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Large outbreaks, such as those caused by influenza, put a strain on resources necessary for their control. In particular, children have been shown to play a key role in influenza transmission during recent outbreaks, and targeted interventions, such as school closures, could positively impact the course of emerging epidemics. As an outbreak is unfolding, it is important to be able to estimate reproductive numbers that incorporate this heterogeneity and to use surveillance data that is routinely collected to more effectively target interventions and obtain an accurate understanding of transmission dynamics. There are a growing number of methods that estimate age-group specific reproductive numbers with limited data that build on methods assuming a homogenously mixing population. In this article, we introduce a new approach that is flexible and improves on many aspects of existing methods. We apply this method to influenza data from two outbreaks, the 2009 H1N1 outbreaks in South Africa and Japan, to estimate age-group specific reproductive numbers and compare it to three other methods that also use existing data from social mixing surveys to quantify contact rates among different age groups. In this exercise, all estimates of the reproductive numbers for children exceeded the critical threshold of one and in most cases exceeded those of adults. We introduce a flexible new method to estimate reproductive numbers that describe heterogeneity in the population. [ABSTRACT FROM AUTHOR]

Background. Xpert MTB/RIF (Xpert) detects rifampicin-resistant tuberculosis (RR-tuberculosis), enabling physicians to rapidly initiate a World Health Organization-recommended 5-drug regimen while awaiting second-line drug-susceptibility test (DST) results. We quantified the second-line DST results time and proportion of patients potentially placed on suboptimal therapy. Methods. We included RR-tuberculosis patients detected using Xpert at the South African National Health Laboratory Services (NHLS) of the Western Cape between November 2011 and June 2013 and at Eastern Cape, Free State, and Gauteng NHLS between November 2012 and December 2013. We calculated time from specimen collection to phenotypic second-line DST results. We identified isoniazid and ethionamide resistance mutations on line probe assay and performed pyrazinamide sequencing. Results. Among 1332 RR-tuberculosis patients, only 44.7% (596) had second-line DST for both fluoroquinolones and second-line injectable: 55.8% (466 of 835) in the Western Cape and 26.2% (130 of 497) in the other provinces. Patients with smear negative disease and age ≤10 years were less likely to have a result (risk ratio [RR] = 0.72; 95% CI, 0.64-0.81 and RR = 0.49; 95% CI, 0.26-0.79). Median time to second-line DST was 53 days (range, 8-259). Of the 252 patients with complete second-line DST, 101 (40.1%) potentially initiated a suboptimal regimen: 46.8% in the Western Cape and 25.3% in the other provinces. Conclusions. Many South Africans diagnosed with RR-tuberculosis by Xpert initiate a suboptimal regimen, with information to adjust therapy available in half of all patients after a median 7 weeks. Algorithm completion and time delays remain challenging. [ABSTRACT FROM AUTHOR]

BACKGROUND Evidence shows that exposure to air pollutants can increase blood pressure in the short and long term. Some studies show higher levels of hypertension prevalence in areas of high pollution. Few data exist on the association of air pollution with hypertension incidence. The purpose of the present study was to prospectively assess the associations of the traffic-related nitrogen dioxide (NO2) and of ozone with the incidence of hypertension in the Black Women's Health Study (BWHS), a large cohort study of African American women. METHODS We used Cox proportional hazards models to calculate hazard ratios (HRs) and 95% confidence intervals (CI) for hypertension associated with exposure to NO2 and ozone among 33,771 BWHS participants. NO2 and ozone levels at participant residential locations were estimated with validated models. RESULTS From 1995 to 2011, 9,570 incident cases of hypertension occurred in a total of 348,154 person-years (median follow-up time, 11 years). The multivariable HRs per interquartile range of NO2 (9.7 ppb) and ozone (6.7 ppb) were 0.92 (95% CI = 0.86, 0.98) and 1.09 (95% CI = 1.00, 1.18). CONCLUSIONS In this large cohort of African American women, higher ozone levels were associated with an increase in hypertension incidence. Higher NO2 levels were not associated with greater hypertension incidence; indeed, incidence was lower at higher NO2 levels. [ABSTRACT FROM AUTHOR]

Background. Tuberculosis disease develops in only 5%-10% of humans infected with Mycobacterium tuberculosis . The mechanisms underlying this variability remain poorly understood.We recently demonstrated that colony-forming units of M. tuberculosis in cough-generated aerosols are a better predictor of infection than the standard sputum acid-fast bacilli smear.We hypothesized that cough aerosol cultures may also predict progression to tuberculosis disease in contacts. Methods. We conducted a retrospective cohort study of 85 patients with smear-positive tuberculosis and their 369 household contacts in Kampala, Uganda. Index case patients underwent a standard evaluation, and we cultured M. tuberculosis from cough aerosols. Contacts underwent a standard evaluation at enrollment, and they were later traced to determine their tuberculosis status. Results. During a median follow-up of 3.9 years, 8 (2%) of the contacts developed tuberculosis disease. In unadjusted and adjusted analyses, incident tuberculosis disease in contacts was associated with sputum Mycobacterial Growth Indicator Tube culture (odds ratio, 8.2; 95% confidence interval, 1.1-59.2; P = .04), exposure to a high-aerosol tuberculosis case patient (6.0, 1.4-25.2; P = .01), and marginally, human immunodeficiency virus in the contact (6.11; 0.89-41.7; P = .07). We present data demonstrating that sputum and aerosol specimens measure 2 related but different phenomena. Conclusions. We found an increased risk of tuberculosis progression among contacts of high-aerosol case patients. The hypothesis that a larger infectious inoculum, represented by high aerosol production, determines the risk of disease progression deserves evaluation in future prospective studies. [ABSTRACT FROM AUTHOR]

Background: Clinical studies have shown that exposure to fine particulate matter (PM2.5) can increase insulin resistance and blood pressure. The epidemiologic evidence for an association of PM2.5 exposure with the incidence of type 2 diabetes or hypertension is inconsistent. Even a modest association would have great public health importance given the ubiquity of exposure and high prevalence of the conditions.Methods: We used Cox proportional hazards models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for incident type 2 diabetes and hypertension associated with exposure to PM2.5 in a large cohort of African American women living in 56 metropolitan areas across the US, using data from the Black Women's Health Study. Pollutant levels were estimated at all residential locations over follow-up with a hybrid model incorporating land use regression and Bayesian Maximum Entropy techniques.Results: During 1995 to 2011, 4,387 cases of diabetes and 9,570 cases of hypertension occurred. In models controlling for age, questionnaire cycle, and metro area, there were positive associations with diabetes (HR = 1.13, 95% CI = 1.04, 1.24) and hypertension (HR = 1.06, 95% CI = 1.00, 1.12) per interquartile range of PM2.5 (2.9 μg/m). Multivariable HRs, however, were 0.99 (95% CI = 0.90, 1.09) for diabetes and 0.99 (95% CI = 0.93, 1.06) for hypertension.Conclusions: Our results provide little support for an association of PM2.5 with diabetes or hypertension incidence. [ABSTRACT FROM AUTHOR]

(B-C) The case reproductive number is defined as the average number of new infections that an individual who becomes infected on day ti (green arrows in B) or symptomatic on day ts (yellow arrows in C) will eventually go on to cause (blue downward arrows in B and C). There is an error in the caption for Fig 1, "Instantaneous reproductive number as estimated by the method of Cori et al. vs. cohort reproductive number estimated by Wallinga and Teunis" sentence four. [Extracted from the article]

We examined hepatitis C virus screening among HIV-infected patients enrolled in care at 7 US sites between 2000 and 2011. While there is a trend toward more frequent screening over time, it remains variable among sites and high-risk MSM are screened infrequently.Background. Human immunodeficiency virus (HIV)-infected, hepatitis C virus (HCV)-uninfected patients are at risk for incident HCV infection, but little is known about screening practices for incident HCV among HIV-infected individuals in HIV primary care clinics.Methods. We used data from the Center for AIDS Research Network of Integrated Clinical Systems (CNICS) to investigate historical trends in screening for incident HCV infection among HIV-infected patients who were HCV-uninfected at enrollment in care. We used descriptive measures and Poisson regression to identify factors associated with screening for HCV infection (using HCV antibody or RNA), performed temporal analyses to assess changes in screening over time, and investigated the frequency with which elevated alanine aminotransferase (ALT) levels were followed by diagnostic HCV testing.Results. Among 17 090 patients registered at CNICS sites between 2000 and 2011, 14 534 (85%) received HCV antibody screening within 3 months of enrolling in care, and 9077 met all of the inclusion criteria. Only 55.6% ever received additional HCV screening. HCV screening increased over time, but not uniformly at all sites. Only 26.7% of first-time ALT elevations to >100 IU/L were followed up within 12 months by HCV antibody or RNA testing.Conclusions. Although most HIV-infected patients were screened for prevalent HCV infection at enrollment in care, only half who were HCV uninfected were screened again. Screening varied between sites, even when controlling for demographics and risk behaviors. Patients with new ALT elevations to >100 IU/L were seldom assessed for incident HCV infection. Guidelines are needed to help HIV providers know whom to screen, how frequently to screen, and which screening test to use. [ABSTRACT FROM AUTHOR]

Background. On July 12, 2010, Boston Medical Center (BMC), the busiest emergency department (ED) in Massachusetts, with more than 100,000 adult patient visits per year, consolidated its two fully functional EDs into one. In preparation for this consolidation, BMC implemented systems changes to mitigate potential negative effects on both BMC and emergency medical services (EMS) providers, including Boston Emergency Medical Services (Boston EMS), the provider of 9-1-1 EMS to the City of Boston. Objective. To examine the impact of the closure of an ED on an urban EMS system in a setting where ambulance diversion is not allowed. Methods. We performed a before-and-after study that examined the effects of an ED closure on BMC and Boston EMS. We examined ED and Boston EMS volumes and ambulance turnaround intervals from June 1, 2010, to July 11, 2010 (preclosure) as compared with July 12, 2010, to August 26, 2010 (postclosure). Mean ED and Boston EMS volumes and Boston EMS turnaround intervals were calculated in four-hour shifts. We used multivariate analysis to analyze electronic medical systems data from BMC and Boston EMS and linear regression. We used autoregressive integrated moving average (ARIMA) models to determine the effect of the ED closure on turnaround intervals, ED volumes, and transport volumes. All analyses were adjusted for shift, ED volume, day of the week, and citywide EMS transport volumes. Results. After ED closure, there was a statistically significant increase of 0.89 minutes (p == 0.02) in the mean EMS turnaround intervals. Additionally, the total ED volume decreased by 3.67 visits per shift (p < 0.001). The ratio of patients transported by Boston EMS to BMC remained unchanged (p == 0.11) for two weeks before and two weeks after the closure. Conclusions. The closure of one ED resulted in a statistically significant increase in turnaround intervals and a significant decrease in ED volume independent of EMS volumes. In the absence of ambulance diversion, ratios of EMS turnaround intervals and EMS volumes according to hospital destination can be used as alternatives to ambulance diversion times to examine the effects of system-level changes such as closure of an ED on an urban EMS system. Key words: emergency department; EMS system; closure; impact; consolidation [ABSTRACT FROM AUTHOR]