American journal of epidemiology
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In 1976, the national swine influenza vaccination program in the United States was suspended because of an increased risk of Guillain-Barré syndrome. Subsequent studies of seasonal influenza vaccine have given conflicting results. The authors used the self-controlled case series method to investigate the relation of Guillain-Barré syndrome with influenza vaccine and influenzalike illness using cases recorded in the General Practice Research Database from 1990 to 2005 in the United Kingdom. ⋯ The relative incidence was similar (0.89, 95% confidence interval: 0.42, 1.89) when the analysis was restricted to a subset of validated cases. The authors found no evidence of an increased risk of Guillain-Barré syndrome after seasonal influenza vaccine. The finding of a greatly increased risk after influenzalike illness is consistent with anecdotal reports of a preceding respiratory illness in Guillain-Barré syndrome and has important implications for the risk/benefit assessment that would be carried out should pandemic vaccines be deployed in the future.
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Many neural tube defects can be prevented if women take folic acid around the time of conception. However, the majority of women do not take folic acid at the critical time, so the US government required that food be fortified with folic acid effective January 1, 1998. Whether the amount being added was sufficient to prevent all folate-related neural tube defects has been hotly debated. ⋯ Its effect on cancer remains unclear. Folic acid may be useful in primary prevention but may also stimulate the growth of existing malignancies or premalignant lesions. Although these issues remain unresolved, Mosley et al. have provided important data to address the primary question: Does fortification prevent folate-related neural tube defects?
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Comparative Study
Geographic clustering of nonmedical exemptions to school immunization requirements and associations with geographic clustering of pertussis.
School immunization requirements are important in controlling vaccine-preventable diseases in the United States. Forty-eight states offer nonmedical exemptions to school immunization requirements. Children with exemptions are at increased risk of contracting and transmitting vaccine-preventable diseases. ⋯ The overlap of exemptions clusters and pertussis clusters remained significant after adjustment for population density, proportion of racial/ethnic minorities, proportion of children aged 5 years or younger, percentage of persons below the poverty level, and average family size (odds ratio = 2.7, 95% confidence interval: 2.2, 3.3). Geographic pockets of vaccine exemptors pose a risk to the whole community. In addition to monitoring state-level exemption rates, health authorities should be mindful of within-state heterogeneity.
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The authors evaluated the association between receipt of measles-mumps-rubella (MMR) vaccine and asthma-like disease in early childhood in a Danish nationwide cohort study (N = 871,234). Two outcomes were included: hospitalizations with asthma diagnoses and use of anti-asthma medications (for a subset of the cohort only). Poisson regression was used to estimate rate ratios according to vaccination status. ⋯ This "protective" effect of MMR vaccine was more pronounced for hospitalizations with severe asthma diagnoses (status asthmaticus: RR = 0.63, 95% CI: 0.49, 0.82) and use of medication that was highly specific for asthma (long-acting beta2-agonist inhalant: RR = 0.68, 95% CI: 0.63, 0.73). MMR vaccine was not negatively associated with anti-asthma medications often used for wheezing illnesses in early childhood (systemic beta2-agonist: RR = 1.02, 95% CI: 1.01, 1.02). These results are compatible not with an increased risk of asthma following MMR vaccination but rather with the hypothesis that MMR vaccination is associated with a reduced risk of asthma-like disease in young children.
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Injury is the leading cause of alcohol-attributable mortality in Canada. Risk is determined by amount consumed per occasion and accumulates across drinking episodes. The authors estimated alcohol-attributable injury mortality in Canada for 2002 by combining the absolute risk of injury unrelated to alcohol with relative risks that were specific to gender and consumption per occasion, while taking into account lifetime number of drinking occasions. ⋯ The probability of mortality was 1 in 100 for all levels of consumption above 3 drinks 3 times per week for men and above 5 drinks 3 times per week for women. No safe level of consumption is recommended based on these results, although risk is much lower for consuming 3 standard drinks or less fewer than 3 times per week. Absolute risk reflects long-term effects of drinking patterns and is important for risk-communication and alcohol-control policy.