Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-5 (of 5 Records) |
Query Trace: Walter ND[original query] |
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Transnational Record Linkage for Tuberculosis Surveillance and Program Evaluation.
Aiona K , Lowenthal P , Painter JA , Reves R , Flood J , Parker M , Fu Y , Wall K , Walter ND . Public Health Rep 2015 130 (5) 475-84 OBJECTIVE: Pre-immigration tuberculosis (TB) screening, followed by post-arrival rescreening during the first year, is critical to reducing TB among foreign-born people in the United States. However, existing U.S. public health surveillance is inadequate to monitor TB among immigrants during subsequent years. We developed and tested a novel method for ascertaining post-U.S.-arrival TB outcomes among high-TB-risk immigrant cohorts to improve surveillance. METHODS: We used a probabilistic record linkage program to link pre-immigration screening records from U.S.-bound immigrants from the Philippines (n=422,593) and Vietnam (n=214,401) with the California TB registry during 2000-2010. We estimated sensitivity using Monte Carlo simulations to account for uncertainty in key inputs. Specificity was evaluated by using a time-stratified approach, which defined false-positives as TB records linked to pre-immigration screening records dated after the person had arrived in the United States. RESULTS: TB was reported in 4,382 and 2,830 people born in the Philippines and Vietnam, respectively, in California during the study period. Of these TB cases, records for 973 and 452 cases of people born in the Philippines and Vietnam, respectively, were linked to pre-immigration screening records. Sensitivity and specificity of linkage were 89% (90% credible interval [CrI] 83, 97) and 100%, respectively, for the Philippines, and 90% (90% CrI 83, 98) and 99.9%, respectively, for Vietnam. CONCLUSION: Electronic linkage of pre-immigration screening records to a domestic TB registry was feasible, sensitive, and highly specific in two high-priority immigrant cohorts. Transnational record linkage can be used for program evaluation and routine monitoring of post-U.S.-arrival TB risk among immigrants, but requires interagency data sharing and collaboration. |
Persistent latent tuberculosis reactivation risk in United States immigrants
Walter ND , Painter J , Parker M , Lowenthal P , Flood J , Fu Y , Asis R , Reves R . Am J Respir Crit Care Med 2014 189 (1) 88-95 RATIONALE: Current guidelines limit latent tuberculosis infection (LTBI) evaluation to persons in the United States less than or equal to 5 years based on the assumption that high TB rates among recent entrants are attributable to high LTBI reactivation risk, which declines over time. We hypothesized that high postarrival TB rates may instead be caused by imported active TB. OBJECTIVES: Estimate reactivation and imported TB in an immigrant cohort. METHODS: We linked preimmigration records from a cohort of California-bound Filipino immigrants during 2001-2010 with subsequent TB reports. TB was likely LTBI reactivation if the immigrant had no evidence of active TB at preimmigration examination, likely imported if preimmigration radiograph was abnormal and TB was reported less than or equal to 6 months after arrival, and likely reactivation of inactive TB if radiograph was abnormal but TB was reported more than 6 months after arrival. MEASUREMENTS AND MAIN RESULTS: Among 123,114 immigrants, 793 TB cases were reported. Within 1 year of preimmigration examination, 85% of TB was imported; 6 and 9% were reactivation of LTBI and inactive TB, respectively. Conversely, during Years 2-9 after U.S. entry, 76 and 24% were reactivation of LTBI and inactive TB, respectively. The rate of LTBI reactivation (32 per 100,000) did not decline during Years 1-9. CONCLUSIONS: High postarrival TB rates were caused by detection of imported TB through active postarrival surveillance. Among immigrants without active TB at baseline, reported TB did not decline over 9 years, indicating sustained high risk of LTBI reactivation. Revised guidelines should support LTBI screening and treatment more than 5 years after U.S. arrival. |
Seasonality of tuberculosis in the United States, 1993-2008
Willis MD , Winston CA , Heilig CM , Cain KP , Walter ND , Mac Kenzie WR . Clin Infect Dis 2012 54 (11) 1553-60 BACKGROUND: Although seasonal variation in tuberculosis incidence has been described in several recent studies, the mechanism underlying this seasonality remains unknown. Seasonality of tuberculosis disease may indicate the presence of season-specific risk factors that could potentially be controlled if they were better understood. We conducted this study to determine whether tuberculosis is seasonal in the United States and to describe patterns of seasonality in specific populations. METHODS: We performed a time series decomposition analysis of tuberculosis cases reported to the Centers for Disease Control and Prevention from 1993 through 2008. Seasonal amplitude of tuberculosis disease (the difference between the months with the highest and lowest mean case counts), was calculated for the population as a whole and for populations with select demographic, clinical, and epidemiologic characteristics. RESULTS: A total of 243,432 laboratory-confirmed tuberculosis cases were reported over a period of 16 years. A mean of 21.4% more cases were diagnosed in March, the peak month, compared with November, the trough month. The magnitude of seasonality did not vary with latitude. The greatest seasonal amplitude was found among children aged <5 years and in cases associated with disease clusters. CONCLUSIONS: Tuberculosis is a seasonal disease in the United States, with a peak in spring and trough in late fall. The latitude independence of seasonality suggests that reduced winter sunlight exposure may not be a strong contributor to tuberculosis risk. Increased seasonality among young children and clustered cases suggests that disease that is the result of recent transmission is more influenced by season than disease resulting from activation of latent infection. |
Influenza circulation and the burden of invasive pneumococcal pneumonia during a non-pandemic period in the United States
Walter ND , Taylor TH , Shay DK , Thompson WW , Brammer L , Dowell SF , Moore MR . Clin Infect Dis 2010 50 (2) 175-83 BACKGROUND: Animal models and data from influenza pandemics suggest that influenza infection predisposes individuals to pneumococcal pneumonia. Influenza may contribute to high winter rates of pneumococcal pneumonia during non-pandemic periods, but the magnitude of this effect is unknown. With use of United States surveillance data during 1995-2006, we estimated the association between influenza circulation and invasive pneumococcal pneumonia rates. METHODS: Weekly invasive pneumococcal pneumonia incidence, defined by isolation of pneumococci from normally sterile sites in persons with clinical or radiographic pneumonia, was estimated from active population-based surveillance in 3 regions of the United States. We used influenza virus data collected by World Health Organization collaborating laboratories in the same 3 regions in seasonally adjusted negative binomial regression models to estimate the influenza-associated fraction of pneumococcal pneumonia. RESULTS: During approximately 185 million person-years of surveillance, we observed 21,239 episodes of invasive pneumococcal pneumonia; 485,691 specimens were tested for influenza. Influenza circulation was associated with 11%-14% of pneumococcal pneumonia during periods of influenza circulation and 5%-6% overall. In 2 of 3 regions, the association was strongest when influenza circulation data were lagged by 1 week. CONCLUSIONS: During recent seasonal influenza epidemics in the United States, a modest but potentially preventable fraction of invasive pneumococcal pneumonia was associated with influenza circulation. |
Holiday spikes in pneumococcal disease among older adults
Walter ND , Taylor TH Jr , Dowell SF , Mathis S , Moore MR , Active Bacterial Core Surveillance System Team . N Engl J Med 2009 361 (26) 2584-5 Rates of invasive pneumococcal disease in the United States increase dramatically, or “spike,” during winter holidays.1 We analyzed population-based surveillance data to determine whether spikes may be caused by increased transmission from children to older adults. | Pneumococci spread through upper respiratory secretions, especially those of young children.2 Certain serotypes disproportionately colonize young children.3 The introduction of the pediatric heptavalent pneumococcal conjugate vaccine (PCV7; Prevnar, Wyeth) in 2000 led to a decrease in invasive pneumococcal disease among vaccinated children and reduced transmission to unvaccinated persons.2,4 |
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