Pandemic influenza and pregnant women

Perception on influenza vaccination in Korean women of childbearing age

Purpose

Women who are pregnant, planning to become pregnant in the influenza season or caring for infant 6-59 months of age are identified as priority groups for influenza vaccination. Vaccination rate is presumed to be low in those women. The purpose of this study was to investigate perceptions of childbearing age women about influenza vaccination.

Materials and Methods

Childbearing age women visiting the department of Obstetrics and Gynecology in 3 University hospitals in Seoul and Gyeonggi-do province were surveyed. Individual interviews were performed to them with questionnaire for 2 months from April to May 2012. Demographic data, Immunization history, general understanding and factors associated with vaccination were asked.

Results

Three hundred fifty-five (71.0%) of total 500 reproductive age women had the experience of influenza vaccination. Among 343 women who has been pregnant at least once, 48 women (16.4%) had vaccination during pregnancy, and 46 of them got vaccination since 2009. One hundred ninety women of total 500 women responded that they would get vaccination if pregnant in the next influenza season (38.0%). In multivariate analysis, statistically significant factors associated with plans of influenza vaccination in pregnancy were as follows: experience of childbirth (odds ratio [OR], 1.97; 95% CI, 1.32 to 2.93), high level of education (OR, 1.96; 95% CI, 1.22 to 3.15), previous influenza vaccination (OR, 1.88; 95% CI, 1.17 to 3.01).

Conclusion

Influenza vaccine coverage on childbearing age women including pregnant women is low because of misperception of vaccination during pregnancy. It is necessary for healthcare provider to correct misunderstanding and to recommend vaccination actively.

A case-control study on risk factors associated with death in pregnant women with severe pandemic H1N1 infection

OBJECTIVES

To describe the risk factors associated with death in pregnant women with severe pandemic H1N1 infection.

DESIGN

Case-control study.

SETTING

Anhui, China.

PARTICIPANTS

A total of 46 pregnant women with severe pandemic H1N1 infection were studied during June 2009-April 2011.

PRIMARY AND SECONDARY OUTCOME MEASURES

All the cases were confirmed by the clinicians and epidemiologists together based on the positive laboratory result.

RESULTS

Of the seven pregnant women who died of the pandemic H1N1 infection, five (70%) cases were in their third trimester. Twenty-nine (63%) cases from the surviving group were admitted to hospital within 3 days after the onset of symptoms, while only one (2%) case from the death group took the earliest admission 2 days after the onset. There was a significant difference on how soon to be admitted between the death and the surviving groups (OR 0.09, 95% CI 0.01 to 0.68). The median time of administrating corticosteroids was 5 days after the onset in the death group and 3 days in the surviving group showing no significant difference between them (p=0.056).

CONCLUSIONS

For the pregnant women with severe p(H1N1) infection, the risk factors associated with death were as follows: the delay of antiviral treatment and being in the third trimester. The corticosteroids therapy appeared to have no effects on preventing the cases from death.

Estrogen mediates innate and adaptive immune alterations to influenza infection in pregnant mice

Pregnancy is a leading risk factor for severe complications during an influenza virus infection. Women infected during their second and third trimesters are at increased risk for severe cardiopulmonary complications, premature delivery, and death. Here, we establish a murine model of aerosolized influenza infection during pregnancy. We find significantly altered innate antiviral responses in pregnant mice, including decreased levels of IFN-β, IL-1α, and IFN-γ at early time points of infection. We also find reduced cytotoxic T cell activity and delayed viral clearance. We further demonstrate that pregnancy levels of the estrogen 17-β-estradiol are able to induce key anti-inflammatory phenotypes in immune responses to the virus independently of other hormones or pregnancy-related stressors. We conclude that elevated estrogen levels result in an attenuated anti-viral immune response, and that pregnancy-associated morbidities occur in the context of this anti-inflammatory phenotype.

Pharmacists' knowledge, attitudes, and practices regarding influenza vaccination and treatment of pregnant women

OBJECTIVES

To understand pharmacists' knowledge, attitudes, and practices regarding vaccination and treatment of pregnant women for seasonal influenza and pandemic 2009 influenza A (H1N1).

DESIGN

Descriptive, exploratory, nonexperimental study.

SETTING

United States between January 21, 2010, and February 9, 2010.

PARTICIPANTS

606 pharmacists who participated in the American Pharmacists Association (APhA) Immunization Certificate Training Program and practice in chain, supermarket, mass merchandise, and independent pharmacies.

INTERVENTION

Electronic survey sent by APhA to 7,356 pharmacists who had participated in its Immunization Certificate Training Program.

MAIN OUTCOME MEASURES

Pharmacists' knowledge, attitudes, and practices regarding vaccination and antiviral treatment of pregnant women for seasonal and H1N1 influenza.

RESULTS

Respondents were more likely to recognize that pregnant women are at an increased risk associated with H1N1 influenza (85%) than to recognize the increased risk associated with seasonal influenza (78%). However, respondents were less likely to believe that they have an important role in vaccinating pregnant women compared with the general public (82% vs. 97%) and less likely to agree that 2009 H1N1 vaccine was safe during pregnancy compared with the seasonal influenza vaccine (78% vs. 87%). Pharmacists who had been vaccinated themselves were more likely to recommend vaccination for pregnant patients. Only 38% believed that antiviral medications such as oseltamivir can be given during pregnancy because the benefits outweigh the risks. However, in response to case studies of pregnant women who were candidates for antiviral medications, respondents indicated that they would take extraordinary steps to ensure that pregnant women were either referred for medical assessment or for assistance in obtaining prescribed antiviral medications.

CONCLUSION

Education efforts that focus on the effectiveness and safety of influenza vaccination during pregnancy and the benefits of treating pregnant women with confirmed or suspected influenza with antiviral medications may be useful in improving pharmacists' support of pharmaceutical interventions to reduce the impact of influenza in pregnant women. Pharmacists' personal decisions regarding vaccination may be a marker for their overall assessment of risks and benefits and may influence their recommendations for pregnant patients.

Influenza Vaccine Coverage among Pregnant Women in a Public Hospital System during the 2009-2010 Pandemic Influenza Season

The purpose of this study was to compare influenza vaccination rates of pregnant women in a public safety-net health system to national coverage rates during the 2009-2010 pandemic influenza season. A chart review of a random sample of deliveries was undertaken to determine rates of coverage and predictors of vaccine coverage of women who obtained prenatal care and delivered in our health system. Rates were calculated from deliveries from when the vaccine was first available through April 30, 2010. Coverage rates were 54% for the seasonal influenza vaccine and 51% for the H1N1 vaccine. Race/ethnicity, insurance status and language spoken did not predict the receipt of either vaccine. When we included only births which occurred through March 12, 2010, as was done in a large population-based study, the rates were 61% and 59%, respectively. Our rates are about 10% higher than the rates reported in that study. Our comprehensive strategy for promoting vaccine coverage achieved higher vaccination rates in a safety-net health system, which serves groups historically less likely to be vaccinated, than those reported for the pregnant population at large.

Clinical characteristics of critical patients with pandemic influenza A (H1N1) virus infection in Chengdu, China

OBJECTIVE

The critical illness of pandemic influenza A (H1N1) virus infection may be associated with relatively poor outcomes. The objective of this study is to describe clinical features and factors associated with the deaths of critical patients.

METHODS

Medical records of 26 critical patients with H1N1 infection admitted from Sept. 1 to Dec. 31, 2009, were retrospectively reviewed. Diagnosis was established by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay.

RESULTS

The mean age of the patients was (40.4 ± 18.4) years and 73.1% of them were male. Clinical manifestations included fever, cough, and sputum production. The laboratory findings included leukocytosis, lymphopenia, C-reaction protein, and lactic dehydrogenase elevation. In this series, 17 subjects survived and 9 died. The parameters between the deaths and survivors were compared, which included acute physiology and chronic health evaluation II (APACHE II) scores (23.8 ± 10.1 vs. 14.3 ± 6.6, P<0.05), sequential organ failure assessment (SOFA) scores (13.3 ± 3.0 vs. 6.6 ± 3.3, P<0.05), and multiple organ dysfunction syndrome (MODS) scores (7.4 ± 2.5 vs. 3.3 ± 1.7, P<0.05). The cases of deaths had higher incidences of cardiovascular failure (100% vs. 41.2%, P<0.05), renal failure (55.6% vs. 11.7%, P<0.05), encephalopathy (44.4% vs. 5.9%, P<0.05), hepatic failure (33.3% vs. 5.9%, P<0.05), and septic shock (33.3% vs. 17.6%, P<0.05).

CONCLUSIONS

The critical patients with H1N1 infection have high APACHE II, SOFA, and MODS scores, which may be associated with an increased risk of death and complex clinical courses.

Score to identify the severity of adult patients with influenza A (H1N1) 2009 virus infection at hospital admission

The objective of this paper was to develop a prognostic index for severe complications among hospitalized patients with influenza A (H1N1) 2009 virus infection. We conducted a prospective observational cohort study of 618 inpatients with 2009 H1N1 virus infection admitted to 36 Spanish hospitals between July 2009 and February 2010. Risk factors evaluated included host-related factors and clinical data at admission. We developed a composite index of severe in-hospital complications (SIHC), which included: mortality, mechanical ventilation, septic shock, acute respiratory distress syndrome, and requirement for resuscitation maneuvers. Six factors were independently associated with SIHC: age >45 years, male sex, number of comorbidities, pneumonia, dyspnea, and confusion. From the β parameter obtained in the multivariate model, a weight was assigned to each factor to compute the individual influenza risk score. The score shows an area under the receiver operating characteristic (ROC) curve of 0.77. The SIHC rate was 1.9 % in the low-risk group, 10.3 % in the intermediate-risk group, and 29.6 % in the high-risk group. The odds ratio for complications was 21.8 for the high-risk group compared with the low-risk group. This easy-to-score influenza A (H1N1) 2009 virus infection risk index accurately stratifies patients hospitalized for H1N1 virus infection into low-, intermediate-, and high-risk groups for SIHC.

Severe 2009 H1N1 infection in early pregnancy

OBJECTIVE

Because pregnancy suppresses the immune system, women at any stage of pregnancy are more susceptible to bacterial and viral infection. Pregnant women might thus be at increased risk of complications from pandemic H1N1 virus infection, and illness may progress rapidly.

CASE REPORT

A 23-year-old primigravida at 9 weeks' gestation was presented to our institution because of the sudden onset of sore throat, fever, chills, and vomiting for 5 days. She was diagnosed with early pregnancy H1N1 infection, vulvar herpes infection, and impending intravascular disseminated coagulopathy. Oseltamivir (Tamiflu) 75 mg and valacyclovir 500 mg were then administered orally twice daily for 5 days. The patient's fever, chills, and vomiting subsided 2 days later. The real-time reverse-transcriptase polymerase chain reaction (RT-PCR) analysis of nasal discharge for influenza virus types A and B showed positive results for the A/H1N1 influenza virus. The early pregnancy was terminated by therapeutic curettage at the patient's request. The surgical specimen revealed products of conception with the presence of necrotic chorionic villi, and focal lymphocytes in decidual tissue. RT-PCR analysis of gestational tissue for A/H1N1 was negative.

CONCLUSION

Pregnant women with H1N1 infection seem to benefit from antiviral therapy.

Review of the pandemic (H1N1) 2009 among pregnant Japanese women

Pregnant women are prone to serious complications when they contract influenza, and a considerable number of pregnant women died from the pandemic (H1N1) 2009 worldwide; however, no maternal mortality occurred in Japan during this pandemic. This review explores the reasons why maternal mortality did not occur in Japan. Two studies conducted during and soon after the pandemic (H1N1) 2009 in Japan suggested the following: 40,000-50,000 pregnant Japanese women took antiviral medicines for prophylaxis after close contact with an infected person; 40% of them (16,000-20,000) contracted the novel influenza and accounted for a half of all 30,000-40,000 pregnant patients with the novel influenza; at least 181 of them required hospitalization; and at least 17 of them developed pneumonitis. Hospitalized women had a 2.5 times higher risk of preterm delivery (at <37 weeks) compared with the general population. The two studies suggested that the following may have contributed to the lack of maternal mortality in Japan: (i) more than 60% of candidates were vaccinated within 1.5 months after the availability of a vaccine against the novel virus; (ii) vaccination reduced the infection rate by 89%; (iii) a large number of women took antiviral drugs before symptom onset after close contact with an infected person; and (iv) approximately 90% of hospitalized pregnant patients took antiviral drugs within 48 hours after symptom onset.

Human teratogens update 2011: can we ensure safety during pregnancy?

Anniversaries of the identification of three human teratogens (i.e., rubella virus in 1941, thalidomide in 1961, and diethylstilbestrol in 1971) occurred in 2011. These experiences highlight the critical role that scientists with an interest in teratology play in the identification of teratogenic exposures as the basis for developing strategies for prevention of those exposures and the adverse outcomes associated with them. However, an equally important responsibility for teratologists is to evaluate whether medications and vaccines are safe for use during pregnancy so informed decisions about disease treatment and prevention during pregnancy can be made. Several recent studies have examined the safety of medications during pregnancy, including antiviral medications used to treat herpes simplex and zoster, proton pump inhibitors used to treat gastroesophageal reflux, and newer-generation antiepileptic medications used to treat seizures and other conditions. Despite the large numbers of pregnant women included in these studies and the relatively reassuring results, the question of whether these medications are teratogens remains. In addition, certain vaccines are recommended during pregnancy to prevent infections in mothers and infants, but clinical trials to test these vaccines typically exclude pregnant women; thus, evaluation of their safety depends on observational studies. For pregnant women to receive optimal care, we need to define the data needed to determine whether a medication or vaccine is "safe" for use during pregnancy. In the absence of adequate, well-controlled data, it will often be necessary to weigh the benefits of medications or vaccines with potential risks to the embryo or fetus.

Clinical features and risk factors for severe and critical pregnant women with 2009 pandemic H1N1 influenza infection in China

BACKGROUND

2009 pandemic H1N1 (pH1N1) influenza posed an increased risk of severe illness among pregnant women. Data on risk factors associated with death of pregnant women and neonates with pH1N1 infections are limited outside of developed countries.

METHODS

Retrospective observational study in 394 severe or critical pregnant women admitted to a hospital with pH1N1 influenza from Sep. 1, 2009 to Dec. 31, 2009. rRT-PCR testing was used to confirm infection. In-hospital mortality was the primary endpoint of this study. Univariable logistic analysis and multivariate logistic regression analysis were used to investigate the potential factors on admission that might be associated with the maternal and neonatal mortality.

RESULTS

394 pregnant women were included, 286 were infected with pH1N1 in the third trimester. 351 had pneumonia, and 77 died. A PaO(2)/FiO(2) ≤ 200 (odds ratio (OR), 27.16; 95% confidence interval (CI), 2.64-279.70) and higher BMI (i.e. ≥ 30) on admission (OR, 1.26; 95% CI, 1.09 to 1.47) were independent risk factors for maternal death. Of 211 deliveries, 146 neonates survived. Premature delivery (OR, 4.17; 95% CI, 1.19-14.56) was associated neonatal mortality. Among 186 patients who received mechanical ventilation, 83 patients were treated with non-invasive ventilation (NIV) and 38 were successful with NIV. The death rate was lower among patients who initially received NIV than those who were initially intubated (24/83, 28.9% vs 43/87, 49.4%; p = 0.006). Septic shock was an independent risk factor for failure of NIV.

CONCLUSIONS

Severe hypoxemia and higher BMI on admission were associated with adverse outcomes for pregnant women. Preterm delivery was a risk factor for neonatal death among pregnant women with pH1N1 influenza infection. NIV may be useful in selected pregnant women without septic shock.

Prenatal care providers and influenza prevention and treatment: lessons from the field

To better understand the knowledge, attitudes, and behaviors of providers regarding influenza infection and vaccination in pregnancy, fourteen focus groups were conducted among 92 providers in Atlanta, GA; Dallas, TX; and Portland, OR in late 2009. NVivo 8.0 was used for analysis. Most providers had no experience with pregnant women severely affected by influenza. Many perceived the 2009 H1N1 pandemic to be limited and mild. Providers knew that pregnant women should receive the 2009 H1N1 vaccine and reported plans to vaccinate more patients than the previous season. Most knew CDC guidelines for antiviral treatment and prophylaxis, but some reported hesitancy with presumptive treatment. Although awareness of influenza's potential to cause severe illness in pregnant women was observed, providers' experience and comfort with influenza prevention and treatment was suboptimal. Sustained efforts to educate prenatal care providers about influenza in pregnancy through trusted channels are critical.

[Recommendations of the Infectious Diseases Work Group (GTEI) of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC) and the Infections in Critically Ill Patients Study Group (GEIPC) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) for the diagnosis and treatment of influenza A/H1N1 in seriously ill adults admitted to the Intensive Care Unit]

The diagnosis of influenza A/H1N1 is mainly clinical, particularly during peak or seasonal flu outbreaks. A diagnostic test should be performed in all patients with fever and flu symptoms that require hospitalization. The respiratory sample (nasal or pharyngeal exudate or deeper sample in intubated patients) should be obtained as soon as possible, with the immediate start of empirical antiviral treatment. Molecular methods based on nucleic acid amplification techniques (RT-PCR) are the gold standard for the diagnosis of influenza A/H1N1. Immunochromatographic methods have low sensitivity; a negative result therefore does not rule out active infection. Classical culture is slow and has low sensitivity. Direct immunofluorescence offers a sensitivity of 90%, but requires a sample of high quality. Indirect methods for detecting antibodies are only of epidemiological interest. Patients with A/H1N1 flu may have relative leukopenia and elevated serum levels of LDH, CPK and CRP, but none of these variables are independently associated to the prognosis. However, plasma LDH> 1500 IU/L, and the presence of thrombocytopenia <150 x 10(9)/L, could define a patient population at risk of suffering serious complications. Antiviral administration (oseltamivir) should start early (<48 h from the onset of symptoms), with a dose of 75 mg every 12h, and with a duration of at least 7 days or until clinical improvement is observed. Early antiviral administration is associated to improved survival in critically ill patients. New antiviral drugs, especially those formulated for intravenous administration, may be the best choice in future epidemics. Patients with a high suspicion of influenza A/H1N1 infection must continue with antiviral treatment, regardless of the negative results of initial tests, unless an alternative diagnosis can be established or clinical criteria suggest a low probability of influenza. In patients with influenza A/H1N1 pneumonia, empirical antibiotic therapy should be provided due to the possibility of bacterial coinfection. A beta-lactam plus a macrolide should be administered as soon as possible. The microbiological findings and clinical or laboratory test variables may decide withdrawal or not of antibiotic treatment. Pneumococcal vaccination is recommended as a preventive measure in the population at risk of suffering severe complications. Although the use of moderate- or low-dose corticosteroids has been proposed for the treatment of influenza A/H1N1 pneumonia, the existing scientific evidence is not sufficient to recommend the use of corticosteroids in these patients. The treatment of acute respiratory distress syndrome in patients with influenza A/H1N1 must be based on the use of a protective ventilatory strategy (tidal volume <10 ml / kg and plateau pressure <35 mmHg) and positive end-expiratory pressure set to high patient lung mechanics, combined with the use of prone ventilation, muscle relaxation and recruitment maneuvers. Noninvasive mechanical ventilation cannot be considered a technique of choice in patients with acute respiratory distress syndrome, though it may be useful in experienced centers and in cases of respiratory failure associated with chronic obstructive pulmonary disease exacerbation or heart failure. Extracorporeal membrane oxygenation is a rescue technique in refractory acute respiratory distress syndrome due to influenza A/H1N1 infection. The scientific evidence is weak, however, and extracorporeal membrane oxygenation is not the technique of choice. Extracorporeal membrane oxygenation will be advisable if all other options have failed to improve oxygenation. The centralization of extracorporeal membrane oxygenation in referral hospitals is recommended. Clinical findings show 50-60% survival rates in patients treated with this technique. Cardiovascular complications of influenza A/H1N1 are common. Such problems may appear due to the deterioration of pre-existing cardiomyopathy, myocarditis, ischemic heart disease and right ventricular dysfunction. Early diagnosis and adequate monitoring allow the start of effective treatment, and in severe cases help decide the use of circulatory support systems. Influenza vaccination is recommended for all patients at risk. This indication in turn could be extended to all subjects over 6 months of age, unless contraindicated. Children should receive two doses (one per month). Immunocompromised patients and the population at risk should receive one dose and another dose annually. The frequency of adverse effects of the vaccine against A/H1N1 flu is similar to that of seasonal flu. Chemoprophylaxis must always be considered a supplement to vaccination, and is indicated in people at high risk of complications, as well in healthcare personnel who have been exposed.

Epidemiological, clinical and laboratory features of patients hospitalized with 2009 pandemic influenza in north of Iran

BACKGROUND

The clinical manifestations and outcome of influenza infection differ between various patients in the world. The purpose of this study was to assess the clinical manifestations of patients with confirmed or suspected novel H1N1 flu infection in Sari, North of Iran.

METHODS

From September 2009 to January 2010, the patients' data were collected by retrospective chart review of medical records. Laboratory confirmation included a positive RT-PCR (reverse transcriptase-polymerase-chain-reaction assay) from a nasal or pharyngeal swab sample.

RESULTS

Nearly 80% of established patients were in age group of 15-45 years. Approximately 14.6% of female cases were pregnant There was no significant difference in clinical and laboratory characteristics of patients with confirmed H1N1 virus infection to total cases with Influenza Like Illness (ILI). Thirty nine (95.1%) of the established patients had a combination of fever plus sore throat or cough. Relative lymphopenia was reported in 36.6%. Pneumonia was the most common complication. Acute pericarditis evolved in one case and aseptic meningitis was reported in another.

CONCLUSION

Precise collecting information of clinical manifestations, risk factors and other characteristics of flu, can help to the early infection detection, timely treatment of patients and proper preventive measurements.

Characterizing the pregnancy immune phenotype: results of the viral immunity and pregnancy (VIP) study

Purpose

The increased risk of morbidity and mortality from certain microbial infections and the demonstrated improvements in the clinical course of some autoimmune diseases support the existence of pregnancy-related alterations in immune status. Elucidating the changes in innate and adaptive immunity during gestation may improve pregnancy outcomes and facilitate the development of targeted therapies for autoimmune diseases.

Method

The Viral Immunity and Pregnancy (VIP) study evaluated over 50 subjects longitudinally at three time points during pregnancy and at two time points post-delivery. Leukocyte enumeration was performed; functional responses of NK cells and CD4 T cells were analyzed, and soluble factors such as cytokines, defensins, and steroid hormones were measured in maternal blood.

Results

In comparison to the post-partum period, the latter part of pregnancy was characterized by significant increases in blood phagocytes and pDCs and decreases in the number and activity of NK and T cells. Alterations were found in antimicrobial proteins and serum cytokines.

Conclusions

These data show that pregnancy is not a period of immunosuppression but an alteration in immune priorities characterized by a strengthening of innate immune barriers and a concomitant reduction in adaptive/inflammatory immunity in the later stages of pregnancy.

Natality decline and miscarriages associated with the 1918 influenza pandemic: the Scandinavian and United States experiences

BACKGROUND

Although pregnancy is a recognized risk factor for severe influenza infection, the effect of influenza on miscarriages and births remains unclear. We examined the relationship between influenza and birth rates during the 1918 pandemic in the United States, Denmark, Sweden, and Norway.

METHODS

We compiled monthly birth rates from 1911 through 1930 in 3 Scandinavian countries and the United States, identified periods of unusually low or high birth rates, and quantified births as "missing" or "in excess" of the normal expectation. Using monthly influenza data, we correlated the timing of peak pandemic exposure and depressions in birth rates, and identified pregnancy stages at risk of influenza-related miscarriage.

RESULTS

Birth rates declined in all study populations in spring 1919 by a mean of 2.2 births per 1000 persons, representing a 5%-15% drop below baseline levels (P < .05). The 1919 natality depression reached its trough 6.1-6.8 months after the autumn pandemic peak, suggesting that missing births were attributable to excess first trimester miscarriages in ∼1 in 10 women who were pregnant during the peak of the pandemic. Pandemic-related mortality was insufficient to explain observed patterns.

CONCLUSIONS

The observed birth depressions were consistent with pandemic influenza causing first trimester miscarriages in ∼1 in 10 pregnant women. Causality is suggested by temporal synchrony across geographical areas.

Complications of the 2009 influenza A/H1N1 pandemic in pregnant women in The Netherlands: a national cohort study

The 2009 influenza A/H1N1 pandemic caused an increase in complications in pregnant women. To be well prepared for a next pandemic, we investigated the obstetric and maternal complications of this pandemic. In our national cohort of 59 pregnant women who were admitted to the hospital, no major complications apart from preterm birth and admission to the neonatal intensive care unit were observed. Although the small size of this study precludes us drawing any definitive conclusions, comparing our results with those in other countries suggests that the influenza A/H1N1 pandemic had a relatively benign course in pregnant women in The Netherlands.

Case-control study of risk factors for hospitalization caused by pandemic (H1N1) 2009

TOC summary: Pregnancy, asthma, diabetes, and a history of smoking were among risk factors found.

We conducted a case–control study to identify risk factors for hospitalization from pandemic (H1N1) 2009 virus infection among persons >16 years of age in Sydney, Australia. The study comprised 302 case-patients and 603 controls. In a logistic regression model, after adjusting for age and sex, risk factors for hospitalization were pregnancy (odds ratio [OR] 22.4, 95% confidence interval [CI] 9.2–54.5), immune suppression (OR 5.5, 95% CI 2.8–10.9), pre-existing lung disease (OR 6.6, 95% CI 3.8–11.6), asthma requiring regular preventive medication (OR 4.3, 95% CI 2.7–6.8), heart disease (OR 2.3, 95% CI 1.2–4.1), diabetes (OR 3.8, 95% CI 2.2–6.5), and current smoker (OR 2.0, 95% CI 1.3–3.2) or previously smoked (OR 2.0, 95% CI 1.3–3.0). Although obesity was not independently associated with hospitalization, it was associated with an increased risk of requiring mechanical ventilation. Public health messages should give greater emphasis on the risk for severe disease among pregnant women and smokers.

Fatal outcome of pandemic H1N1 2009 influenza virus infection is associated with immunopathology and impaired lung repair, not enhanced viral burden, in pregnant mice

Pandemic A (H1N1) 2009 influenza virus (pH1N1) infection in pregnant women can be severe. The mechanisms that affect infection outcome in this population are not well understood. To address this, pregnant and nonpregnant BALB/c mice were inoculated with the wild-type pH1N1 strain A/California/04/09. To determine whether innate immune responses are associated with severe infection, we measured the innate cells trafficking into the lungs of pregnant versus nonpregnant animals. Increased infiltration of pulmonary neutrophils and macrophages strongly correlated with an elevated mortality in pregnant mice. In agreement with this, the product of nitric oxide (nitrite) and several cytokines associated with recruitment and/or function of these cells were increased in the lungs of pregnant animals. Surprisingly, increased mortality in pregnant mice was not associated with higher virus load because equivalent virus titers and immunohistochemical staining were observed in the nasal cavities or lungs of all mice. To determine whether exacerbated inflammatory responses and elevated cellularity resulted in lung injury, epithelial regeneration was measured. The lungs of pregnant mice exhibited reduced epithelial regeneration, suggesting impaired lung repair. Despite these immunologic alterations, pregnant animals demonstrated equivalent percentages of pulmonary influenza virus-specific CD8(+) T lymphocytes, although they displayed elevated levels of T-regulator lymphocytes (Tregs) in the lung. Also, pregnant mice mounted equal antibody titers in response to virus or immunization with a monovalent inactivated pH1N1 A/California/07/09 vaccine. Therefore, immunopathology likely caused by elevated cellular recruitment is an implicated mechanism of severe pH1N1 infection in pregnant mice.

Infectious respiratory disease outbreaks and pregnancy: occupational health and safety concerns of Canadian nurses

INTRODUCTION

This paper is a report of a qualitative study of emergency and critical care nurses' perceptions of occupational response and preparedness during infectious respiratory disease outbreaks including severe acute respiratory syndrome (SARS) and influenza.

PROBLEM

Healthcare workers, predominantly female, face occupational and personal challenges in their roles as first responders/first receivers. Exposure to SARS or other respiratory pathogens during pregnancy represents additional occupational risk for healthcare workers.

METHODS

Perceptions of occupational reproductive risk during response to infectious respiratory disease outbreaks were assessed qualitatively by five focus groups comprised of 100 Canadian nurses conducted between 2005 and 2006.

RESULTS

Occupational health and safety issues anticipated by Canadian nurses for future infectious respiratory disease outbreaks were grouped into four major themes: (1) apprehension about occupational risks to pregnant nurses; (2) unknown pregnancy risks of anti-infective therapy/prophylaxis; (3) occupational risk communication for pregnant nurses; and (4) human resource strategies required for pregnant nurses during outbreaks. The reproductive risk perceptions voiced by Canadian nurses generally were consistent with reported case reports of pregnant women infected with SARS or emerging influenza strains. Nurses' fears of fertility risks posed by exposure to infectious agents or anti-infective therapy and prophylaxis are not well supported by the literature, with the former not biologically plausible and the latter lacking sufficient data.

CONCLUSIONS

Reproductive risk assessments should be performed for each infectious respiratory disease outbreak to provide female healthcare workers and in particular pregnant women with guidelines regarding infection control and use of anti-infective therapy and prophylaxis.

Immunogenicity of an inactivated monovalent 2009 H1N1 influenza vaccine in pregnant women

BACKGROUND

Although pregnant women are at increased risk of severe illness following influenza infection, there is relatively little information on the immunogenicity of influenza vaccines administered during pregnancy.

METHODS

We conducted a clinical trial that enrolled 120 pregnant women in which participants were randomly assigned to receive an inactivated 2009 H1N1 influenza vaccine containing either 25 μg or 49 μg of hemagglutinin (HA) in a 2-dose series with a 21-day period between administration of the first and second doses.

RESULTS

Following the first vaccination, HA inhibition (HAI) titers of ≥1:40 were detected in 93% (95% confidence interval [CI], 82%-98%) of subjects who received the 25-μg dose and 97% (95% CI, 88%-100%) of subjects receiving the 49-μg dose. In cord blood samples, HAI titers of ≥1:40 were found in 87% (95% CI, 73%-96%) of samples from the 25-μg dose group and in 89% (95% CI, 76%-96%) from the 49-μg dose group. Microneutralization titers tended to be higher than HAI titers, but the patterns of response were similar.

CONCLUSIONS

In pregnant women, 1 dose of an inactivated 2009 H1N1 influenza vaccine containing 25 μg of HA elicited an antibody response typically associated with protection against influenza infection. Efficient transplacental transfer of antibody was also documented.

Severe 2009 A/H1N1v influenza in pregnant women in Spain

OBJECTIVES

To describe the severity of the 2009 influenza A/H1N1v illness among pregnant women admitted to Spanish intensive care units.

DESIGN AND PATIENTS

Prospective, observational, multicenter study conducted in 148 Spanish intensive care units. We reviewed demographic and clinical data from the Spanish Society of Intensive Care Medicine database reported from April 23, 2009, to February 15, 2010. We included women of reproductive age (15-44 yrs) with confirmed A/H1N1v infection admitted to intensive care units.

MAIN RESULTS

Two hundred thirty-four women of reproductive age were admitted to intensive care units, 50 (21.4%) of them pregnant. Seven deaths were recorded in pregnant and 22 in nonpregnant women. Among intensive care unit admissions, there were no statistically significant differences between pregnant women and nonpregnant in Acute Physiology and Chronic Health Evaluation II, Sequential Organ Failure Assessment scores, chest x-rays, inotrope requirement, or need for mechanical ventilation or steroid therapy. Mortality risk was significantly associated with Acute Physiology and Chronic Health Evaluation II, Sequential Organ Failure Assessment, and obesity. Viral pneumonia was more frequent in pregnant women than in nonpregnant women, with an odds ratio (adjusted for asthma, time from onset influenza symptoms to hospital admission and obesity) of 4.9 (95% confidence interval: 1.4-17.2). The development of primary viral pneumonia in women of reproductive age appeared to be related to the time of commencement of antiviral treatment, the lowest rates being reported with initiation of antiviral therapy within 48 hrs of symptom onset (63.6% vs. 82.6%, p = .03). However, antiviral therapy was started within this time span in only 14% of pregnant women.

CONCLUSIONS

More than 20% of women of reproductive age admitted to intensive care unit for pH1N1 infection were pregnant. Pregnancy was significantly associated with primary viral pneumonia. Pregnant women should receive prompt treatment with oseltamivir within 48 hrs of the onset of influenza symptoms.

The effect of influenza virus A on th1/th2 balance and alveolar fluid clearance in pregnant rats

ABSTRACT Pregnant women are more prone to H1N1 infection and often with severe complications. The authors studied the influence of H1N1 infection on T-helper cell type 1/type 2 (Th1/Th2) balance and alveolar fluid clearance (AFC) in pregnant rats. The pregnant rats were infected intranasally with influenza virus. Peripheral blood interferon-γ (IFN-γ) and interleukin-4 (IL-4) were measured by enzyme-linked immunosorbent assay (ELISA) and AFC was estimated by albumin concentration in alveolar lavage. The ratio of IFN-γ/IL-4 in nonpregnant rats was 21 ± 7. There was significant increase in both cytokines in infected pregnant rats compared with noninfected counterparts, with dramatic reduction in IFN-γ/IL-4 ratio (8 ± 3) compared to that (15 ± 8) in normal pregnant group. AFC of normal nonpregnant rats was 17% ± 3% and H1N1 infection reduced it to 11% ± 2%. AFC of normal pregnant rats was 22% ± 2% and H1N1 infection reduced it to 10% ± 2%. Dexamethasone reversed AFC in both nonpregnant and pregnant groups (14% ± 4% and 13% ± 2%, respectively). These results show that influenza virus A infection leads to Th2-biased immunity and reduces AFC in normal rats, and further worsens these in pregnant rats. Dexamethasone reverses these effects in both pregnant and nonpregnant rats.

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

To summarize the literature regarding 2009 H1N1 influenza A during pregnancy, we conducted a systematic literature review using a PubMed search and other strategies. Studies were included if they reported 2009 H1N1 influenza in pregnant women as original data. In all, 2153 abstracts were reviewed, and a total of 120 studies were included. Data were extracted regarding number of cases, additional risk factors for influenza-associated complications, treatment, and maternal and pregnancy outcomes. Authors were contacted to determine the extent of overlap when it was suspected. Pregnancy was associated with increased risk of hospital and intensive care unit admission and of death. Pregnant women who received delayed treatment with neuraminidase inhibitors or who had additional risk factors were more likely to develop severe disease. Preterm and emergency cesarean deliveries were frequently reported. These results reinforce the importance of early identification and treatment of suspected influenza in this high-risk population.

[Timely registration of fatalities in the state of Hessen. Experiences during the influenza A/H1N1 pandemic]

Timely registration of fatalities is important for the assessment of course, extent, risk of age groups, and magnitude or severity of health threats. Nevertheless, timely data of casualties are not available on the state or national level. The current paper describes the implementation and structure of a surveillance system for the timely registration of casualties in the state of Hesse (Germany) and the experience obtained during the pandemic 2009/10. The delay of the case-based registration appears tolerable and after 2 weeks more than 80% of all deaths for a given week are registered. In 2008, the forwarding of the electronically registered data from the registry offices (95% of all cases) to the state statistical office (HSL) had been accelerated from a monthly to a weekly base. The HSL provides--on a weekly basis--this case-based data in accordance with data protection rules to the Hesse State Health Office (HLPUG, "Hessischer Landesprüfungs- und Untersuchungsamt im Gesundheitswesen"). During the pandemic, the data allowed assessment of the excess mortality with a delay of 2 weeks. No significant excess mortality was apparent; however, a slight increase was observed in the age groups 15-34, 35-49, and 50-59. Correlation of time with the severity of the A/H1N1v epidemic was not very strong. Hence, the data did not indicate an excess significantly exceeding the number of death cases registered with the mandatory reporting system of 21 cases for Hesse.

Determinants of non-vaccination against pandemic 2009 H1N1 influenza in pregnant women: a prospective cohort study

Background

In October 2009, the French government organized a national-wide, free of charge vaccination campaign against pandemic H1N1 influenza virus, especially targeting pregnant women, a high risk group for severe illness. The study objective was to evaluate pandemic flu vaccine uptake and factors associated with non-vaccination in a population of pregnant women.

Methodology/Principal Findings

In a prospective cohort conducted in 3 maternity hospitals in Paris, 882 pregnant women were randomly included between October 12, 2009 and February 3, 2010, with the aim to study characteristics of pandemic influenza during pregnancy. At inclusion, socio-demographic, medical, obstetrical factors and those associated with a higher risk of flu exposition and disease-spreading were systematically collected. Pandemic flu vaccine uptake was checked until delivery. 555 (62.9%) women did not get vaccinated. Determinants associated with non-vaccination in a multivariate logistic regression were: geographic origin (Sub-Saharan African origin, adjusted Odd Ratio aOR = 5.4[2.3–12.7], North African origin, aOR = 2.5[1.3–4.7] and Asian origin, aOR = 2.1[1.7–2.6] compared to French and European origin) and socio-professional categories (farmers, craftsmen and tradesmen, aOR = 2.3[2.0–2.6], intermediate professionals, aOR = 1.3[1.0–1.6], employees and manual workers, aOR = 2.5[1.4–4.4] compared to managers and intellectual professionals). The probability of not receiving pandemic flu vaccine was lower among women vaccinated against seasonal flu in the previous 5 years (aOR = 0.6[0.4–0.8]) and among those who stopped smoking before or early during pregnancy (aOR = 0.6[0.4–0.8]). Number of children less than 18 years old living at home, work in contact with children or in healthcare area, or professional contact with the public, were not associated with a higher vaccine uptake.

Conclusions/Significance

In this cohort of pregnant women, vaccine coverage against pandemic 2009 A/H1N1 flu was low, particularly in immigrant women and those having a low socio-economic status. To improve its effectiveness, future vaccination campaign for pregnant women should be more specifically tailored for these populations.

Clinical characteristics of pregnant women with influenza-like illness during the 2009 H1N1 pandemic and use of a standardized management algorithm

We sought to describe the clinical characteristics of pregnant women with influenza-like illness during the 2009 H1N1 pandemic with the use of a standardized management algorithm. From June 2009 through March 2010, we assembled a prospective cohort of pregnant women with influenza-like illness at a single tertiary care center using a standardized algorithm. Clinical outcomes were compared between women with 2009 H1N1 virus and those without. In all, 45 women were included. Seventeen had 2009 H1N1 infection and 28 did not. Demographic characteristics were similar between groups. The median temperature upon presentation (99.7 vs 98.8°F, P = .004) was slightly higher among those with 2009 H1N1. All those with 2009 H1N1 influenza and 89% of those without were treated with oseltamivir. A total of 12 women (27%) were hospitalized. There were no endotracheal intubations or deaths. Among this cohort of pregnant women, most were treated as outpatients and had favorable maternal outcomes.

Pandemic 2009 influenza A (H1N1) in 71 critically ill pregnant women in California

We sought to describe the characteristics and clinical management of 71 critically ill pregnant women with pandemic 2009 influenza A (H1N1 [2009 H1N1]). This was a retrospective case series from April 23, 2009, through March 18, 2010, of pregnant women with 2009 H1N1 in intensive care units in California. Among 71 critically ill pregnant women with 2009 H1N1, rapid decline in clinical status was noted with a median duration of 1 day from hospital admission to intensive care unit admission. Adverse events were common, and included sepsis (n = 26), hematologic disorder (n = 17), and pneumothorax (n = 15). Of 42 women requiring invasive ventilation, 15 (36%) died. In total, 23 women required rescue therapies for severe gas exchange abnormalities. Adverse events were significantly associated with survival (P = .0003). Women who received early antiviral treatment were significantly more likely to survive (relative risk, 1.43; 95% confidence interval, 1.18-1.75). Critically ill pregnant women with 2009 H1N1 declined rapidly and developed frequent adverse events including death.

The Pregnancy and Influenza Project: design of an observational case-cohort study to evaluate influenza burden and vaccine effectiveness among pregnant women and their infants

The US Centers for Disease Control and Prevention is conducting an observational study of 300-500 women infected with influenza during pregnancy. Women are being recruited from members of the Kaiser Permanente health plan in 2 metropolitan areas before and during the 2010 through 2011 influenza season either following routine prenatal care visits or presentation with an acute respiratory infection. All enrolled mothers and their infants will be followed up through 1 month after delivery. Infants of mothers who had influenza during pregnancy and 1000 infants of mothers who were not diagnosed with influenza during pregnancy will be followed up for an additional 5 months. The Pregnancy and Influenza Project is focused on better understanding the burden of influenza during and after pregnancy and estimating the effectiveness of maternal influenza vaccination against influenza among women and their infants confirmed by real-time reverse transcription polymerase chain reaction assays.

Influenza vaccination coverage among pregnant women--National 2009 H1N1 Flu Survey (NHFS)

We sought to describe vaccination with influenza A (H1N1) 2009 monovalent (2009 H1N1) and trivalent seasonal (seasonal) vaccines among pregnant women during the 2009 through 2010 influenza season. A national H1N1 flu survey was conducted April through June 2010. The 2009 H1N1 and seasonal vaccination coverage estimates were 45.7% and 32.1%, respectively, among pregnant women aged 18-49 years. Receipt of a health care provider's recommendation for vaccination, perceived effectiveness of influenza vaccinations, and perceived high chance of influenza infection were independently associated with higher 2009 H1N1 and seasonal vaccination coverage. Pregnancy during October 2009 through January 2010 was independently associated with higher 2009 H1N1 vaccination coverage. The 2009 H1N1 vaccination level among pregnant women was higher than the seasonal vaccination level during the 2009 through 2010 season; it was also higher than vaccination among nonpregnant women with and without high-risk conditions. Health care providers and public health messaging played important roles in influencing vaccination behavior.

Preparing for influenza after 2009 H1N1: special considerations for pregnant women and newborns

Pregnant women and their newborn infants are at increased risk for influenza-associated complications, based on data from seasonal influenza and influenza pandemics. The Centers for Disease Control and Prevention (CDC) developed public health recommendations for these populations in response to the 2009 H1N1 pandemic. A review of these recommendations and information that was collected during the pandemic is needed to prepare for future influenza seasons and pandemics. The CDC convened a meeting entitled "Pandemic Influenza Revisited: Special Considerations for Pregnant Women and Newborns" on August 12-13, 2010, to gain input from experts and key partners on 4 main topics: antiviral prophylaxis and therapy, vaccine use, intrapartum/newborn (including infection control) issues, and nonpharmaceutical interventions and health care planning. Challenges to communicating recommendations regarding influenza to pregnant women and their health care providers were also discussed. After careful consideration of the available information and individual expert input, the CDC updated its recommendations for these populations for future influenza seasons and pandemics.

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

We sought to describe characteristics of hospitalized reproductive-aged (15-44 years) women with seasonal (2005/2006 through 2008/2009) and 2009 pandemic influenza A (H1N1) virus infection. We used population-based data from the Emerging Infections Program in 10 US states, and compared characteristics of pregnant (n = 150) and nonpregnant (n = 489) seasonal, and pregnant (n = 489) and nonpregnant (n = 1088) pandemic influenza cases using χ(2) and Fisher's exact tests. Pregnant women represented 23.5% and 31.0% of all reproductive-aged women hospitalized for seasonal and pandemic influenza, respectively. Significantly more nonpregnant than pregnant women with seasonal (71.2% vs 36.0%) and pandemic (69.7% vs 31.9%) influenza had an underlying medical condition other than pregnancy. Antiviral treatment was significantly more common with pandemic than seasonal influenza for both pregnant (86.5% vs 24.0%) and nonpregnant (82.0% vs 55.2%) women. Pregnant women comprised a significant proportion of influenza-hospitalized reproductive-aged women, underscoring the importance of influenza vaccination during pregnancy.

Pharmacokinetics of oseltamivir among pregnant and nonpregnant women

We sought to delineate the pharmacokinetics (PK) of oseltamivir and its active metabolite oseltamivir carboxylate during pregnancy. Physiologic changes of pregnancy, including increased renal filtration and secretion, may increase the clearance of oseltamivir carboxylate. Sixteen pregnant women taking oseltamivir for prophylaxis or treatment of suspected/proven influenza infection were enrolled. Twenty-three nonpregnant reproductive-age females served as the control group. The primary PK endpoint was area under the plasma concentration time curve for oseltamivir carboxylate. Pregnancy did not alter the PK parameters of the parent compound, oseltamivir. However, for oseltamivir carboxylate the area under the plasma concentration time curve was significantly lower (P = .007) and the apparent clearance significantly higher (P = .006) in pregnant women compared with nonpregnant women. Pregnancy produces lower systemic levels of oseltamivir carboxylate. Increasing the dose and/or dosing frequency of oseltamivir during pregnancy may be necessary to achieve comparable exposure in pregnant and nonpregnant women.

Maternal deaths associated with H1N1 influenza virus infection in Turkey: a whole-of-population report

OBJECTIVE

To review the clinical and demographic characteristics of pregnant and postpartum women who died as a consequence of influenza A H1N1 (2009) infection in Turkey.

DESIGN

A review of the records for pregnant and postpartum women who died as a consequence of H1N1 influenza virus infection.

SETTING

Nationwide in Turkey.

POPULATION

Thirty-six pregnant or postpartum women who died as a result of confirmed pandemic H1N1 influenza virus infection.

METHODS

Using the General Directorate of Mother and Child Health and Family Planning (MCHFP) Registry of the Ministry of Health of Turkey, we identified all pregnant and postpartum women who died as a result of confirmed influenza A H1N1 (2009) infection between 29 October and 31 December 2009.

MAIN OUTCOME MEASURE

Maternal mortality as a result of H1N1 virus infection.

RESULTS

The average time from symptom onset to initial presentation for health care was approximately 2.5 days, and the mean time from symptom onset to the receipt of antiviral medication was approximately 5.5 days. Only one-fifth of all women received early antiviral treatment (administered 2 days or less after symptom onset) and only one woman was vaccinated for H1N1 influenza 1 week before the onset of symptoms. The cause-specific maternal mortality ratio for H1N1 influenza infection in Turkey was estimated to be 3.01. The calculated risk of death associated with H1N1 influenza virus infection was approximately four times higher in pregnant and postpartum women than in the general population (relative risk, 3.88; 95% confidence interval, 2.77-5.43).

CONCLUSIONS

Pregnant women are at increased risk for complications of, and death from, H1N1 influenza infection. Prompt evaluation and antiviral treatment of influenza-like illness should be considered in such women. Vaccination for H1N1 influenza may reduce the total number of deaths in pregnant and postpartum women. The high cause-specific maternal mortality rate suggests that H1N1 influenza virus infection may have increased the 2009 maternal mortality ratio in Turkey.

Pregnancy and safety outcomes in women vaccinated with an AS03-adjuvanted split virion H1N1 (2009) pandemic influenza vaccine during pregnancy: a prospective cohort study

Infection with influenza virus during pregnancy poses a significant risk of complications for both mother and fetus. During the H1N1 2009 pandemic, pregnant women constituted one of the priority groups for vaccination in many countries, creating a need for close monitoring of the safety of the vaccine in pregnant women. We present findings from an analysis of a cohort of pregnant women (N=267) from a prospective, observational, post-authorization safety study of the AS03-adjuvanted split virion H1N1 (2009) pandemic vaccine. There were 265 known pregnancy outcomes with 261 live births, four spontaneous abortions with no congenital anomalies, and no stillbirths. There were six live births with congenital anomalies, of which one was diagnosed before vaccination. A total of 247 women (94.6%), of whom four had twin pregnancies, delivered at term, and 14 women (5.4%), of whom two had twin pregnancies, delivered preterm (between Weeks 24 and 36 of gestation), with three of them (1.1%) occurring before 32 weeks (very preterm). Twenty-one neonates (8.1%) had a low birth weight (<2.5 kg), of whom nine (3.5%) were term neonates. The prevalence of all outcomes was in line with the expected rates. The adverse events reported were consistent with the events anticipated to be reported by this study population. No adverse events of special interest were reported. The results of this analysis suggest that exposure to the AS03 adjuvanted H1N1 (2009) vaccine during pregnancy does not increase the risk of adverse pregnancy outcomes including spontaneous abortion, congenital anomalies, preterm delivery, low birth weight neonates, or maternal complications. Although limited in size, the fully prospective nature of the safety follow-up of these women vaccinated during pregnancy is unique and offers an important degree of reassurance for the use of the AS03 adjuvanted H1N1 (2009) vaccine in this high risk group for H1N1 infection.

Safety of oseltamivir in pregnancy: a review of preclinical and clinical data

Pregnant women with influenza are at increased risk of morbidity, particularly due to respiratory complications. A high excess mortality rate among pregnant women has been observed in previous influenza pandemics and healthcare agencies have provided recommendations on the use of oseltamivir to treat pregnant women who are infected with the pandemic (H1N1) 2009 virus. This article reviews pre-clinical and clinical data to assess the safety of oseltamivir administered during pregnancy, in the context of the effects of influenza on adverse pregnancy outcomes and fetal malformations. The effects of influenza during pregnancy, whether mediated directly by the virus or by fever or other events secondary to the underlying infection, are not yet well understood, but some data indicate an increased risk of birth defects in women infected with influenza during the first trimester. Animal and toxicology studies do not suggest that clinically effective dosages of oseltamivir have the potential to produce adverse effects on fetal development. Additionally, transplacental transfer of the drug and its active metabolite was very limited and not detectable at normal therapeutic doses in an ex vivo human placenta model. To investigate the safety of oseltamivir in pregnancy, the Roche oseltamivir safety database was searched for all exposures to oseltamivir during pregnancy in the 9 years up to 14 December 2008. In addition, a search of the literature was carried out. Of 232 maternal exposures to oseltamivir in the Roche database, pregnancy outcomes were known for 115 of these exposures. The incidence of adverse pregnancy outcomes was as follows: spontaneous abortions 6.1% (7/115), therapeutic abortions 11.3% (13/115) and pre-term deliveries 2.1% (2/94 live births), values that are not higher than background incidence rates. Fetal outcomes were known in 100 of the 232 exposures. For the nine cases of birth defect that were reported, the timing of oseltamivir exposure in relation to the sensitive period for inducing the birth defect was analysed. Two cases of ventricular septal defect, a more common birth defect, and one case of anophthalmos, an uncommon birth defect, were consistent with exposure to oseltamivir during the sensitive period for these birth defects. For other birth defects, there was either no exposure to oseltamivir during the sensitive period for the defect or insufficient information for assessment. These findings were consistent with other reports in the published literature, including a series of 79 Japanese women exposed to oseltamivir during the first trimester. Together with the other evidence reviewed herein, review of the company safety database suggests that oseltamivir is unlikely to cause adverse pregnancy or fetal outcomes, but available data are limited. Clinicians who use oseltamivir in pregnant women should consider the available safety information, the pathogenicity of the circulating influenza virus strain, the woman's general health and the guidance provided by health authorities. Roche will continue to monitor all reports of oseltamivir use during pregnancy.

Seroprevalence of pandemic (H1N1) 2009 in pregnant women in China: an observational study

Background

We investigated the seropositive rates and persistence of antibody against pandemic (H1N1) 2009 virus (pH1N1) in pregnant women and voluntary blood donors after the second wave of the pandemic in Nanjing, China.

Methodology/Principal Findings

Serum samples of unvaccinated pregnant women (n = 720) and voluntary blood donors (n = 320) were collected after the second wave of 2009 pandemic in Nanjing. All samples were tested against pH1N1 strain (A/California/7/2009) with hemagglutination inhibition assay. A significant decline in seropositive rates, from above 50% to about 20%, was observed in pregnant women and voluntary blood donors fifteen weeks after the second wave of the pandemic. A quarter of the samples were tested against a seasonal H1N1 strain (A/Brisbane/59/2007). The antibody titers against pH1N1 strain were found to correlate positively with those against seasonal H1N1 strain. The correlation was modest but statistically significant.

Conclusions and Significance

The high seropositive rates in both pregnant women and voluntary blood donors suggested that the pH1N1 virus had widely spread in these two populations. Immunity derived from natural infection seemed not to be persistent well.

2009 pandemic influenza A (H1N1) and vaccine failure in pregnancy

BACKGROUND

Emerging data suggest that pregnancy conveys high risk for severe complications from the 2009 pandemic influenza A virus (2009 H1N1) infection.

CASE

We describe an infected pregnant woman with critical illness owing to acute respiratory distress syndrome despite previous vaccination. Early serologic testing indicated absent immunity, followed 11 days later by a robust immune response. The patient required mechanical ventilation for 11 days, but ultimately improved, and was discharged home on hospital day 14.

CONCLUSION

With the expectation that 2009 H1N1 will continue to cause disease in the immediate future, the virus has been included as a component of the 2010-2011 seasonal influenza vaccine. Vaccination of pregnant women is strongly encouraged. However, regardless of vaccination history, clinicians should remain vigilant for 2009 H1N1 infection when the virus is in circulation, and should not delay antiviral treatment of pregnant women with suspected influenza.

Adverse events in pregnant women following administration of trivalent inactivated influenza vaccine and live attenuated influenza vaccine in the Vaccine Adverse Event Reporting System, 1990-2009

OBJECTIVE

The objective of the study was to characterize reports to the Vaccine Adverse Event Reporting System (VAERS) in pregnant women who received seasonal influenza vaccines to assess for potential vaccine safety concerns.

STUDY DESIGN

We searched VAERS for reports of adverse events (AEs) in pregnant women who received trivalent inactivated influenza vaccine (TIV) from July 1, 1990 through June 30, 2009, or live attenuated influenza vaccine (LAIV) from July 1, 2003, through June 30, 2009.

RESULTS

A total of 148 reports after TIV and 27 reports after LAIV were identified. Twenty TIV (13.5%) and 1 LAIV (4%) reports were classified as serious. No specific AEs were reported in 30 TIV (20.3%) and 16 LAIV (59%) reports. The most common pregnancy-specific AE was spontaneous abortion: 17 after TIV (11.5%) and 3 after LAIV (11%). The reporting rate of spontaneous abortion was 1.9 per million pregnant women vaccinated.

CONCLUSION

No unusual patterns of pregnancy complications or fetal outcomes were observed in the VAERS reports of pregnant women after the administration of TIV or LAIV.

2009 pandemic influenza A (H1N1) virus infection in postpartum women in California

OBJECTIVE

The objective of the study was to characterize severe illness because of the 2009 pandemic influenza A (H1N1) infection in postpartum women.

STUDY DESIGN

We reviewed case reports of infected hospitalized postpartum (≤ 6 months from delivery) women identified through statewide surveillance in California. From April 23 through August 11, 2009, all hospitalizations and/or deaths were reported. After August 11, reporting was limited to cases requiring intensive care or deaths.

RESULTS

From April 23 to December 31, 2009, 15 cases were reported; 11 (73%) had symptom onset within 7 days postpartum. Of 10 hospitalized cases reported through August 11, 4 required intensive care, 3 required mechanical ventilation, and 2 died. Of 5 cases requiring intensive care reported after August 11, all required mechanical ventilation and 1 died. Overall, 6 (43%) received antivirals within 48 hours of symptom onset.

CONCLUSION

The 2009 H1N1 can cause severe illness in postpartum women, especially in the first week following delivery.