WHAT'S KNOWN ON THIS SUBJECT: Previous studies have shown that nonmedical exemptions (NMEs) to immunization cluster geographically and contribute to outbreaks of vaccinepreventable diseases such as pertussis. The 2010 pertussis resurgence in California has been widely attributed to waning immunity from acellular pertussis vaccines.
WHAT THIS STUDY ADDS:This study provides evidence of spatial and temporal clustering of NMEs and clustering of pertussis cases and suggests that geographic areas with high NME rates were also associated with high rates of pertussis in California in 2010.abstract BACKGROUND: In 2010, 9120 cases of pertussis were reported in California, more than any year since 1947. Although this resurgence has been widely attributed to waning immunity of the acellular vaccine, the role of vaccine refusal has not been explored in the published literature. Many factors likely contributed to the outbreak, including the cyclical nature of pertussis, improved diagnosis, and waning immunity; however, it is important to understand if clustering of unvaccinated individuals also played a role.
METHODS:We analyzed nonmedical exemptions (NMEs) for children entering kindergarten from 2005 through 2010 and pertussis cases with onset in 2010 in California to determine if NMEs increased in that period, if children obtaining NMEs clustered spatially, if pertussis cases clustered spatially and temporally, and if there was statistically significant overlap between clusters of NMEs and cases.RESULTS: Kulldorff' s scan statistics identified 39 statistically significant clusters of high NME rates and 2 statistically significant clusters of pertussis cases in this time period. Census tracts within an exemptions cluster were 2.5 times more likely to be in a pertussis cluster (odds ratio = 2.47, 95% confidence interval: 2.22-2.75). More cases occurred within as compared with outside exemptions clusters (incident rate ratios = 1.20, 95% confidence interval: 1.10-1.30). The association remained significant after adjustment for demographic factors. NMEs clustered spatially and were associated with clusters of pertussis cases.
CONCLUSIONS:
Abstract. Hepatitis E virus (HEV) infections lead to tens of thousands of deaths annually, mostly in developing countries. Hepatitis E poses a significant threat to the health of expectant mothers, a well-noted epidemiologic feature of the disease, but the contribution of vertically transmitted HEV infection to fetal and neonatal morbidity and mortality has received limited attention. Evidence assembled to date suggests that mother-to-child HEV transmission may be frequent and deleterious to the fetus and newborn in pregnancies affected by hepatitis E. Additional work is required to resolve key questions. (1) What risks do subclinical maternal HEV infections and infections early in pregnancy pose to fetal health and development? (2) Does vertical transmission occur during labor and/or breastfeeding and contribute appreciably to neonatal morbidity and mortality? (3) How do treatment decisions for severely ill mothers affect fetal and neonatal outcomes? (4) Can maternal vaccination effectively prevent vertical transmission of HEV?
Impaired RSV antibody transport was observed in approximately one-third of maternal/cord pairs. Hypergammaglobulinemia, but not PM, was associated with impaired transport, particularly among women with low RSV PRNT. Detection of RSV PRNT <1:200 in one-third of cord sera confirms the need to increase levels of RSV neutralizing antibody in pregnant women through maternal immunization.
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