The National Center for Health Statistics (NCHS) disseminates information on a broad range of health topics through diverse publications. These publications must rely on clear and transparent presentation standards that can be broadly and efficiently applied. Standards are particularly important for large, cross-cutting reports where estimates cannot be individually evaluated and indicators of precision cannot be included alongside the estimates. This report describes the NCHS Data Presentation Standards for Proportions. The multistep NCHS Data Presentation Standards for Proportions are based on a minimum denominator sample size and on the absolute and relative widths of a confidence interval calculated using the Clopper-Pearson method. Proportions (usually multiplied by 100 and expressed as percentages) are the most commonly reported estimates in NCHS reports.

OBJECTIVES: Free thyroxine (FT4) in serum is routinely measured in clinical practice to diagnose and monitor thyroid disease. Due to its concentration in picomolar range and the delicate equilibrium of free and protein-bound T4, accurate measurement is challenging. As a consequence, large inter-method differences in FT4 results exists. Optimal method design and standardization of the FT4 measurement is therefore necessary. The IFCC Working Group for Standardization of Thyroid Function Tests proposed a reference system with a conventional reference measurement procedure (cRMP) for FT4 in serum. In this study, we describe our FT4 candidate cRMP and its validation in clinical samples. METHODS: This candidate cRMP is based on equilibrium dialysis (ED) combined with determination of T4 with an isotope-dilution liquid chromatography tandem mass-spectrometry (ID-LC-MS/MS) procedure and was developed according to the endorsed conventions. Its accuracy, reliability, and comparability was investigated using human sera. RESULTS: It was shown that the candidate cRMP adhered to the conventions and its accuracy, precision, and robustness were adequate in serum of healthy volunteers. CONCLUSIONS: Our candidate cRMP measures FT4 accurately and performs well in serum matrix.

BACKGROUND: Accurate and reliable measurement of human serum free thyroxine (FT4) is critical for the diagnosis and treatment of thyroid diseases. However, concerns have been raised regarding the performance of FT4 measurements in patient care. Centers for Disease Control and Prevention Clinical Standardization Programs (CDC-CSP) address these concerns by creating a FT4 standardization program to standardize FT4 measurements. The study aims to develop a highly accurate and precise candidate Reference Measurement Procedure (cRMP), as one key component of CDC-CSP, for standardization of FT4 measurements. METHODS: Serum FT4 was separated from protein-bound thyroxine with equilibrium dialysis (ED) following the recommended conditions in the Clinical and Laboratory Standards Institute C45-A guideline and the published RMP [23]. FT4 in dialysate was directly quantified with liquid chromatography-tandem mass spectrometry (LC-MS/MS) without derivatization. Gravimetric measurements of specimens and calibrator solutions, calibrator bracketing, isotope dilution, enhanced chromatographic resolution, and T4 specific mass transitions were used to ensure the accuracy, precision, and specificity of the cRMP. RESULTS: The described cRMP agreed well with the established RMP and two other cRMPs in an interlaboratory comparison study. The mean biases of each method to the overall laboratory mean were within ±2.5%. The intra-day, inter-day, and total imprecision for the cRMP were within 4.4%. The limit of detection was 0.90 pmol/L, which was sufficiently sensitive to determine FT4 for patients with hypothyroidism. The structural analogs of T4 and endogenous components in dialysate did not interfere with the measurements. CONCLUSION: Our ED-LC-MS/MS cRMP provides high accuracy, precision, specificity, and sensitivity for FT4 measurement. The cRMP can serve as a higher-order standard for establishing measurement traceability and provide an accuracy base for the standardization of FT4 assays.

After the emergence of SARS-CoV-2 in late 2019, transmission expanded globally, and on January 30, 2020, COVID-19 was declared a public health emergency of international concern.* Analysis of the early Wuhan, China outbreak (1), subsequently confirmed by multiple other studies (2,3), found that 80% of deaths occurred among persons aged ≥60 years. In anticipation of the time needed for the global vaccine supply to meet all needs, the World Health Organization (WHO) published the Strategic Advisory Group of Experts on Immunization (SAGE) Values Framework and a roadmap for prioritizing use of COVID-19 vaccines in late 2020 (4,5), followed by a strategy brief to outline urgent actions in October 2021.(†) WHO described the general principles, objectives, and priorities needed to support country planning of vaccine rollout to minimize severe disease and death. A July 2022 update to the strategy brief(§) prioritized vaccination of populations at increased risk, including older adults,(¶) with the goal of 100% coverage with a complete COVID-19 vaccination series** for at-risk populations. Using available public data on COVID-19 mortality (reported deaths and model estimates) for 2020 and 2021 and the most recent reported COVID-19 vaccination coverage data from WHO, investigators performed descriptive analyses to examine age-specific mortality and global vaccination rollout among older adults (as defined by each country), stratified by country World Bank income status. Data quality and COVID-19 death reporting frequency varied by data source; however, persons aged ≥60 years accounted for >80% of the overall COVID-19 mortality across all income groups, with upper- and lower-middle-income countries accounting for 80% of the overall estimated excess mortality. Effective COVID-19 vaccines were authorized for use in December 2020, with global supply scaled up sufficiently to meet country needs by late 2021 (6). COVID-19 vaccines are safe and highly effective in reducing severe COVID-19, hospitalizations, and mortality (7,8); nevertheless, country-reported median completed primary series coverage among adults aged ≥60 years only reached 76% by the end of 2022, substantially below the WHO goal, especially in middle- and low-income countries. Increased efforts are needed to increase primary series and booster dose coverage among all older adults as recommended by WHO and national health authorities.

Measurements of thyroid stimulating hormone (TSH) and free thyroxine (fT4) are critical for the early detection of thyroid diseases and for monitoring treatment. The IFCC Committee for Standardization of Thyroid Function Tests (C-STFT) established reference systems for TSH harmonization and FT4 standardization, and is now working national partners on implementing these reference systems. These implementation activities include the maintenance of the reference systems, their use to standardize and harmonize assays, and educational activities to inform stakeholders about anticipated changes in measurement values as a result of standardization and harmonization. The IFCC C-STFT formed a network of reference laboratories for FT4 and is creating a new harmonization panel for TSH. The U.S. Centers for Disease Control and Prevention is a member of the reference laboratory network and is launching a formal standardization program for FT4. In Japan, national organizations successfully implemented TSH harmonization and established harmonized reference intervals for TSH. The C-STFT made available on its website research findings about potential concerns, communication needs and benefits of FT4 standardization and is assisting local organizations with communicating changes related to these standardization and harmonization efforts. Implementation of fT4 standardization and TSH harmonization is a complex, continuous task that requires collaboration with IVD manufacturers, laboratories, physicians and health care providers. C-STFT is working successfully with national organizations and local groups on improving FT4 and TSH measurements.

The last poliomyelitis cases reported in Papua New Guinea occurred in 1996. Papua New Guinea is one of 37 countries (or areas) of the World Health Organization Western Pacific Region that were certified free of indigenous wild poliovirus in 2000. On June 22, 2018, the National Department of Health confirmed an outbreak of poliomyelitis caused by circulating vaccine-derived poliovirus type 1 (cVDPV1) following isolation of genetically linked virus from a patient with paralysis and nonhousehold community contacts. The index patient was a boy aged 6 years from Lae, Morobe Province, with onset of paralysis on April 25 and history of having received 2 doses of Sabin oral poliovirus vaccine (OPV).* Genetic characterization of the isolate identified 14 nucleotide differences from the Sabin 1 strain in the VP1 coding region, suggesting circulation for >1 year. As of February 4, 2019, a total of 26 confirmed cases had been identified in nine of 22 provinces, including 19 in children aged <5 years, six in patients aged 5–14 years, and one in a patient aged 17 years. The most recent case onset was October 18, 2018 (Figure). Eighteen (69%) cases were linked to areas with large transient populations, including those near mines or plantations.

BACKGROUND: Biomarkers of tobacco exposure have a central role in studies of tobacco use and nicotine intake. The most significant exposure markers are nicotine itself and its metabolites in urine. Therefore, it is important to evaluate the performance of laboratories conducting these biomarker measurements. METHODS: This report presents the results from a method performance study involving 11 laboratories from 6 countries which are currently active in this area. Each laboratory assayed blind replicates of 7 human urine pools at various concentrations on 3 separate days. The samples included 5 pools blended from smoker and nonsmoker urine sources, and 2 additional blank urine samples fortified with pure nicotine, cotinine and hydroxycotinine standards. All laboratories used their own methods, and all were based on some form of liquid chromatography / tandem mass spectrometry. RESULTS: Overall, good agreement was found among the laboratories in this study. Intralaboratory precision was good, and in the fortified pools the mean bias observed was &lt; + 3.5% for nicotine, approximately 1.2% for hydroxycotinine, and less than 1% for cotinine (1 outlier excluded in each case). Both indirect and direct methods for analyzing the glucuronides gave comparable results. CONCLUSIONS: This evaluation indicates that the experienced laboratories participating in this study can produce reliable and comparable human urinary nicotine metabolic profiles in samples from people with significant recent exposure to nicotine. IMPACT: This work supports the reliability and agreement of an international group of established laboratories measuring nicotine and its metabolites in urine in support of nicotine exposure studies.

This Practical Guidance for Clinical Microbiology document on the laboratory diagnosis of parasites from the gastrointestinal tract provides practical information for the recovery and identification of relevant human parasites. The document is based on a comprehensive literature review and expert consensus on relevant diagnostic methods. However, it does not include didactic information on human parasite life cycles, organism morphology, clinical disease, pathogenesis, treatment, or epidemiology and prevention. As greater emphasis is placed on neglected tropical diseases, it becomes highly probable that patients with gastrointestinal parasitic infections will become more widely recognized in areas where parasites are endemic and not endemic. Generally, these methods are nonautomated and require extensive bench experience for accurate performance and interpretation.

Immunodeficiency-associated vaccine-derived polioviruses (iVDPVs) have been isolated from primary immunodeficiency (PID) patients exposed to oral poliovirus vaccine (OPV). Patients may excrete poliovirus strains for months or years; the excreted viruses are frequently highly divergent from the parental OPV and have been shown to be as neurovirulent as wild virus. Thus, these patients represent a potential reservoir for transmission of neurovirulent polioviruses in the post-eradication era. In support of WHO recommendations to better estimate the prevalence of poliovirus excreters among PIDs and characterize genetic evolution of these strains, 635 patients including 570 with primary antibody deficiencies and 65 combined immunodeficiencies were studied from 13 OPV-using countries. Two stool samples were collected over 4 days, tested for enterovirus, and the poliovirus positive samples were sequenced. Thirteen patients (2%) excreted polioviruses, most for less than 2 months following identification of infection. Five (0.8%) were classified as iVDPVs (only in combined immunodeficiencies and mostly poliovirus serotype 2). Non-polio enteroviruses were detected in 30 patients (4.7%). Patients with combined immunodeficiencies had increased risk of delayed poliovirus clearance compared to primary antibody deficiencies. Usually, iVDPV was detected in subjects with combined immunodeficiencies in a short period of time after OPV exposure, most for less than 6 months. Surveillance for poliovirus excretion among PID patients should be reinforced until polio eradication is certified and the use of OPV is stopped. Survival rates among PID patients are improving in lower and middle income countries, and iVDPV excreters are identified more frequently. Antivirals or enhanced immunotherapies presently in development represent the only potential means to manage the treatment of prolonged excreters and the risk they present to the polio endgame.

Multiple imputation is a popular approach to handling missing data. Although it was originally motivated by survey nonresponse problems, it has been readily applied to other data settings. However, its general behavior still remains unclear when applied to survey data with complex sample designs, including clustering. Recently, Lewis et al. (2014) compared single-and multiple-imputation analyses for certain incomplete variables in the 2008 National Ambulatory Medicare Care Survey, which has a nationally representative, multistage, and clustered sampling design. Their study results suggested that the increase of the variance estimate due to multiple imputation compared with single imputation largely disappears for estimates with large design effects. We complement their empirical research by providing some theoretical reasoning. We consider data sampled from an equally weighted, single-stage cluster design and characterize the process using a balanced, one-way normal random-effects model. Assuming that the missingness is completely at random, we derive analytic expressions for the within-and between-multiple-imputation variance estimators for the mean estimator, and thus conveniently reveal the impact of design effects on these variance estimators. We propose approximations for the fraction of missing information in clustered samples, extending previous results for simple random samples. We discuss some generalizations of this research and its practical implications for data release by statistical agencies. © Statistics Sweden.

A poliomyelitis outbreak caused by type 1 circulating vaccine-derived polioviruses (cVDPVs) was identified in China in 2004. Six independent cVDPVs (eight isolates) could be grouped into a single cluster with pathways of divergence different from a single cVDPV progenitor, which circulated and evolved into both a highly neurovirulent lineage and a less neurovirulent lineage. They were as neurovirulent as the wild type 1 Mahoney strain, recombination was absent, and their nucleotide 480-G was identical to that of the Sabin strain. The Guizhou/China cVDPV strains shared 4 amino acid replacements in the NAg sites: 3 located at the BC loop, which may underlie the aberrant results of the ELISA intratypic differentiation (ITD) test. The complete ORF tree diverged into two main branches from a common ancestral infection estimated to have occurred in about mid-September 2003, nine months before the appearance of the VDPV case, which indicated recently evolved VDPV. Further, recombination with species C enteroviruses may indicate the presence and density of these enteroviruses in the population and prolonged virus circulation in the community. The aforementioned cVDPVs has important implications in the global initiative to eradicate polio: high quality surveillance permitted earliest detection and response.

Wait time is the differences between the time a patient arrives in the emergency department (ED) and the time an ED provider examines that patient. This study focuses on the development of a negative binomial model to examine factors associated with ED wait time using the National Hospital Ambulatory Medical Care Survey (NHAMCS). Conducted by National Center for Health Statistics (NCHS), NHAMCS has been gathering, analyzing, and disseminating information annually about visits made for medical care to hospital outpatient department and EDs since 1992. To analyze ED wait times, a negative binomial model was fit to the ED visit data using publically released micro data from the 2009 NHAMCS. In this model, the wait time is the dependent variable while hospital, patient, and visit characteristics are the independent variables. Wait time was collapsed into discrete values representing 15 minutes intervals. The findings are presented.

How many imputations are sufficient in multiple imputations? The answer given by different researchers varies from as few as 2 - 3 to as many as hundreds. Perhaps no single number of imputations would fit all situations. In this study, η, the minimally sufficient number of imputations, was determined based on the relationship between m, the number of imputations, and ω, the standard error of imputation variances using the 2012 National Ambulatory Medical Care Survey (NAMCS) Physician Workflow mail survey. Five variables of various value ranges, variances, and missing data percentages were tested. For all variables tested, ω decreased as m increased. The m value above which the cost of further increase in m would outweigh the benefit of reducing ω was recognized as the η. This method has a potential to be used by anyone to determine η that fits his or her own data situation.

Laboratory diagnosis has played a critical role in the Global Polio Eradication Initiative (GPEI) since 1988 by isolating and identifying poliovirus (PV) from stool specimens by using cell culture, as a highly sensitive system to detect PV. In the present study, we aimed to develop a molecular method to detect PV directly from stool extracts with a high efficiency comparable to that of cell culture. We developed a method to efficiently amplify the entire capsid-coding region of human enteroviruses (EV) including PV. cDNAs of the entire capsid-coding region (3.9 kb) were obtained from as few as 50 copies of PV genomes. PV was detected from the cDNAs by an improved PV-specific real-time RT-PCR system and nucleotide sequence analysis of the VP1-coding region. For assay validation, we analyzed 84 stool extracts that were positive for PV in cell culture and detected PV genome from 100% of the extracts (84/84 samples) by this method in combination with a PV-specific extraction method. PV could be detected from 2/4 samples of stool extracts that were negative for PV in cell culture. In PV-positive samples, EV species C viruses were also detected with a high frequency (27%, 23/86 samples). This method would be useful for direct detection of PV from the stool extracts without using cell culture.

Since 2005, a large poliomyelitis outbreak associated with type 2 circulating vaccine-derived poliovirus (cVDPV2) has occurred in northern Nigeria, where immunization coverage with trivalent oral poliovirus vaccine (tOPV) has been low. Phylogenetic analysis of P1/capsid region sequences of isolates from each of the 403 cases reported in 2005 to 2011 resolved the outbreak into 23 independent type 2 vaccine-derived poliovirus (VDPV2) emergences, at least 7 of which established circulating lineage groups. Virus from one emergence (lineage group 2005-8; 361 isolates) was estimated to have circulated for over 6 years. The population of the major cVDPV2 lineage group expanded rapidly in early 2009, fell sharply after two tOPV rounds in mid-2009, and gradually expanded again through 2011. The two major determinants of attenuation of the Sabin 2 oral poliovirus vaccine strain (A481 in the 5'-untranslated region [5'-UTR] and VP1-Ile143) had been replaced in all VDPV2 isolates; most A481 5'-UTR replacements occurred by recombination with other enteroviruses. cVDPV2 isolates representing different lineage groups had biological properties indistinguishable from those of wild polioviruses, including efficient growth in neuron-derived HEK293 cells, the capacity to cause paralytic disease in both humans and PVR-Tg21 transgenic mice, loss of the temperature-sensitive phenotype, and the capacity for sustained person-to-person transmission. We estimate from the poliomyelitis case count and the paralytic case-to-infection ratio for type 2 wild poliovirus infections that approximately 700,000 cVDPV2 infections have occurred during the outbreak. The detection of multiple concurrent cVDPV2 outbreaks in northern Nigeria highlights the risks of cVDPV emergence accompanying tOPV use at low rates of coverage in developing countries.

The 2005 hurricane season caused extensive damage and induced a mass migration of approximately 1.1 million people from southern Louisiana in the United States. Current and accurate estimates of population size and demographics and an assessment of the critical needs for public services were required to guide recovery efforts. Since forecasts using pre-hurricane data may produce inaccurate estimates of the post-hurricane population, a household survey in 18 hurricane-affected parishes was conducted to provide timely and credible information on the size of these populations, their demographics and their condition. This paper describes the methods used, the challenges encountered, and the key factors for successful implementation. This post-disaster survey was unique because it identified the needs of the people in the affected parishes and quantified the number of people with these needs. Consequently, this survey established new population and health indicator baselines that otherwise would have not been available to guide the relief and recovery efforts in southern Louisiana.

OBJECTIVE: This report is a summary of hospital preparedness for responding to public health emergencies, including mass casualties and epidemics of naturally occurring diseases such as influenza. METHODS: Data are from an emergency response preparedness supplement to the 2008 National Hospital Ambulatory Medical Care Survey, which uses a national probability sample of nonfederal general and short-stay hospitals in the United States. Sample data were weighted to produce national estimates.

OBJECTIVES: This methods report provides an overview of the redesigned National Home and Hospice Care Survey (NHHCS) conducted in 2007. NHHCS is a national probability sample survey that collects data on U.S. home health and hospice care agencies, their staffs and services, and the people they serve. The redesigned survey included computerized data collection, greater survey content, increased sample sizes for current home health care patients and hospice care discharges, and a first-ever supplemental survey called the National Home Health Aide Survey. METHODS: The 2007 NHHCS was conducted between August 2007 and February 2008. NHHCS used a two-stage probability sampling design in which agencies providing home health and/or hospice care were sampled. Then, up to 10 current patients were sampled from each home health care agency, up to 10 discharges from each hospice care agency, and a combination of up to 10 patients/discharges from each agency that provided both home health and hospice care services. In-person interviews were conducted with agency directors and their designated staff; no interviews were conducted directly with patients. The survey instrument contained agency- and person-level modules, sampling modules, and a self-administered staffing questionnaire. RESULTS: Data were collected on 1036 agencies, 4683 current home health care patients, and 4733 hospice care discharges. The first-stage agency weighted response rate (for differential probabilities of selection) was 59%. The second-stage patient/discharge weighted response rate was 96%. Three public-use files were released: an agency-level file, a patient/discharge-level file, and a medication file. The files include sampling weights, which are necessary to generate national estimates, and design variables to enable users to calculate accurate standard errors.