[False beliefs about vaccines]. / Falsas creencias sobre las vacunas.

Vaccines are an essential tool for the prevention of infectious diseases. However, false ideas and rumours with no scientific foundation about their possible negative effects may dissuade people from being vaccinated, with the consequent risks for the health of the population. The objective of this article is to evaluate the origin and the arguments of some of the most frequent mistaken ideas and rumours about the possible adverse effects of vaccines. Some clearly established adverse effects are presented, as well as false beliefs about various vaccines and potential harm to health. Vaccines, like any drug, can cause adverse effects, but the possible adverse effects of vaccination programs are clearly lower than their individual (vaccinated) and collective benefits (those vaccinated and those who cannot be vaccinated for medical reasons). The possible adverse effects attributable to vaccines should be detected by powerful and well-structured pharmacovigilance systems.

A Composite of Functional Status and Pneumonia Severity Index Improves the Prediction of Pneumonia Mortality in Older Patients.

BACKGROUND: The baseline health status may be a determinant of interest in the evolution of pneumonia. OBJECTIVE: Our objective was to assess the predictive ability of community-acquired pneumonia (CAP) mortality by combining the Barthel Index (BI) and Pneumonia Severity Index (PSI) in patients aged ≥ 65 years. DESIGN, PATIENTS AND MAIN MEASURES: In this prospective, observational, multicenter analysis of comorbidities, the clinical data, additional examinations and severity of CAP were measured by the PSI and functional status by the BI. Two multivariable models were generated: Model 1 including the PSI and BI and model 2 with PSI plus BI stratified categorically. KEY RESULTS: The total population was 1919 patients, of whom 61% had severe pneumonia (PSI IV-V) and 40.4% had some degree of dependence (BI ≤ 90 points). Mortality in the PSI V-IV group was 12.5%. Some degree of dependence was associated with increased mortality in both the mild (7.2% vs. 3.2%; p = 0.016) and severe (14% vs. 3.3%; p < 0.001) pneumonia groups. The combination of PSI IV-V and BI ≤ 90 was the greatest risk factor for mortality (aOR 4.17; 95% CI 2.48 to 7.02) in our series. CONCLUSIONS: The use of a bimodal model to assess CAP mortality (PSI + BI) provides more accurate prognostic information than the use of each index separately.

Repeated influenza vaccination for preventing severe and fatal influenza infection in older adults: a multicentre case-control study.

BACKGROUND: The effectiveness of repeated vaccination for influenza to prevent severe cases remains unclear. We evaluated the effectiveness of influenza vaccination on preventing admissions to hospital for influenza and reducing disease severity. METHODS: We conducted a case-control study in 20 hospitals in Spain during the 2013/14 and 2014/15 influenza seasons. Community-dwelling adults aged 65 years or older who were admitted to hospital for laboratory-confirmed influenza were matched with inpatient controls by sex, age, hospital and admission date. The effectiveness of vaccination in the current and 3 previous seasons in preventing influenza was estimated for inpatients with nonsevere influenza and for those with severe influenza who were admitted to intensive care units (ICUs) or who died. RESULTS: We enrolled 130 inpatients with severe and 598 with nonsevere influenza who were matched to 333 and 1493 controls, respectively. Compared with patients who were unvaccinated in the current and 3 previous seasons, adjusted effectiveness of influenza vaccination in the current and any previous season was 31% (95% confidence interval [CI] 13%-46%) in preventing admission to hospital for nonsevere influenza, 74% (95% CI 42%-88%) in preventing admissions to ICU and 70% (95% CI 34%-87%) in preventing death. Vaccination in the current season only had no significant effect on cases of severe influenza. Among inpatients with influenza, vaccination in the current and any previous season reduced the risk of severe outcomes (adjusted odds ratio 0.45, 95% CI 0.26-0.76). INTERPRETATION: Among older adults, repeated vaccination for influenza was twice as effective in preventing severe influenza compared with nonsevere influenza in patients who were admitted to hospital, which is attributable to the combination of the number of admissions to hospital for influenza that were prevented and reduced disease severity. These results reinforce recommendations for annual vaccination for influenza in older adults.

Asthma and influenza vaccination in elderly hospitalized patients: Matched case-control study in Spain.

OBJECTIVES: Influenza infection is an exacerbating factor for asthma, and its prevention is critical in managing asthmatic patients. We investigated the effect of influenza vaccination on asthmatic and non-asthmatic patients hospitalized with laboratory-confirmed influenza in Spain. METHODS: We made a matched case-control study to assess the frequency of hospitalization for influenza in people aged ≥65 years. Hospitalized patients with unplanned hospital admissions were recruited from 20 hospitals representing seven Spanish regions. Cases were defined as those hospitalized due to a laboratory-confirmed influenza infection and controls were matched by age, sex, and hospital. Data were obtained from clinical records, and patients stratified by clinical asthma history. Vaccination status and asthma due to influenza infection were analyzed according to sociodemographic variables and medical risk conditions. Multivariable analysis was made using conditional logistic regression models. RESULTS: 582 hospitalized patients with influenza (15.8% asthmatic) and 1,570 hospitalized patients without influenza (7.9% asthmatic) were included. In the multivariable conditional logistic regression using unvaccinated and non-asthmatic patients as the reference group, vaccination significantly prevented influenza in non-asthmatic patients (aOR = 0.63; 95% CI: 0.45, 0.88) and also showed a trend for a possibly protective effect in asthmatic patients (aOR = 0.79; 95% CI: 0.34, 1.81). CONCLUSION: Our results suggest that influenza vaccination could be a protective factor for asthmatic patients, although the results are inconclusive and further research is required. Practically, given the better clinical evolution of vaccinated asthma cases, and the lack of better evidence, the emphasis on vaccination of this group should continue.

Smoking may increase the risk of influenza hospitalization and reduce influenza vaccine effectiveness in the elderly.

Background: Through its effects on the immune system, smoking may facilitate influenza virus infection, its severity and its most frequent complications. The objective was to investigate the smoking history as a risk factor for influenza hospitalization and influenza vaccine effectiveness in elderly smokers/ex-smokers and non-smokers. Methods: We carried out a multicenter case-control study in the 2013-2014 and 2014-2015 influenza seasons. Cases aged ≥65 years and age-, sex-matched controls were selected from 20 Spanish hospitals. We collected epidemiological variables, comorbidities, vaccination history and the smoking history. The risk of hospitalization due to smoking (current smokers and ex-smokers) was determined using the adjusted odds ratio (aOR) with conditional logistic regression models. Vaccine effectiveness (VE) was calculated using the formula: VE = (1 - aOR) × 100. Results: We studied 728 cases and 1826 controls. Cases had a higher frequency of smoking (47.4% vs 42.1%). Smoking was associated with an increased risk of influenza hospitalization (aOR = 1.32, 95% CI: 1.04-1.68). Influenza vaccine effectiveness in preventing hospitalization was 21% (95% CI: -2 to 39) in current/ex-smokers and 39% in non-smokers (95% CI: 22-52). Conclusions: A history of smoking may increase the risk of hospitalization in smokers and ex-smokers. Preventing smoking could reduce hospitalizations due to influenza. Smokers and ex-smokers should be informed of the risk of hospitalization due to influenza infection, and encouraged to stop smoking. Smokers should be considered an at-risk group to be aggressively targeted for routine influenza vaccination.

Asthma in older people hospitalized with influenza in Spain: A case-control study.

BACKGROUND: Influenza infection is an exacerbating factor for asthma, and its prevention is critical in older patients with asthma. OBJECTIVE: This study investigated the association between asthma and influenza-related hospitalization, in Spain, of patients ages ≥ 65 years and their clinical evolution. METHODS: A multicenter case-control study was carried out in 20 Spanish hospitals during the 2013-2014 and 2014-2015 influenza seasons. Patients ages ≥ 65 years hospitalized with laboratory-confirmed influenza with and without asthma were matched with controls according to the presence of asthma, sex, age, hospital, and date of hospitalization. RESULTS: A total of 561 patients with influenza (15.9% with asthma) and 1258 patients without influenza (8.0% with asthma) were included as cases and controls, respectively. The adjusted risk of influenza for patients with asthma was calculated by multivariate conditional logistic regression. The adjustment variables were the following: smoker/nonsmoker, pneumonia in the 2 years before hospital admission, previous oral treatment with corticosteroids, influenza vaccination during the seasonal campaign, Barthel index (ordinal scale used to measure performance in activities of daily living), level of education, obesity, and the presence of other comorbidities. Patients with asthma presented a great risk of influenza (adjusted odds ratio 2.64 [95% confidence interval, 1.77-3.94]). Compared with patients without asthma, patients with asthma had more symptoms, and these had been present for longer before admission but presented a lower hospital or postdischarge mortality. CONCLUSION: This study indicated that asthma was associated with hospitalization from influenza A infection. Although patients with asthma and with influenza had more symptoms, hospital or postdischarge mortality was lower, probably due to a better response to medical treatment.

The effectiveness of influenza vaccination in preventing hospitalisations of elderly individuals in two influenza seasons: a multicentre case-control study, Spain, 2013/14 and 2014/15.

Influenza vaccination may limit the impact of influenza in the community. The aim of this study was to assess the effectiveness of influenza vaccination in preventing hospitalisation in individuals aged ≥ 65 years in Spain. A multicentre case-control study was conducted in 20 Spanish hospitals during 2013/14 and 2014/15. Patients aged ≥ 65 years who were hospitalised with laboratory-confirmed influenza were matched with controls according to sex, age and date of hospitalisation. Adjusted vaccine effectiveness (VE) was calculated by multivariate conditional logistic regression. A total of 728 cases and 1,826 matched controls were included in the study. Overall VE was 36% (95% confidence interval (CI): 22-47). VE was 51% (95% CI: 15-71) in patients without high-risk medical conditions and 30% (95% CI: 14-44) in patients with them. VE was 39% (95% CI: 20-53) in patients aged 65-79 years and 34% (95% CI: 11-51) in patients aged ≥ 80 years, and was greater against the influenza A(H1N1)pdm09 subtype than the A(H3N2) subtype. Influenza vaccination was effective in preventing hospitalisations of elderly individuals.

Factors associated with acceptance of pandemic flu vaccine by healthcare professionals in Spain, 2009-2010.

The A(H1N1)pdm09 influenza virus reached pandemic level in Spain in 2009, prompting a national vaccination campaign. To avoid transmission to patients, healthcare professionals' vaccination against pandemic influenza is crucial. The main objective of this study was to analyze factors associated with the failure by healthcare professionals to accept the pandemic vaccination in 2009. A cross-sectional survey was conducted of healthcare professionals in seven of Spain's autonomous regions. A questionnaire was used to collect information about personal and professional details, the respondents' flu vaccination status in the 2008-2009 and 2009-2010 seasons (seasonal and pandemic vaccines), and their knowledge and attitudes. A total of 1,661 professionals completed the survey. In the 2009-2010 season, 38.2% had both the seasonal and the pandemic vaccine, 22.1% had had only the seasonal, and 4.7% only the pandemic vaccine. The strongest predictor of not receiving the pandemic vaccine was not having had seasonal vaccinations in that year or the previous year. Those who had not received the pandemic vaccine were more often female; nurses; under 45; denied contact with at-risk groups; and had negative beliefs about the vaccine effectiveness and little concern for getting the disease, being infected at work, or passing it on to patients. It would be prudent to direct preventive campaigns not only at individuals at risk of catching flu but also at health professionals with a negative view of flu vaccine, with a particular focus on nurses, who have a key role in recommending flu vaccine.

A single-day point-prevalence study of faecal carriers in long-term care hospitals in Madrid (Spain) depicts a complex clonal and polyclonal dissemination of carbapenemase-producing Enterobacteriaceae.

OBJECTIVES: The objective of this study was to describe the prevalence and microbiological characteristics of carbapenemase-producing Enterobacteriaceae (CPE) colonizing patients in long-term care hospitals (LTCHs) in Madrid, Spain. METHODS: Three LTCHs were included in a single-day point-prevalence survey (September 2013). Rectal swabs, collected from all hospitalized patients (137 in LTCH-A, 121 in LTCH-B and 83 in LTCH-C), were plated onto chromogenic media. Population structure (PFGE and MLST), genes encoding carbapenemases and ESBLs and plasmids carrying carbapenemase genes were characterized. RESULTS: The prevalence of CPE carriers was 4.1% (14/341) [2.9% (4/137), LTCH-A; 4.1% (5/121), LTCH-B; and 6.0% (5/83), LTCH-C]. OXA-48 was the most prevalent carbapenemase (nine Klebsiella pneumoniae, two Escherichia coli, one Enterobacter cloacae and one Citrobacter braakii) followed by VIM-1 (one K. pneumoniae and one Raoultella ornithinolytica). One patient (LTCH-C) was co-colonized with OXA-48-producing K. pneumoniae and E. coli. K. pneumoniae and E. coli isolates also coproduced CTX-M-15 (n = 11) or CTX-M-9 (n = 1) enzymes. K. pneumoniae clustered into six PFGE types corresponding to ST11 (n = 1), ST15 (n = 6), ST307 (n = 1) and ST405 (n = 2). E. coli from LTCH-A and LTCH-C exhibited two different PFGE types associated with ST68. OXA-48 and VIM-1 enzymes were found in different clones in LTCH-A and LTCH-C. However, OXA-48 was the only carbapenemase detected in LTCH-B, mainly associated with K. pneumoniae ST15. KPC, IMP and NDM enzymes were not detected. blaOXA-48 was located on an ∼ 60 kb plasmid with a pOXA-48a-IncL/M backbone. CONCLUSIONS: We describe the first point-prevalence study of CPE faecal carriers in LTCHs in Spain. OXA-48, the most prevalent carbapenemase, showed a complex dissemination pattern with clonal and polyclonal bacterial populations.

Effect of Occupational Exposure on A(H1N1)pdm09 Infection and Hospitalization.

OBJECTIVE: To analyze relationships between occupational exposure and influenza infection and hospitalization during the 2009-2010 pandemic wave and the 2010-2011 influenza seasonal epidemic in Spain. METHODS: Occupations were classified as high, medium, or low risk of influenza exposure. To assess the risk of infection, 588 outpatient cases of influenza confirmed by reverse-transcription polymerase-chain-reaction (RT-PCR) were compared with 588 outpatients without influenza symptoms. To assess the risk of hospitalization, 337 outpatient influenza cases were compared with 337 inpatient influenza cases. RESULTS: The high risk of occupational exposure group was composed only of health care workers. After adjustment for age, sex, vaccination status, and predictive variables of influenza infection, patients with a high risk of occupational exposure had an aOR of 2.14 (95%CI: 1.25-3.66) of being an outpatient influenza case and an aOR of 0.43 (95%CI: 0.20-0.95) of being an inpatient influenza case, compared with those with a low risk. CONCLUSIONS: A high risk of occupational exposure is a risk factor for influenza infection but not for hospitalization.

Comparison of body mass index (BMI) with the CUN-BAE body adiposity estimator in the prediction of hypertension and type 2 diabetes.

BACKGROUND: Obesity is a world-wide epidemic whose prevalence is underestimated by BMI measurements, but CUN-BAE (Clínica Universidad de Navarra - Body Adiposity Estimator) estimates the percentage of body fat (BF) while incorporating information on sex and age, thus giving a better match. Our aim is to compare the BMI and CUN-BAE in determining the population attributable fraction (AFp) for obesity as a cause of chronic diseases. METHODS: We calculated the Pearson correlation coefficient between BMI and CUN-BAE, the Kappa index and the internal validity of the BMI. The risks of arterial hypertension (AHT) and diabetes mellitus (DM) and the AFp for obesity were assessed using both the BMI and CUN-BAE. RESULTS: 3888 white subjects were investigated. The overall correlation between BMI and CUN-BAE was R(2) = 0.48, which improved when sex and age were taken into account (R(2) > 0.90). The Kappa coefficient for diagnosis of obesity was low (28.7 %). The AFp was 50 % higher for DM and double for AHT when CUN-BAE was used. CONCLUSIONS: The overall correlation between BMI and CUN-BAE was not good. The AFp of obesity for AHT and DM may be underestimated if assessed using the BMI, as may the prevalence of obesity when estimated from the percentage of BF.

Smoking may increase the risk of hospitalization due to influenza.

BACKGROUND: Smoking may facilitate influenza virus infections and their severity. The objective was to investigate the risk of hospitalization due to influenza in Spanish smokers and ex-smokers. METHODS: We carried out a multicentre, case-control study in 2011. Cases [patients ≥ 18 years hospitalized > 24 h with real time polymerase chain reaction (RT-PCR)-confirmed influenza] were selected from 29 Spanish hospitals. For each case, we selected an outpatient aged ≥ 18 years with RT-PCR-confirmed influenza matched by age (±5 years), date of hospitalization of the case (±10 days) and province of residence. We collected epidemiological variables, comorbidities and the smoking history. The risk of hospitalization due to smoking was determined by the adjusted odds ratio (aOR) using logistic regression. RESULTS: We studied 471 hospitalized cases and 476 outpatient cases. Hospitalized cases had a higher frequency of influenza risk factors compared with outpatient cases. Hospitalized cases had a higher frequency of smoking (30.9% vs. 17.1%) and being ex-smokers (29.3% vs. 25.3%). Current smoking (aOR = 2.18, 95% CI: 1.23-3.87) and being an ex-smoker (aOR = 1.73, 95% CI: 1.07-2.82) were associated with the risk of hospitalization. CONCLUSIONS: Smoking may increase the risk of hospitalization in smokers and ex-smokers when infected by the influenza virus. Smoking prevention could reduce hospitalizations. Influenza vaccination is recommended for smokers.

Influenza vaccination of primary healthcare physicians may be associated with vaccination in their patients: a vaccination coverage study.

BACKGROUND: To assess the contribution of physician-related factors, especially their influenza vaccine status, in the vaccination coverage of their patients. METHODS: A study of vaccination coverage was carried out in Spain in 2011-12. The dependent variable (vaccination coverage in patients aged ≥ 65 years) was obtained from regional records. Information was gathered on the vaccination of physicians through an anonymous web survey. We compared the vaccination coverage of patients with the vaccination of their physicians using the Student t test. Associations were determined using a multilevel regression model. RESULTS: The coverage in patients aged ≥ 65 years was 56.3% and was higher (57.3%) in patients whose physician had been vaccinated than in those whose physician had not (55.2%) (p = 0.008). In the multilevel regression model, vaccination of the physician was associated (p = 0.049) with vaccination of their patients after controlling for the effects of age (p = 0.046), region (p = 0.089), and opinions on the effectiveness of the vaccine (p = 0.013). CONCLUSIONS: Vaccination of physicians together with their opinions on the effectiveness of the vaccine may be a predictor of vaccination coverage in their patients. Further studies are required to confirm this.

Pandemic influenza A (H1N1) in non-vaccinated, pregnant women in Spain (2009-2010).

The aim of this study was to investigate the main characteristics of non-vaccinated pregnant women who were hospitalised for influenza A (H1N1) pdm09 pandemic versus pregnant women hospitalised for non-influenza-related reasons in Spain, and to characterise the clinical presentation of the disease in this population to facilitate early diagnosis and future action programmes. Understanding influenza infection during pregnancy is important as pregnant women are a high-risk population for increased morbidity from influenza infection. We investigated the socio-demographic and clinical features of 51 non-vaccinated, pregnant women infected with the pandemic influenza A (H1N1) virus in Spain (cases) and compared them to 114 controls (non-vaccinated and non-infected pregnant women) aged 15-44 years. Substantial and significant odd ratios (ORs) for pandemic influenza A (H1N1) were found for the pregnant women who were obese compared with controls (body mass index > 30) (OR 3.03; 95% confidence intervals 1.13-8.11). The more prevalent symptoms observed in pandemic influenza-infected pregnant women were high temperature, cough (82.4%), malaise (80.5%), myalgia (56.1%), and headaches (54.9%). Our results suggest that the initial symptoms and risk factors for infection of pregnant women with the influenza A (H1N1) pdm09 virus are similar to the symptoms and risk factors for seasonal influenza, which make early diagnosis difficult, and reinforces the need to identify and protect high-risk groups.

Predictive factors of severe multilobar pneumonia and shock in patients with influenza.

PURPOSE: To identify risk factors present at admission in adult patients hospitalised due to influenza virus infection during the 2009/10 and 2010/11 seasons--including whether infection was from pandemic or seasonal influenza A infections--that were associated with the likelihood of developing severe pneumonia with multilobar involvement and shock. METHODS: Prospective cohort study. Patients hospitalised due to influenza virus infection were recruited. We collected information on sociodemographic characteristics, pre-existing medical conditions, vaccinations, toxic habits, previous medications, exposure to social environments, and EuroQoL-5D (EQ-5D). Severe pneumonia with multilobar involvement and/or shock (SPAS) was the primary outcome of interest. We constructed two multivariate logistic regression models to explain the likelihood of developing SPAS and to create a clinical prediction rule for developing SPAS that includes clinically relevant variables. RESULTS: Laboratory-confirmed A(H1N1)pdm09, EQ-5D utility score 7 days before admission, more than one comorbidity, altered mental status, dyspnoea on arrival, days from onset of symptoms, and influenza season were associated with SPAS. In addition, not being vaccinated against seasonal influenza in the previous year, anaemia, altered mental status, fever and dyspnoea on arrival at hospital, difficulties in performing activities of daily living in the previous 7 days, and days from onset of symptoms to arrival at hospital were related to the likelihood of SPAS (area under the curve value of 0.75; Hosmer-Lemeshow p value of 0.84). CONCLUSIONS: These variables should be taken into account by physicians evaluating a patient affected by influenza as additional information to that provided by the usual risk scores.

Influenza vaccine effectiveness in preventing outpatient, inpatient, and severe cases of laboratory-confirmed influenza.

BACKGROUND: In most seasons, the influenza vaccine is effective in preventing influenza, but it is not clear whether it is equally effective in preventing mild and severe cases. We designed a case-control study to compare the effectiveness of the influenza vaccine in preventing outpatient, inpatient, and severe or fatal cases of laboratory-confirmed influenza. METHODS: Hospitalized patients (n = 691) with laboratory-confirmed influenza in the 2010-2011 season recruited in 29 Spanish hospitals were individually matched by age, admission/visit date, and province with an outpatient with laboratory-confirmed influenza and an outpatient control. Severe cases were considered those patients admitted to intensive care units or who died in the hospital (n = 177). We compared the influenza vaccine status of controls and outpatient cases, inpatient cases, and severe cases using conditional logistic regression adjusted for potential confounding factors. Severe and nonsevere inpatient influenza cases were compared using unconditional logistic regression. Vaccine effectiveness was (1 - odds ratio) × 100. RESULTS: Vaccine effectiveness was 75% (adjusted odds ratio [AOR], 0.25; 95% confidence interval [CI], .16-.39) in preventing influenza outpatient cases, 60% (AOR, 0.40; 95% CI, .25-.63) in preventing influenza-associated hospitalizations, and 89% (AOR, 0.11; 95% CI, .04-.37) in preventing severe cases. In inpatients, influenza vaccination was associated with a lower risk of severe influenza (AOR, 0.42; 95% CI, .22-.80). CONCLUSIONS: Influenza vaccination prevented influenza cases and hospitalizations and was associated with a better prognosis in inpatients with influenza. The combined effect of these 2 mechanisms would explain the high effectiveness of the vaccine in preventing severe cases due to influenza.

Trends in influenza vaccine coverage among primary healthcare workers in Spain, 2008-2011.

OBJECTIVE: To evaluate trends in seasonal influenza vaccination coverage in primary healthcare workers (PHCWs) in Spain between 2008 and 2011. METHODS: We made an anonymous web survey of PHCWs in 2012. Information on attitudes towards and knowledge of influenza vaccine, and immunization in previous seasons was collected. Self-reported vaccination coverage and factors related to vaccination continuity were analysed. RESULTS: Of 5433 workers contacted, 2625 (48.3%) responded to the survey: 47.0% were general practitioners, 10.3% paediatricians and 42.7% nurses. Their reported vaccination rates from seasons 2008-2009 to 2011-2012 decreased over time: 58.4%, 57.4%, 53.2% and 49.3% (linear trend, p < 0.001). Among workers vaccinated in any previous season, 70.2% were vaccinated again in 2011-2012, compared with 5.2% among those not previously vaccinated (p < 0.001). Continuity of vaccination increased with age and with the worker or cohabitant having a major chronic condition. Vaccination was higher in workers who recognized vaccination as effective and those worried about being infected or infecting patients. CONCLUSION: Influenza vaccination coverage in PHCWs has declined, especially after the pandemic. Intensive interventions are needed to change this trend. Knowledge of vaccination should be reinforced by stressing the effectiveness of the vaccine and the risks of influenza for workers and patients.

Social factors related to the clinical severity of influenza cases in Spain during the A (H1N1) 2009 virus pandemic.

BACKGROUND: During the 2009 influenza pandemic, a change in the type of patients most often affected by influenza was observed. The objective of this study was to assess the role of individual and social determinants in hospitalizations due to influenza A (H1N1) 2009 infection. METHODS: We studied hospitalized patients (cases) and outpatients (controls) with confirmed influenza A (H1N1) 2009 infection. A standardized questionnaire was used to collect data. Variables that might be related to the hospitalization of influenza cases were compared by estimation of the odds ratio (OR) and 95% confidence intervals (CI) and the variables entered into binomial logistic regression models. RESULTS: Hospitalization due to pandemic A (H1N1) 2009 influenza virus infections was associated with non-Caucasian ethnicity (OR: 2.18, 95% CI 1.17 - 4.08), overcrowding (OR: 2.84, 95% CI 1.20 - 6.72), comorbidity and the lack of previous preventive information (OR: 2.69, 95% CI: 1.50 - 4.83). Secondary or higher education was associated with a lower risk of hospitalization (OR 0.56, 95% CI: 0.36 - 0.87) CONCLUSIONS: In addition to individual factors such as comorbidity, other factors such as educational level, ethnicity or overcrowding were associated with hospitalization due to A (H1N1) 2009 influenza virus infections.

Lead, mercury and cadmium in umbilical cord blood and its association with parental epidemiological variables and birth factors.

BACKGROUND: In Spain, few studies have evaluated prenatal exposure to heavy metals. The objective of this study was to describe lead, mercury and cadmium concentrations in blood from a sample of newborn-mother-father trios, as well as to investigate the association between metals in cord blood and parental variables. We also explored the relationship between cord blood metal concentrations and child characteristics at birth. METHODS: Metal correlations among family members were assessed using Spearman Rank Correlation Coefficient. Linear regression was used to explore the association between parental variables and log-transformed cord blood lead and cord blood mercury concentrations. In the case of cadmium, tobit regression was used due to the existence of samples below the detection limit. The association between cord blood metal concentrations and child characteristics at birth was evaluated using linear regression. RESULTS: Geometric means for lead, mercury and cadmium were 14.09 µg/L, 6.72 µg/L and 0.27 µg/L in newborns; 19.80 µg/L, 3.90 µg/L and 0.53 µg/L in pregnant women; and 33.00 µg/L, 5.38 µg/L and 0.49 µg/L in men. Positive correlations were found between metal concentrations among members of the trio. Lead and cadmium concentrations were 15% and 22% higher in newborns from mothers who smoked during pregnancy, while mercury concentrations were 25% higher in newborns from mothers with greater fish intake. Cord-blood lead levels showed seasonal periodicity, with lower concentrations observed in winter. Cord blood cadmium concentrations over 0.29 µg/L were associated with lower 1-minute and 5-minute Apgar scores. CONCLUSIONS: These results reinforce the need to establish biomonitoring programs in Spain, and provide support for tobacco smoke and fish consumption as important preventable sources of heavy metal exposure in newborns. Additionally, our findings support the hypothesis that cadmium exposure might be deleterious to fetal development.