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Background: Infants are at high risk for influenza illness, but are ineligible for vaccination before 6 months. Transfer of maternal antibodies to the fetus has been demonstrated for 2009 A/H1N1 pandemic vaccines; however, clinical effectiveness is unknown. Our objective was to evaluate the association between 2009 A/H1N1 pandemic vaccination during pregnancy and rates of infant influenza and pneumonia. Methods: We linked a population-based birth cohort to administrative databases to measure rates of influenza and pneumonia diagnosed during ambulatory physician visits, hospitalizations and emergency department visits during one year of follow-up. We estimated incidence rate ratios and 95% confidence intervals (95% CI) using Poisson regression, comparing infants born to A/H1N1-vaccinated women (vaccine-exposed infants) with unexposed infants, adjusted for confounding using high-dimensional propensity scores. Results: Among 117,335 infants in the study, 36,033 (31%) were born to A/H1N1-vaccinated women. Crude rates of influenza during the pandemic (per 100,000 infant-days) for vaccine-exposed and unexposed infants were similar (2.19, 95% CI: 1.27–3.76 and 3.60, 95% CI: 2.51–5.14, respectively), as were crude rates of influenza and pneumonia combined. We did not observe any significant differences in rates of study outcomes between study groups during the second wave of the 2009 A/H1N1 pandemic, nor during any post-pandemic time period. Conclusion: We observed no difference in rates of study outcomes among infants born to A/H1N1-vaccinated mothers relative to unexposed infants born during the second A/H1N1 pandemic wave; however, due to late availability of the pandemic vaccine, the available follow-up time during the pandemic time period was very limited. [ABSTRACT FROM AUTHOR]

It is unclear whether seasonal influenza vaccination results in a net increase or decrease in the risk for Guillain-Barré syndrome (GBS). To assess the effect of seasonal influenza vaccination on the absolute risk of acquiring GBS, we used simulation models and published estimates of age- and sex-specific risks for GBS, influenza incidence, and vaccine effectiveness. For a hypothetical 45-year-old woman and 75-year-old man, excess GBS risk for influenza vaccination versus no vaccination was -0.36/1 million vaccinations (95% credible interval -1.22% to 0.28) and -0.42/1 million vaccinations (95% credible interval, -3.68 to 2.44), respectively. These numbers represent a small absolute reduction in GBS risk with vaccination. Under typical conditions (e.g. influenza incidence rates >5% and vaccine effectiveness >60%), vaccination reduced GBS risk. These findings should strengthen confidence in the safety of influenza vaccine and allow health professionals to better put GBS risk in context when discussing influenza vaccination with patients. [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted in an effort to compare apolipoproteins and cholesterol as indices for risk of acute myocardial infarction. Researchers conducted a standardised case control study of acute myocardial infarction in 12,461 cases and 14,637 age matched and sex matched controls in 52 countries. They found that the non-fasting ApoB/ApoA1 ratio was superior to any of the cholesterol ratios for estimation of the risk of myocardial infarction in all ethnic groups, in both sexes, and at all ages, and that it should be introduced into worldwide clinical practice.

Summary Background Tobacco use is one of the major avoidable causes of cardiovascular diseases. We aimed to assess the risks associated with tobacco use (both smoking and non-smoking) and second hand tobacco smoke (SHS) worldwide. Methods We did a standardised case-control study of acute myocardial infarction (AMI) with 27 089 participants in 52 countries (12 461 cases, 14 637 controls). We assessed relation between risk of AMI and current or former smoking, type of tobacco, amount smoked, effect of smokeless tobacco, and exposure to SHS. We controlled for confounders such as differences in lifestyles between smokers and non-smokers. Findings Current smoking was associated with a greater risk of non-fatal AMI (odds ratio [OR] 2·95, 95% CI 2·77-3·14, p<0·0001) compared with never smoking; risk increased by 5·6% for every additional cigarette smoked. The OR associated with former smoking fell to 1·87 (95% CI 1·55-2·24) within 3 years of quitting. A residual excess risk remained 20 or more years after quitting (1·22, 1·09-1·37). Exclusion of individuals exposed to SHS in the never smoker reference group raised the risk in former smokers by about 10%. Smoking beedies alone (indigenous to South Asia) was associated with increased risk (2·89, 2·11-3·96) similar to that associated with cigarette smoking. Chewing tobacco alone was associated with OR 2·23 (1·41-3·52), and smokers who also chewed tobacco had the highest increase in risk (4·09, 2·98-5·61). SHS was associated with a graded increase in risk related to exposure; OR was 1·24 (1·17-1·32) in individuals who were least exposed (1-7 h per week) and 1·62 (1·45-1·81) in people who were most exposed (>21 h per week). Young male current smokers had the highest population attributable risk (58·3%; 95% CI 55·0-61·6) and older women the lowest (6·2%, 4·1-9·2). Population attributable risk for exposure to SHS for more than 1 h per week in never smokers was 15·4% (12·1-19·3). Conclusion Tobacco use is one of the most important causes of AMI globally, especially in men. All forms of tobacco use, including different types of smoking and chewing tobacco and inhalation of SHS, should be discouraged to prevent cardiovascular diseases. [ABSTRACT FROM AUTHOR]

Summary: Background: The possible risk of Guillain-Barré syndrome from influenza vaccines remains a potential obstacle to achieving high vaccination coverage. However, influenza infection might also be associated with Guillain-Barré syndrome. We aimed to assess the risk of Guillain-Barré syndrome after seasonal influenza vaccination and after influenza-coded health-care encounters. Methods: We used the self-controlled risk interval design and linked universal health-care system databases from Ontario, Canada, with data obtained between 1993 and 2011. We used physician billing claims for influenza vaccination and influenza-coded health-care encounters to ascertain exposures. Using fixed-effects conditional Poisson regression, we estimated the relative incidence of hospitalisation for primary-coded Guillain-Barré syndrome during the risk interval compared with the control interval. Findings: We identified 2831 incident admissions for Guillain-Barré syndrome; 330 received an influenza vaccine and 109 had an influenza-coded health-care encounter within 42 weeks before hospitalisation. The risk of Guillain-Barré syndrome within 6 weeks of vaccination was 52% higher than in the control interval of 9–42 weeks (relative incidence 1·52; 95% CI 1·17–1·99), with the greatest risk during weeks 2–4 after vaccination. The risk of Guillain-Barré syndrome within 6 weeks of an influenza-coded health-care encounter was greater than for vaccination (15·81; 10·28–24·32). The attributable risks were 1·03 Guillain-Barré syndrome admissions per million vaccinations, compared with 17·2 Guillain-Barré syndrome admissions per million influenza-coded health-care encounters. Interpretation: The relative and attributable risks of Guillain-Barré syndrome after seasonal influenza vaccination are lower than those after influenza illness. Patients considering immunisation should be fully informed of the risks of Guillain-Barré syndrome from both influenza vaccines and influenza illness. Funding: Canadian Institutes of Health Research. [ABSTRACT FROM AUTHOR]