1N1)pdm09. Pregnant women were less likely than non-pregnant women to have respiratory distress on admission, but severe outcomes were equally likely in both groups.

Pregnancy and pregnancy-associated hormones alter immune responses and disease pathogenesis

During pregnancy, it is evolutionarily advantageous for inflammatory immune responses that might lead to fetal rejection to be reduced and anti-inflammatory responses that promote transfer of maternal antibodies to the fetus to be increased. Hormones modulate the immunological shift that occurs during pregnancy. Estrogens, including estradiol and estriol, progesterone, and glucocorticoids increase over the course of pregnancy and affect transcriptional signaling of inflammatory immune responses at the maternal-fetal interface and systemically. During pregnancy, the reduced activity of natural killer cells, inflammatory macrophages, and helper T cell type 1 (Th1) cells and production of inflammatory cytokines, combined with the higher activity of regulatory T cells and production of anti-inflammatory cytokines, affects disease pathogenesis. The severity of diseases caused by inflammatory responses (e.g., multiple sclerosis) is reduced and the severity of diseases that are mitigated by inflammatory responses (e.g., influenza and malaria) is increased during pregnancy. For some infectious diseases, elevated inflammatory responses that are necessary to control and clear a pathogen have a negative consequence on the outcome of pregnancy. The bidirectional interactions between hormones and the immune system contribute to both the outcome of pregnancy and female susceptibility to disease.

Possible roles of proinflammatory and chemoattractive cytokines produced by human fetal membrane cells in the pathology of adverse pregnancy outcomes associated with influenza virus infection

Pregnant women are at an increased risk of influenza-associated adverse outcomes, such as premature delivery, based on data from the latest pandemic with a novel influenza A (H1N1) virus in 2009-2010. It has been suggested that the transplacental transmission of influenza viruses is rarely detected in humans. A series of our study has demonstrated that influenza virus infection induced apoptosis in primary cultured human fetal membrane chorion cells, from which a factor with monocyte differentiation-inducing (MDI) activity was secreted. Proinflammatory cytokines, such as interleukin (IL)-6, tumor necrosis factor (TNF)-α, and interferon (IFN)-β, were identified as a member of the MDI factor. Influenza virus infection induced the mRNA expression of not only the proinflammatory cytokines but also chemoattractive cytokines, such as monocyte chemoattractant protein (MCP)-1, regulated on activation, normal T-cell expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1β, IL-8, growth-regulated oncogene (GRO)-α, GRO-β, epithelial cell-derived neutrophil-activating protein (ENA)-78, and interferon inducible protein (IP)-10 in cultured chorion cells. These cytokines are postulated to associate with human parturition. This paper, therefore, reviews (1) lessons from pandemic H1N1 2009 in pregnancy, (2) production of proinflammatory and chemoattractive cytokines by human fetal membranes and their functions in gestational tissues, and (3) possible roles of cytokines produced by human fetal membranes in the pathology of adverse pregnancy outcomes associated with influenza virus infection.

Titering of 2009 pandemic H1N1 influenza virus hemagglutinin inhibition antibody in nonvaccinated pregnant women in Shiraz, Southern Iran

Influenza may cause severe complications for pregnant women. In this study antibody response against 2009 H1N1 influenza virus in pregnant women was investigated. This seroprevalance cross sectional and questionnaire based study was conducted using a convenient sampling method. Blood samples of pregnant women were checked for antibodies against 2009 H1N1 influenza virus using hemagglutination inhibition assay. An antibody titer level of ≥ 1:40 dilution was considered as the protective level. 167 (43.60%) of 383 pregnant women who participated in this study had protective antibody levels against this virus. 62 (35.63%) of 3rd trimester, 79 (46.74%) of 2nd trimester, and 21(52.50%) of 1st trimester pregnant women were immune respectively (χ2(for trend) = 8.20, p < 0.004). Lack of protective antibody level was significantly seen more in pregnant women of 3rd trimester of pregnancy (OR = 2.37, CI = 1.09-5.18). Pregnant women with higher education (OR = 1.67, CI = 1.02-2.73) and those with history of anemia (OR = 2.09, CI = 1.18-3.68) had more immunity. Older women (OR = 0.95, CI = 0.91-0.99) and those with history of psychological diseases (OR = 0.19, CI = 0.05-0.70) had less immunity. Vaccination of pregnant women, especially those who are in the higher trimesters of pregnancy, older, or less educated, against the 2009 H1N1 influenza virus should be continued.

Influenza-like illness in hospitalized pregnant and postpartum women during the 2009-2010 H1N1 pandemic

OBJECTIVE

To estimate characteristics and outcomes of pregnant and immediately postpartum women hospitalized with influenza-like illness during the 2009-2010 influenza pandemic and the factors associated with more severe illness.

METHODS

An observational cohort in 28 hospitals of pregnant and postpartum (within 2 weeks of delivery) women hospitalized with influenza-like illness. Influenza-like illness was defined as clinical suspicion of influenza and either meeting the Centers for Disease Control and Prevention definition of influenza-like illness (fever 100.0°F or higher, cough, sore throat) or a positive influenza test.

RESULTS

Of 356 women meeting eligibility criteria, 35 (9.8%) were admitted to the intensive care unit (ICU) and four (1.1%) died. Two hundred eighteen women (61.2%) were in the third trimester and 10 (2.8%) were postpartum. More than half (55.3%) were admitted in October and 25.0% in November with rapidly decreasing numbers thereafter. Antiviral therapy was administered to 10.1% of the women before hospitalization and to 88.5% during hospitalization. Factors associated with an increased likelihood of ICU admission included cigarette smoking (29.4% compared with 13.4%; odds ratio [OR] 2.77, 95% confidence interval [CI] 1.19-6.45) and chronic hypertension (17.1% compared with 3.1%; OR 6.86, 95% CI 2.19-21.51). Antiviral treatment within 2 days of symptom onset decreased the likelihood of ICU admission (31.4% compared with 56.6%, OR 0.36, 95% CI 0.16-0.77).

CONCLUSION

Comorbidities, including chronic hypertension and smoking in pregnancy, increase the likelihood of ICU admission in influenza-like illness hospitalizations, whereas early antiviral treatment may reduce its frequency.

LEVEL OF EVIDENCE

II.