Maternal influenza during pregnancy and risk of congenital abnormalities in offspring

BACKGROUND: The teratogenic effect of influenza viruses is currently being debated, and we examined the large population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities (HCCSCA) to study the possible association between maternal influenza and various congenital abnormalities (CAs). METHODS: The 1980-1996 HCCSCA includes 22,843 newborns or fetuses with CAs, and 38,151 matched controls (newborn infants without any abnormalities). RESULTS: In the case group, 1328 (5.8%) mothers had influenza at some time during their pregnancies compared to 1838 (4.8%) mothers in the control group (adjusted prevalence odds ratios [PORs], 1.3; 95% confidence interval [CI], 1.2-1.4). In the calculation of the adjusted PORs, the use of antifever drugs and maternal employment status were considered. When cases and their matched controls were compared, there was a higher prevalence of maternal influenza during the second and/or third month of pregnancy for the group of newborns with cleft lip +/- palate (adjusted POR, 3.2; 95% CI, 2.0-5.3), neural-tube defects (adjusted POR, 1.9; 95% CI, 1.1-3.3), and cardiovascular malformations (adjusted POR, 1.7; 95% CI, 1.3-2.3). However, a direct teratogenic effect from influenza viruses appears to be unlikely, and we suggest that the higher prevalence of the CAs indicated above can be explained mainly by fever, because this risk was reduced by the use of antifever drugs. Periconceptional folic acid supplementation also showed some preventive effect for these CAs. CONCLUSIONS: The indirect teratogenic effect of maternal influenza during pregnancy may be restricted by appropriate medical treatment (e.g., antifever drugs) and periconceptional folic acid supplementation.     

Maternal severe migraine and risk of congenital limb deficiencies

BACKGROUND: Migraines occurs frequently during pregnancy; however, there are no published data on their possible teratogenic potential in a controlled epidemiological study. Therefore, we examined the risk of congenital abnormalities in infants born to women who had migraines and other headaches during pregnancy. METHODS: Between 1980 and 1996, the Hungarian Case-Control Surveillance of Congenital Abnormalities evaluated 22,843 cases (newborns or fetuses) with congenital abnormalities, 38,151 control newborn infants without any abnormalities, and 834 malformed controls with Down syndrome. RESULTS: Migraines anytime during pregnancy occurred in 565 (2.5%) mothers of the case group compared with 713 (1.9%) mothers in the control group (crude prevalence odds ratio [POR], 1.3; 95% confidence interval [CI], 1.2-1.5) and 24 (2.9%) pregnant women in the malformed control group (crude POR, 0.9; 95% CI, 0.6-1.3) The mothers of 247 cases, 533 controls, and 21 malformed controls had severe migraines during the second and/or third months of pregnancy. There was only 1 congenital abnormality group: limb deficiencies, which had a higher rate of maternal migraines during the second and third months of pregnancy both at the comparison of cases and matched controls (adjusted POR, 2.5; 95% CI, 1.1-5.8) and of cases and malformed controls (adjusted POR, 1.7; 95% CI, 1.3-3.0). There was no association between other headaches and different congenital abnormalities at the comparison of cases and controls. CONCLUSIONS: Our data showed that maternal severe migraines during the second and/or third months of pregnancy were associated with an increased risk of congenital limb deficiencies. A similar association was not detected between congenital anomalies and other headaches during pregnancy. Our study was not based on a prior hypothesis; therefore, these data can be considered only as a signal that needs confirmation by independent data sets.     

Maternal panic disorder and congenital abnormalities: a population-based case-control study

BACKGROUND: Maternal panic disorder in pregnancy is the most common manifestation of anxiety disorders in Hungary. The association between panic disorder during pregnancy and structural birth defects, i.e., congenital abnormalities, was studied. METHODS: The prevalence of maternal panic disorder in cases with different congenital abnormalities was compared to that of matched controls in the population-based Hungarian Case-Control Surveillance System of Congenital Abnormalities. RESULTS: Of 22,843 cases with congenital abnormalities, 210 (0.9%) had mothers with panic disorder during pregnancy compared to 187 (0.5%) of 38,151 controls (adjusted prevalence odds ratio [POR] 1.6; 95% CI, 1.3-2.0). Specific groups of congenital abnormalities were also assessed versus controls. Cases with isolated cleft lip with or without cleft palate (CL/P) (adjusted POR, 3.4; 95% CI, 1.3-9.0) and multiple congenital abnormalities (adjusted POR, 3.0; 95% CI, 1.2-7.2) were more likely to have had mothers with panic disorder during the study pregnancy. Notably, among mothers with panic disorders, the associations were found only in offspring of untreated mothers. CONCLUSIONS: A higher rate of isolated CL/P and multiple congenital abnormalities may be caused by the direct biological effect of panic disorder or by the interaction of maternal panic disorder and lifestyle factors. Antipanic drug treatment seems to have a protective effect for isolated CL/P and multiple congenital abnormalities. Birth Defects Research (Part A), 2006.     

Congenital heart disease in the offspring and maternal habits and home exposures during pregnancy.

To test the effect of maternal habits and home exposures during early pregnancy on the occurrence of congenital heart disease in the offspring, 406 cases and 756 controls were studied. The cases included all cardiovascular malformations detected in Finland during 1982-1983, while the healthy controls were randomly selected from all babies born during the same period. Case and control mothers were interviewed after delivery using a structured and pre-tested questionnaire. Maternal overall drug consumption during the first trimester was as prevalent among case mothers (13.3%) as controls (14.6%). Neither was the risk of congenital heart disease associated with maternal use of contraceptive pills, salicylates, diazepam, or sweetening agents separately. Maternal exposures to disinfectants, dyes, lacquers, paints, pesticides, or glues at home were equally prevalent in case and control groups. Several earlier miscarriages was a predictor of an infant born with congenital heart disease (OR = 2.7, CI95 = 1.4-5.3). Maternal ultrasound examination was performed during the first 16 weeks of pregnancy more often among the case group (28.3%) than among the control group (22.0%). However, the association between ultrasound examination and the risk of congenital heart disease in the offspring was not statistically significant (OR = 1.2, 95% confidence interval 0.9-1.7) when adjusted for confounding factors such as the threat of miscarriage in logistic regression analysis. It is concluded that maternal ultrasound examination, intake of some common drugs, and exposure to a number of environmental factors at home during early pregnancy are probably not harmful for the developing fetal heart.     

Maternal Obesity and Infant Heart Defects

Objective: This study determined whether obese women have an increased risk of cardiovascular defects in their offspring compared with average weight women. Research Methods and Procedures: In a case‐control study, prospectively collected information was obtained from Swedish medical health registers. The study included 6801 women who had infants with a cardiovascular defect and, as controls, all delivered women (N = 812, 457) during the study period (1992 to 2001). Infants with chromosomal anomalies or whose mothers had pre‐existing diabetes were excluded. Obesity was defined as BMI >29 kg/m², and morbid obesity was defined as BMI >35 kg/m². Comparisons were made with average weight women (BMI = 19.8 to 26 kg/m²). Results: In the group of obese mothers, there was an increased risk for cardiovascular defects compared with the average weight mothers [adjusted odds ratio (OR) = 1.18; 95% CI, 1.09 to 1.27], which was slightly more pronounced for the severe types of cardiovascular defects (adjusted OR = 1.23; 95% CI, 1.05 to 1.44). With morbid obesity, the OR for cardiovascular defects was 1.40 (95% CI, 1.22 to 1.64), and for severe cardiovascular defects, the OR was 1.69 (95% CI, 1.27 to 2.26). There was an increased risk for all specific defects studied among the obese women, but only ventricular septal defects and atrial septal defects reached statistical significance. Discussion: In this sample, a positive association was found between maternal obesity in early pregnancy and congenital heart defects in the offspring. A suggested explanation is undetected type 2 diabetes in early pregnancy, but other explanations may exist.     

Maternal influenza immunization and reduced likelihood of prematurity and small for gestational age births: a retrospective cohort study

Background

Infections during pregnancy have the potential to adversely impact birth outcomes. We evaluated the association between receipt of inactivated influenza vaccine during pregnancy and prematurity and small for gestational age (SGA) births.

Methods and Findings

We conducted a cohort analysis of surveillance data from the Georgia (United States) Pregnancy Risk Assessment Monitoring System. Among 4,326 live births between 1 June 2004 and 30 September 2006, maternal influenza vaccine information was available for 4,168 (96.3%). The primary intervention evaluated in this study was receipt of influenza vaccine during any trimester of pregnancy. The main outcome measures were prematurity (gestational age at birth <37 wk) and SGA (birth weight <10th percentile for gestational age). Infants who were born during the putative influenza season (1 October–31 May) and whose mothers were vaccinated against influenza during pregnancy were less likely to be premature compared to infants of unvaccinated mothers born in the same period (adjusted odds ratio [OR] = 0.60; 95% CI, 0.38–0.94). The magnitude of association between maternal influenza vaccine receipt and reduced likelihood of prematurity increased during the period of at least local influenza activity (adjusted OR = 0.44; 95% CI, 0.26–0.73) and was greatest during the widespread influenza activity period (adjusted OR = 0.28; 95% CI, 0.11–0.74). Compared with newborns of unvaccinated women, newborns of vaccinated mothers had 69% lower odds of being SGA (adjusted OR = 0.31; 95% CI, 0.13–0.75) during the period of widespread influenza activity. The adjusted and unadjusted ORs were not significant for the pre-influenza activity period.

Conclusions

This study demonstrates an association between immunization with the inactivated influenza vaccine during pregnancy and reduced likelihood of prematurity during local, regional, and widespread influenza activity periods. However, no associations were found for the pre-influenza activity period. Moreover, during the period of widespread influenza activity there was an association between maternal receipt of influenza vaccine and reduced likelihood of SGA birth. Please see later in the article for the Editors'' Summary     

Early pregnancy azathioprine use and pregnancy outcomes

BACKGROUND: Azathioprine (AZA) is used during pregnancy by women with inflammatory bowel disease (IBD), other autoimmune disorders, malignancy, and organ transplantation. Previous studies have demonstrated potential risks. METHODS: The Swedish Medical Birth Register was used to identify 476 women who reported the use of AZA in early pregnancy. The effect of AZA exposure on pregnancy outcomes was studied after adjustment for maternal characteristics that could act as confounders. RESULTS: The most common indication for AZA use was IBD. The rate of congenital malformations was 6.2% in the AZA group and 4.7% among all infants born (adjusted OR: 1.41, 95% CI: 0.98–2.04). An association between early pregnancy AZA exposure and ventricular/atrial septal defects was found (adjusted OR: 3.18, 95% CI: 1.45–6.04). Exposed infants were also more likely to be preterm, to weigh <2500 gm, and to be small for gestational age compared to all infants born. This effect remained for preterm birth and low birth weight when infants of women with IBD but without AZA exposure were used as a comparison group. A trend toward an increased risk of congenital malformations was found among infants of women with IBD using AZA compared to women with IBD not using AZA (adjusted OR: 1.42, 95% CI: 0.93–2.18). CONCLUSIONS: Infants exposed to AZA in early pregnancy may be at a moderately increased risk of congenital malformations, specifically ventricular/atrial septal defects. There is also an increased risk of growth restriction and preterm delivery. These associations may be confounded by the severity of maternal illness. Birth Defects Research (Part A), 2009. © 2009 Wiley‐Liss, Inc.     

Factors Associated with Influenza Vaccination of Hospitalized Elderly Patients in Spain

Vaccination of the elderly is an important factor in limiting the impact of influenza in the community. The aim of this study was to investigate the factors associated with influenza vaccination coverage in hospitalized patients aged ≥65 years hospitalized due to causes unrelated to influenza in Spain. We carried out a cross-sectional study. Bivariate analysis was performed comparing vaccinated and unvaccinated patients, taking in to account sociodemographic variables and medical risk conditions. Multivariate analysis was performed using multilevel regression models. We included 1038 patients: 602 (58%) had received the influenza vaccine in the 2013–14 season. Three or more general practitioner visits (OR = 1.61; 95% CI 1.19–2.18); influenza vaccination in any of the 3 previous seasons (OR = 13.57; 95% CI 9.45–19.48); and 23-valent pneumococcal polysaccharide vaccination (OR = 1.97; 95% CI 1.38–2.80) were associated with receiving the influenza vaccine. Vaccination coverage of hospitalized elderly people is low in Spain and some predisposing characteristics influence vaccination coverage. Healthcare workers should take these characteristics into account and be encouraged to proactively propose influenza vaccination to all patients aged ≥65 years.     

Simulations of rubella vaccination strategies in China

Many infants whose mothers have rubella infections during their first trimester of pregnancy have birth defects called congenital rubella syndrome (CRS). China does not routinely vaccinate against rubella in the public sector, but may need to start as its 'one child per couple' policy changes the population age distribution and the dynamics of rubella epidemiology, so that the incidence of rubella in pregnant women increases. Computer simulations with demographic transitions and rubella transmission dynamics predict that, with no or limited rubella vaccination, CRS incidence in China in the 30 years after 2020 will be more than twice the level in 2005. Comparisons of rubella vaccination strategies using computer simulations show that routine vaccination of over 80% of 1-year-old children would be effective in reducing total CRS cases in 2005-2051 and eliminating rubella in China by 2051. Routine immunizations at higher levels and the addition of early mass vaccinations of 2-14-year-old children and women of childbearing ages would further reduce total CRS cases and speed up the elimination of rubella.     

Influenza vaccination,pneumococcal vaccination and risk of acute myocardial infarction: matched case–control study

Background

Previous studies have shown an association between acute myocardial infarction and preceding respiratory infection. Contradictory evidence exists on the influence of influenza vaccination and pneumococcal vaccination in preventing cardiovascular disease. We aimed to investigate the possible association of influenza vaccination and pneumococcal vaccination with acute myocardial infarction.

Methods

We used a matched case–control design with data from the United Kingdom General Practice Research Database. Cases were patients who were at least 40 years of age at diagnosis of first acute myocardial infarction recorded from Nov.1, 2001, to May 31, 2007, and were matched for sex, general practice, age and calendar time (i.e., month corresponding to index date of acute myocardial infarction), with up to four controls each. Data were analyzed using conditional logistic regression, adjusted for vaccination target groups, cardiovascular risk factors, treatment medications and attendances at a general practice.

Results

We included 78 706 patients, of whom 16 012 were cases and 62 694 were matched controls. Influenza vaccination had been received in the previous year by 8472 cases (52.9%) and 32 081 controls (51.2%) and was associated with a 19% reduction in the rate of acute myocardial infarction (adjusted odds ratio [OR] 0.81, 95% confidence interval [CI] 0.77–0.85). Early seasonal influenza vaccination was associated with a lower rate of acute myocardial infarction (adjusted OR 0.79, 95% CI 0.75–0.83) than vaccination after mid-November (adjusted OR 0.88, 95% CI 0.79–0.97). Pneumococcal vaccination was not associated with a reduction in the rate of acute myocardial infarction (adjusted OR 0.96, 95% CI 0.91–1.02).

Interpretation

Influenza vaccination but not pneumococcal vaccination is associated with a reduced rate of first acute myocardial infarction. This association and the potential benefit of early seasonal vaccination need to be considered in future experimental studies.Winter peaks in incidence of acute myocardial infarction have been linked to climate,¹ metabolic factors² and infection.³ Because known risk factors do not fully account for cases of acute myocardial infarction, current interest is focused on the putative link with respiratory infection. Significant increases in acute myocardial infarction occur during peak winter incidence of pneumonia, influenza and influenza-like syndrome,⁴ particularly during years dominated by epidemic rather than nonepidemic influenza A. This association supports the notion that the increase is caused by influenza rather than cold weather.⁵Acute myocardial infarction may increase susceptibility to respiratory illness,⁶ but the association between acute myocardial infarction and respiratory infection occurring within four weeks prior to the acute myocardial infarction^7,8 supports infection as a cause of acute myocardial infarction. Although the exact mechanism is unknown, the favoured hypothesis is that infection triggers plaque rupture.⁹ Although several observational studies, as well as two randomized controlled trials,^10,11 suggest a positive effect of influenza vaccine in preventing acute myocardial infarction, they provide insufficient and conflicting evidence.¹²The aim of this study was to investigate a possible association between influenza or pneumococcal vaccination and acute myocardial infarction.     

Influenza Vaccine Effectiveness against Hospitalisation with Confirmed Influenza in the 2010–11 Seasons: A Test-negative Observational Study

Immunisation programs are designed to reduce serious morbidity and mortality from influenza, but most evidence supporting the effectiveness of this intervention has focused on disease in the community or in primary care settings. We aimed to examine the effectiveness of influenza vaccination against hospitalisation with confirmed influenza. We compared influenza vaccination status in patients hospitalised with PCR-confirmed influenza with patients hospitalised with influenza-negative respiratory infections in an Australian sentinel surveillance system. Vaccine effectiveness was estimated from the odds ratio of vaccination in cases and controls. We performed both simple multivariate regression and a stratified analysis based on propensity score of vaccination. Vaccination status was ascertained in 333 of 598 patients with confirmed influenza and 785 of 1384 test-negative patients. Overall estimated crude vaccine effectiveness was 57% (41%, 68%). After adjusting for age, chronic comorbidities and pregnancy status, the estimated vaccine effectiveness was 37% (95% CI: 12%, 55%). In an analysis accounting for a propensity score for vaccination, the estimated vaccine effectiveness was 48.3% (95% CI: 30.0, 61.8%). Influenza vaccination was moderately protective against hospitalisation with influenza in the 2010 and 2011 seasons.     

The social network around influenza vaccination in health care workers: a cross-sectional study

Background

Influenza vaccination coverage remains low among health care workers (HCWs) in many health facilities. This study describes the social network defined by HCWs’ conversations around an influenza vaccination campaign in order to describe the role played by vaccination behavior and other HCW characteristics in the configuration of the links among subjects.

Methods

This study used cross-sectional data from 235 HCWs interviewed after the 2010/2011 influenza vaccination campaign at the Hospital Clinic of Barcelona (HCB), Spain. The study asked: “Who did you talk to or share some activity with respect to the seasonal vaccination campaign?” Variables studied included sociodemographic characteristics and reported conversations among HCWs during the influenza campaign. Exponential random graph models (ERGM) were used to assess the role of shared characteristics (homophily) and individual characteristics in the social network around the influenza vaccination campaign.

Results

Links were more likely between HCWs who shared the same professional category (OR 3.13, 95% CI?=?2.61–3.75), sex (OR 1.34, 95% CI?=?1.09–1.62), age (OR 0.7, 95% CI?=?0.63–0.78 per decade of difference), and department (OR 11.35, 95% CI?=?8.17–15.64), but not between HCWs who shared the same vaccination behavior (OR 1.02, 95% CI?=?0.86–1.22). Older (OR 1.26, 95% CI?=?1.14–1.39 per extra decade of HCW) and vaccinated (OR 1.32, 95% CI?=?1.09–1.62) HCWs were more likely to be named.

Conclusions

This study finds that there is no homophily by vaccination status in whom HCWs speak to or interact with about a workplace vaccination promotion campaign. This result highlights the relevance of social network analysis in the planning of health promotion interventions.

     

A case-control study of vanishing twin as a risk factor for cerebral palsy.

It has been hypothesized that cerebral palsy of unknown etiology is the result of the death of an unrecognized co-twin--a vanishing twin--in early gestation. We conducted a case-control study of vanishing twin as a risk factor for cerebral palsy of unknown etiology in women who had an obstetric ultrasound during pregnancy. Among mothers of cases, one of 86 had evidence of a vanishing twin on ultrasound, as compared to two of 381 control mothers (odds ratio [OR] 2.2, 95% confidence interval [CI] 0.2-24.8; p = 0.5). Bleeding in early pregnancy, which may indicate the loss of a co-twin, was reported by 14 case mothers and 46 control mothers (OR 1.6, 95% CI 0.8-3.0; p = 0.3). On the basis of results presented here, the vanishing twin syndrome is unlikely to account for a high proportion of cases of cerebral palsy, but there is insufficient statistical power to draw firm conclusions.     

Orofacial clefts and infections during pregnancy

Orofacial clefts (OFCs) are common congenital malformations of the lip, palate, or both caused by complex genetic and environmental factors. Specific antibodies against viruses influenza, rubella, cytomegalovirus, Epstein-Barr, parotitis and hepatitis B were investigated serologically in children with orofacial clefts and in their mothers. The results were compared with those obtained in control children and their mothers. Evaluation of the results and their statistical processing supports the assumption that infection during pregnancy may have occurred in the series studied induced by viruses of influenza, rubella, cytomegalovirus and possibly also by the Epstein-Barr virus. No association with the viruses of hepatitis B and parotitis was established.     

Maternal birthplace and major congenital malformations among New York Hispanics

BACKGROUND: Little is known about the association between maternal nativity and congenital malformations among Hispanics living in the United States. METHODS: We conducted a cross-sectional study to investigate the association between maternal nativity and various congenital malformations among singleton live-births born to Hispanic women in New York from 1993 to 2001. Birth certificates, used to identify maternal birthplace, were linked with congenital malformation registry files to obtain birth defects outcome. We examined how the risk of birth defects varied by maternal birthplace by estimating the adjusted odds ratios (aORs) using logistic regression. RESULTS: A foreign maternal birth showed statistically negative associations with overall congenital malformations (aOR, 0.70; 95% CI, 0.68-0.73), cardiovascular defects (aOR, 0.85; 95% CI, 0.77-0.93), central nervous system defects (aOR, 0.76; 95% CI, 0.63-0.91), and multiple defects (aOR, 0.80; 95% CI, 0.74-0.86). Specifically, foreign-born Hispanic women were statistically at reduced risk to deliver live babies with cleft palate (aOR, 0.56; 95% CI, 0.40-0.80), atresia and stenosis of rectum or anus (aOR, 0.58; 95% CI, 0.35-0.97), and craniosynostosis (aOR, 0.71; 95% CI, 0.51-0.99). Hispanic mothers born in Puerto Rico had a similar risk of delivering children with birth defects compared to U.S.-born Hispanic mothers. In contrast, Hispanic mothers born in Mexico, or Cuba and Central and South America were at reduced risk of delivering infants with overall congenital malformations (aOR, 0.64; 95% CI, 0.60-0.67) and (aOR, 0.65; 95% CI, 0.63-0.68), respectively. CONCLUSIONS: Foreign-born Hispanic mothers had a slightly lower risk to deliver live-born singleton infants with major congenital malformations than did U.S. born Hispanic mothers.     

Immunogenicity and Safety of Influenza Vaccination in Systemic Lupus Erythematosus Patients Compared with Healthy Controls: A Meta-Analysis

Objective

To assess the immunogenicity and safety of influenza vaccine in patients with systemic lupus erythematosus (SLE).

Methods

Relevant articles were retrieved from electronic databases. Seroprotection rate, seroconversion rate and factors that increase antibody geometric mean titer (GMT) were used as indices to measure the immunogenicity. The safety of vaccine was assessed through monitoring adverse events, which included side effects and SLE exacerbations. We performed a meta-analysis of influenza vaccine seroprotection, seroconversion and adverse effects. SLE exacerbation after vaccination was comprehensively described. We used the Committee for Proprietary Medicinal Products (CPMP) guidelines to determine whether influenza can induce adequate immunogenicity in patients with SLE.

Results

Eighteen studies with 1966 subjects met the inclusion criteria. At least 565 of the subjects were patients with low-to-moderate SLE Disease Activity Index (SLEDAI) score or stable SLE disease. Compared with the general population, seroprotection rate in SLE patients was significantly decreased in patients with H1N1 [odds ratio (OR) = 0.36, 95% confidence interval (CI): 0.27–0.50] and H3N2 vaccination (OR = 0.48, 95% CI: 0.24–0.93), but not influenza B vaccination (OR = 0.55, 95% CI: 0.24–1.25). Seroconversion rate also significantly decreased in patients with H1N1 (OR = 0.39, 95% CI: 0.27–0.57) and influenza B (OR = 0.47, 95% CI: 0.29–0.76) vaccination, but not H3N2 vaccination (OR = 0.62, 95% CI: 0.21–1.79). However, the immunogenicity of influenza vaccine in SLE patients almost reached that of the CPMP guidelines. The OR for side effects (patients versus healthy controls) was 3.24 (95% CI: 0.62–16.76). Among 1966 patients with SLE, 32 experienced mild exacerbation of SLE and five had serious side effects for other reasons.

Conclusion

Influenza vaccine has moderate effect on protecting patients with SLE. The side effects of influenza vaccine are not serious and are manageable. With consideration of a higher risk of SLE exacerbation and a more severe course of infection among SLE patients, influenza vaccination should be promoted among SLE patients with a low-to-moderate SLEDAI score or stable disease.     

Effectiveness of the 2012/13 Trivalent Live and Inactivated Influenza Vaccines in Children and Adolescents in Saxony-Anhalt,Germany: A Test-Negative Case-Control Study

A live attenuated influenza vaccine has been available in Germany since the influenza season 2012/13, which is approved for children aged 2-17 years. Using data from our laboratory-based surveillance system, we described the circulation of influenza and non-influenza respiratory viruses during the influenza season 2012/13 in Saxony-Anhalt. We estimated the effectiveness of live and inactivated trivalent influenza vaccines in preventing laboratory-confirmed cases among children and adolescents. From week 40/2012 to 19/2013, sentinel paediatricians systematically swabbed acute respiratory illness patients for testing of influenza and 5 non-influenza viruses by PCR. We compared influenza cases and influenza-negative controls. Among children aged 2-17 years, we calculated overall and vaccine type-specific effectiveness against laboratory-confirmed influenza, stratified by age group (2-6; 7-17 years). We used multivariable logistic regression to adjust estimates for age group, sex and month of illness. Out of 1,307 specimens, 647 (35%) were positive for influenza viruses and 189 (15%) for at least one of the tested non-influenza viruses. For vaccine effectiveness estimation, we included 834 patients (mean age 7.3 years, 53% males) in our analysis. Of 347 (42%) influenza-positive specimens, 61 (18%) were positive for A(H1N1)pdm09, 112 (32%) for A(H3N2) and 174 (50%) for influenza B virus. The adjusted overall vaccine effectiveness including both age groups was 38% (95% CI: 0.8-61%). The adjusted effectiveness for inactivated vaccines was 37% (95% CI: -35-70%) and for live vaccines 84% (95% CI: 45-95%). Effectiveness for the live vaccine was higher in 2-6 year-old children (90%, 95% CI: 20-99%) than in children aged 7-17 years (74%, 95% CI: -32-95%). Our study of the strong influenza season in 2012/13 suggests a high preventive effect of live attenuated influenza vaccine especially among young children, which could not be reached by inactivated vaccines. We recommend the use of live attenuated influenza vaccines in children unless there are contraindications.     

Talipes equinovarus and maternal smoking: a population-based case-control study in Washington state

BACKGROUND: Talipes equinovarus (TEV), also called congenital idiopathic clubfoot, true clubfoot and common clubfoot, is one of the most common major birth defects. Its correction is often difficult and expensive. Its etiology is poorly understood and few analytic epidemiological studies have been devoted to exploring specific risk factors for TEV. METHODS: Our population-based study consists of 239 documented cases of idiopathic TEV obtained from hospital and outpatient sources and 365 controls identified via random digit dialing from five Western Washington counties. Structured maternal interviews were conducted by trained interviewers and multiple logistic regression used to evaluate associations between maternal smoking and birth of a child with TEV. RESULTS: Our study shows strong associations between maternal smoking and idiopathic TEV. Case mothers were more likely to have smoked during pregnancy (OR = 2.2; 95% CI = 1.5, 3.3). Increased TEV risk was seen with increased smoking and estimates ranged from 1.5 for the lightest smokers to 3.9 for the heaviest smokers. Gender specific differences in risk were also noted with risk estimates of 1.8 (95% CI = 1.2, 3.0) for boys whose mothers smoked during pregnancy and 2.8 (95% CI = 1.4, 5.4) for girls. Trends for increased risk with higher numbers of cigarettes were noted for both genders. For isolated TEV, the overall odds ratio (OR) for smoking was 2.4 (95% CI = 1.6, 3.6) with a range from 1.4-4.6. No confounders were noted. CONCLUSIONS: As postulated, maternal smoking during pregnancy appears to increase the risk of having a child with idiopathic clubfoot and the number of cigarettes smoked influence that risk. Further delineation of dose-response is warranted as are continued efforts to decrease maternal smoking during pregnancy.