Case Investigation and Contact Tracing Efforts From Health Departments in the United States, November 2020 to December 2021.

BACKGROUND: Sixty-four state, local, and territorial health departments (HDs) in the United States report monthly performance metrics on coronavirus disease 2019 (COVID-19) case investigation and contact tracing (CI/CT) activities. We describe national CI/CT efforts from 25 October 2020 through 24 December 2021, which included 3 peaks in COVID-19 case reporting. METHODS: Standardized CI/CT data elements submitted by the 64 HDs were summarized as monthly performance metrics for each HD and the nation. These included measures of CI/CT completeness, timeliness, and workloads. We calculated contact tracing efficacy as the proportion of new cases that occurred in persons identified as contacts within the 14 days before the case was reported. RESULTS: A total of 44 309 796 COVID-19 cases were reported to HDs, with completed HD interviews in 18 153 353 (41%). Less than half of interviews yielded ≥1 contact. A total of 19 939 376 contacts were identified; 11 632 613 were notified (58%), with 3 618 846 undergoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing within 14 days of notification. Of the total reported cases, 2 559 383 occurred in recently identified contacts. CONCLUSIONS: We document the resource-intense nationwide effort by US HDs to mitigate the impact of COVID-19 through CI/CT before and after vaccines became widely available. These results document the coverage and performance of CI/CT despite case surges and fluctuating workforce and workloads.

Spatial and temporal clustering of patients hospitalized with laboratory-confirmed influenza in the United States.

BACKGROUND: Timing of influenza spread across the United States is dependent on factors including local and national travel patterns and climate. Local epidemic intensity may be influenced by social, economic and demographic patterns. Data are needed to better explain how local socioeconomic factors influence both the timing and intensity of influenza seasons to result in national patterns. METHODS: To determine the spatial and temporal impacts of socioeconomics on influenza hospitalization burden and timing, we used population-based laboratory-confirmed influenza hospitalization surveillance data from the CDC-sponsored Influenza Hospitalization Surveillance Network (FluSurv-NET) at up to 14 sites from the 2009/2010 through 2013/2014 seasons (n = 35,493 hospitalizations). We used a spatial scan statistic and spatiotemporal wavelet analysis, to compare temporal patterns of influenza spread between counties and across the country. RESULTS: There were 56 spatial clusters identified in the unadjusted scan statistic analysis using data from the 2010/2011 through the 2013/2014 seasons, with relative risks (RRs) ranging from 0.09 to 4.20. After adjustment for socioeconomic factors, there were five clusters identified with RRs ranging from 0.21 to 1.20. In the wavelet analysis, most sites were in phase synchrony with one another for most years, except for the H1N1 pandemic year (2009-2010), wherein most sites had differential epidemic timing from the referent site in Georgia. CONCLUSIONS: Socioeconomic factors strongly impact local influenza hospitalization burden. Influenza phase synchrony varies by year and by socioeconomics, but is less influenced by socioeconomics than is disease burden.

Salmonella and the changing environment: systematic review using New York State as a model.

Salmonella is a public health concern, for which a complex interplay between host, agent, and environment exists. An improved understanding of causal processes can be used to better gauge the causes and trajectory of Salmonella in a changing environment. This would be useful in determining the impact of climate change on the New York State (NYS) environment, the effect of climate change on Salmonella in NYS, factors contributing to Salmonella vulnerability in humans, and aspects of climate change and Salmonella which necessitate further research. A systematic review was conducted to study associations between Salmonella and the environment. Using the search criteria, a total of 91 relevant articles were identified from four electronic databases. Key information was abstracted, organized, and synthesized to identify causal processes and linkages between climate change, the environment of NYS, and Salmonella-related outcomes, as well as risk factors to characterize Salmonella vulnerabilities. Three inter-related domains were identified for consideration and application to epidemiological research to confirm and extrapolate disease patterns using climate change scenarios: improved quantification of causal relationships, inclusion of factors linked to sectors not immediately associated with the exposure and outcome, and increased capacity to validate models in diverse settings.

Epidemiology of Invasive Group B Streptococcal Infections Among Nonpregnant Adults in the United States, 2008-2016.

Importance: Group B Streptococcus (GBS) is an important cause of invasive bacterial disease. Previous studies have shown a substantial and increasing burden of GBS infections among nonpregnant adults, particularly older adults and those with underlying medical conditions. Objective: To update trends of invasive GBS disease among US adults using population-based surveillance data. Design, Setting, and Participants: In this population-based surveillance study, a case was defined as isolation of GBS from a sterile site between January 1, 2008, and December 31, 2016. Demographic and clinical data were abstracted from medical records. Rates were calculated using US Census data. Antimicrobial susceptibility testing and serotyping were performed on a subset of isolates. Case patients were residents of 1 of 10 catchment areas of the Active Bacterial Core surveillance (ABCs) network, representing approximately 11.5% of the US adult population. Patients were included in the study if they were nonpregnant, were 18 years or older, were residents of an ABCs catchment site, and had a positive GBS culture from a normally sterile body site. Main Outcomes and Measures: Trends in GBS cases overall and by demographic characteristics (sex, age, and race), underlying clinical conditions of patients, and isolate characteristics are described. Results: The ABCs network detected 21 250 patients with invasive GBS among nonpregnant adults from 2008 through 2016. The GBS incidence in this population increased from 8.1 cases per 100 000 population in 2008 to 10.9 in 2016 (P = .002 for trend). There were 3146 cases reported in 2016 (59% male; median age, 64 years; age range, 18-103 years). The GBS incidence was higher among men than women and among blacks than whites and increased with age. Projected to the US population, an estimated 27 729 cases of invasive disease and 1541 deaths occurred in the United States in 2016. Ninety-five percent of cases in 2016 occurred in someone with at least 1 underlying condition, most commonly obesity (53.9%) and diabetes (53.4%). Resistance to clindamycin increased from 37.0% of isolates in 2011 to 43.2% in 2016 (P = .02). Serotypes Ia, Ib, II, III, and V accounted for 86.4% of isolates in 2016; serotype IV increased from 4.7% in 2008 to 11.3% in 2016 (P < .001 for trend). Conclusions and Relevance: The public health burden of invasive GBS disease among nonpregnant adults is substantial and continues to increase. Chronic diseases, such as obesity and diabetes, may contribute.

Current Epidemiology and Trends in Invasive Haemophilus influenzae Disease-United States, 2009-2015.

Background: Following Haemophilus influenzae serotype b (Hib) conjugate vaccine introduction in the 1980s, Hib disease in young children dramatically decreased, and epidemiology of invasive H. influenzae changed. Methods: Active surveillance for invasive H. influenzae disease was conducted through Active Bacterial Core surveillance sites. Incidence rates were directly standardized to the age and race distribution of the US population. Results: During 2009-2015, the estimated mean annual incidence of invasive H. influenzae disease was 1.70 cases per 100000 population. Incidence was highest among adults aged ≥65 years (6.30) and children aged <1 year (8.45); many cases in infants aged <1 year occurred during the first month of life in preterm or low-birth-weight infants. Among children aged <5 years (incidence: 2.84), incidence was substantially higher in American Indian and Alaska Natives AI/AN (15.19) than in all other races (2.62). Overall, 14.5% of cases were fatal; case fatality was highest among adults aged ≥65 years (20%). Nontypeable H. influenzae had the highest incidence (1.22) and case fatality (16%), as compared with Hib (0.03; 4%) and non-b encapsulated serotypes (0.45; 11%). Compared with 2002-2008, the estimated incidence of invasive H. influenzae disease increased by 16%, driven by increases in disease caused by serotype a and nontypeable strains. Conclusions: Invasive H. influenzae disease has increased, particularly due to nontypeable strains and serotype a. A considerable burden of invasive H. influenzae disease affects the oldest and youngest age groups, particularly AI/AN children. These data can inform prevention strategies, including vaccine development.

Foodborne Illness Outbreak Investigation Training Needs: A Survey Among State Public Health Staff in the Northeast and Mid-Atlantic United States.

CONTEXT: In 2011, the Food Safety and Modernization Act established Integrated Food Safety Centers of Excellence across the United States to train, educate, and enhance the skill of foodborne illness outbreak investigation teams. To target regional training efforts, the New York Integrated Food Safety Center of Excellence (NYCoE) identified training needs in food safety and foodborne illness investigations among public heath staff in 11 states and 1 large metropolitan area in the Northeast. OBJECTIVE: To identify topics so as to develop training materials relevant to food safety and foodborne disease outbreaks in order to improve and impact foodborne outbreak investigations regionally and nationally. DESIGN: Cross-sectional, paper-based survey conducted in January-February 2016. SETTING: Eleven Northeast and Mid-Atlantic states, and 1 large metropolitan area. PARTICIPANTS: Foodborne illness outbreak investigators in the NYCoE region. MAIN OUTCOME MEASURES: Identification of training needs, as self-reported by participants, regarding general foodborne outbreak investigation needs and those specific to epidemiologists, environmental health specialists, and laboratorians. Topics included basic food safety/processing knowledge, communication and metrics, and training formats. Information regarding demographics, utility of the NYCoE, and certificate programs was also collected. RESULTS: Surveys returned from 33 respondents (from 10 states and 1 metropolitan area) identified metrics (100%), increasing use of culture-independent diagnostic tests (85%), and guidance on implementation of the Council to Improve Foodborne Outbreak Response (guidelines (89%) as the top training needs. By field, epidemiologists cited training in applying whole genome sequencing (100%), environmental health specialists cited training on the National Outbreak Reporting System (67%), and laboratorians cited training on whole genome sequencing (91%) as important. Short, online, or in-person, 1- to 2-day trainings were the preferred training formats (≥91%). Respondents wanted certificate programs in food safety (73%). CONCLUSION: New diagnostic and molecular techniques are highly desirable topics for trainings, as is understanding national guidelines and outcome measures. Shorter and hands-on training formats, as well as certificate programs, are desirable. The NYCoE used the results of this survey to (i) select training topics for a Food Safety symposium conducted in July 2016 and to (ii) drive other activities.

Reduced Severity of Pertussis in Persons With Age-Appropriate Pertussis Vaccination-United States, 2010-2012.

BACKGROUND: In 2012, >48000 pertussis cases were reported in the United States. Many cases occurred in vaccinated persons, showing that pertussis vaccination does not prevent all pertussis cases. However, pertussis vaccination may have an impact on disease severity. METHODS: We analyzed data on probable and confirmed pertussis cases reported through Enhanced Pertussis Surveillance (Emerging Infections Program Network) between 2010 and 2012. Surveillance data were collected through physician and patient interview and vaccine registries. We assessed whether having received an age-appropriate number of pertussis vaccines (AAV) (for persons aged ≥3 months) was associated with reduced odds of posttussive vomiting, a marker of more clinically significant illness, or of severe pertussis (seizure, encephalopathy, pneumonia, and/or hospitalization). Adjusted odds ratios were calculated using multivariable logistic regression. RESULTS: Among 9801 pertussis patients aged ≥3 months, 77.6% were AAV. AAV status was associated with a 60% reduction in odds of severe disease in children aged 7 months-6 years in multivariable logistic regression and a 30% reduction in odds of posttussive vomiting in persons aged 19 months-64 years. CONCLUSIONS: Serious pertussis symptoms and complications are less common among AAV pertussis patients, demonstrating that the positive impact of pertussis vaccination extends beyond decreasing risk of disease.

Impact of the US Maternal Tetanus, Diphtheria, and Acellular Pertussis Vaccination Program on Preventing Pertussis in Infants <2 Months of Age: A Case-Control Evaluation.

BACKGROUND: Infants aged <1 year are at highest risk for pertussis-related morbidity and mortality. In 2012, Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) vaccine was recommended for women during each pregnancy to protect infants in the first months of life; data on effectiveness of this strategy are currently limited. METHODS: We conducted a case-control evaluation among pertussis cases <2 months old with cough onset between 1 January 2011 and 31 December 2014 from 6 US Emerging Infection Program Network states. Controls were hospital-matched and selected by birth certificate. Mothers were interviewed to collect information on demographics, household characteristics, and healthcare providers. Provider-verified immunization history was obtained on mothers and infants. Mothers were considered vaccinated during pregnancy if Tdap was received ≥14 days before delivery; trimester was calculated using Tdap date, infant's date of birth, and gestational age. Odds ratios were calculated using multivariable conditional logistic regression; vaccine effectiveness (VE) was estimated as (1 - odds ratio) × 100%. RESULTS: A total of 240 cases and 535 controls were included; 17 (7.1%) case mothers and 90 (16.8%) control mothers received Tdap during the third trimester of pregnancy. The multivariable VE estimate for Tdap administered during the third trimester of pregnancy was 77.7% (95% confidence interval [CI], 48.3%-90.4%); VE increased to 90.5% (95% CI, 65.2%-97.4%) against hospitalized cases. CONCLUSIONS: Vaccination during pregnancy is an effective way to protect infants during the early months of life. With a continuing resurgence in pertussis, efforts should focus on maximizing Tdap uptake among pregnant women.

Social determinants of influenza hospitalization in the United States.

BACKGROUND: Influenza hospitalizations result in substantial morbidity and mortality each year. Little is known about the association between influenza hospitalization and census tract-based socioeconomic determinants beyond the effect of individual factors. OBJECTIVE: To evaluate whether census tract-based determinants such as poverty and household crowding would contribute significantly to the risk of influenza hospitalization above and beyond individual-level determinants. METHODS: We analyzed 33 515 laboratory-confirmed influenza-associated hospitalizations that occurred during the 2009-2010 through 2013-2014 influenza seasons using a population-based surveillance system at 14 sites across the United States. RESULTS: Using a multilevel regression model, we found that individual factors were associated with influenza hospitalization with the highest adjusted odds ratio (AOR) of 9.20 (95% CI 8.72-9.70) for those ≥65 vs 5-17 years old. African Americans had an AOR of 1.67 (95% CI 1.60-1.73) compared to Whites, and Hispanics had an AOR of 1.21 (95% CI 1.16-1.26) compared to non-Hispanics. Among census tract-based determinants, those living in a tract with ≥20% vs <5% of persons living below poverty had an AOR of 1.31 (95% CI 1.16-1.47), those living in a tract with ≥5% vs <5% of persons living in crowded conditions had an AOR of 1.17 (95% CI 1.11-1.23), and those living in a tract with ≥40% vs <5% female heads of household had an AOR of 1.32 (95% CI 1.25-1.40). CONCLUSION: Census tract-based determinants account for 11% of the variability in influenza hospitalization.

Generalisability of vaccine effectiveness estimates: an analysis of cases included in a postlicensure evaluation of 13-valent pneumococcal conjugate vaccine in the USA.

OBJECTIVES: External validity, or generalisability, is the measure of how well results from a study pertain to individuals in the target population. We assessed generalisability, with respect to socioeconomic status, of estimates from a matched case-control study of 13-valent pneumococcal conjugate vaccine effectiveness for the prevention of invasive pneumococcal disease in children in the USA. DESIGN: Matched case-control study. SETTING: Thirteen active surveillance sites for invasive pneumococcal disease in the USA. PARTICIPANTS: Cases were identified from active surveillance and controls were age and zip code matched. OUTCOME MEASURES: Socioeconomic status was assessed at the individual level via parent interview (for enrolled individuals only) and birth certificate data (for both enrolled and unenrolled individuals) and at the neighbourhood level by geocoding to the census tract (for both enrolled and unenrolled individuals). Prediction models were used to determine if socioeconomic status was associated with enrolment. RESULTS: We enrolled 54.6% of 1211 eligible cases and found a trend toward enrolled cases being more affluent than unenrolled cases. Enrolled cases were slightly more likely to have private insurance at birth (p=0.08) and have mothers with at least some college education (p<0.01). Enrolled cases also tended to come from more affluent census tracts. Despite these differences, our best predictive model for enrolment yielded a concordance statistic of only 0.703, indicating mediocre predictive value. Variables retained in the final model were assessed for effect measure modification, and none were found to be significant modifiers of vaccine effectiveness. CONCLUSIONS: We conclude that although enrolled cases are somewhat more affluent than unenrolled cases, our estimates are externally valid with respect to socioeconomic status. Our analysis provides evidence that this study design can yield valid estimates and the assessing generalisability of observational data is feasible, even when unenrolled individuals cannot be contacted.

Impact of pregnancy on observed sex disparities among adults hospitalized with laboratory-confirmed influenza, FluSurv-NET, 2010-2012.

INTRODUCTION: Previous FluSurv-NET studies found that adult females had a higher incidence of influenza-associated hospitalizations than males. To identify groups of women at higher risk than men, we analyzed data from 14 FluSurv-NET sites that conducted population-based surveillance for laboratory-confirmed influenza-associated hospitalizations among residents of 78 US counties. METHODS: We analyzed 6292 laboratory-confirmed, geocodable (96%) adult cases collected by FluSurv-NET during the 2010-12 influenza seasons. We used 2010 US Census and 2008-2012 American Community Survey data to calculate overall age-adjusted and age group-specific female:male incidence rate ratios (IRR) by race/ethnicity and census tract-level poverty. We used national 2010 pregnancy rates to estimate denominators for pregnant women aged 18-49. We calculated male:female IRRs excluding them and IRRs for pregnant:non-pregnant women. RESULTS: Overall, 55% of laboratory-confirmed influenza cases were female. Female:male IRRs were highest for females aged 18-49 of high neighborhood poverty (IRR 1.50, 95% CI 1.30-1.74) and of Hispanic ethnicity (IRR 1.70, 95% CI 1.34-2.17). These differences disappeared after excluding pregnant women. Overall, 26% of 1083 hospitalized females aged 18-49 were pregnant. Pregnant adult females were more likely to have influenza-associated hospitalizations than their non-pregnant counterparts (relative risk [RR] 5.86, 95% CI 5.12-6.71), but vaccination levels were similar (25.5% vs 27.8%). CONCLUSIONS: Overall rates of influenza-associated hospitalization were not significantly different for men and women after excluding pregnant women. Among women aged 18-49, pregnancy increased the risk of influenza-associated hospitalization sixfold but did not increase the likelihood of vaccination. Improving vaccination rates in pregnant women should be an influenza vaccination priority.

Influenza Vaccination Modifies Disease Severity Among Community-dwelling Adults Hospitalized With Influenza.

Background: We investigated the effect of influenza vaccination on disease severity in adults hospitalized with laboratory-confirmed influenza during 2013-14, a season in which vaccine viruses were antigenically similar to those circulating. Methods: We analyzed data from the 2013-14 influenza season and used propensity score matching to account for the probability of vaccination within age strata (18-49, 50-64, and ≥65 years). Death, intensive care unit (ICU) admission, and hospital and ICU lengths of stay (LOS) were outcome measures for severity. Multivariable logistic regression and competing risk models were used to compare disease severity between vaccinated and unvaccinated patients, adjusting for timing of antiviral treatment and time from illness onset to hospitalization. Results: Influenza vaccination was associated with a reduction in the odds of in-hospital death among patients aged 18-49 years (adjusted odds ratios [aOR] = 0.21; 95% confidence interval [CI], 0.05 to 0.97), 50-64 years (aOR = 0.48; 95% CI, 0.24 to 0.97), and ≥65 years (aOR = 0.39; 95% CI, 0.17 to 0.66). Vaccination also reduced ICU admission among patients aged 18-49 years (aOR = 0.63; 95% CI, 0.42 to 0.93) and ≥65 years (aOR = 0.63; 95% CI, 0.48 to 0.81), and shortened ICU LOS among those 50-64 years (adjusted relative hazards [aRH] = 1.36; 95% CI, 1.06 to 1.74) and ≥65 years (aRH = 1.34; 95% CI, 1.06 to 1.73), and hospital LOS among 50-64 years (aRH = 1.13; 95% CI, 1.02 to 1.26) and ≥65 years (aRH = 1.24; 95% CI, 1.13 to 1.37). Conclusions: Influenza vaccination during 2013-14 influenza season attenuated adverse outcome among adults that were hospitalized with laboratory-confirmed influenza.

Incidence and Trends of Infections with Pathogens Transmitted Commonly Through Food and the Effect of Increasing Use of Culture-Independent Diagnostic Tests on Surveillance - Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2013-2016.

Foodborne diseases represent a substantial public health concern in the United States. CDC's Foodborne Diseases Active Surveillance Network (FoodNet) monitors cases reported from 10 U.S. sites* of laboratory-diagnosed infections caused by nine enteric pathogens commonly transmitted through food. This report describes preliminary surveillance data for 2016 on the nine pathogens and changes in incidences compared with 2013-2015. In 2016, FoodNet identified 24,029 infections, 5,512 hospitalizations, and 98 deaths caused by these pathogens. The use of culture-independent diagnostic tests (CIDTs) by clinical laboratories to detect enteric pathogens has been steadily increasing since FoodNet began surveying clinical laboratories in 2010 (1). CIDTs complicate the interpretation of FoodNet surveillance data because pathogen detection could be affected by changes in health care provider behaviors or laboratory testing practices (2). Health care providers might be more likely to order CIDTs because these tests are quicker and easier to use than traditional culture methods, a circumstance that could increase pathogen detection (3). Similarly, pathogen detection could also be increasing as clinical laboratories adopt DNA-based syndromic panels, which include pathogens not often included in routine stool culture (4,5). In addition, CIDTs do not yield isolates, which public health officials rely on to distinguish pathogen subtypes, determine antimicrobial resistance, monitor trends, and detect outbreaks. To obtain isolates for infections identified by CIDTs, laboratories must perform reflex culture†; if clinical laboratories do not, the burden of culturing falls to state public health laboratories, which might not be able to absorb that burden as the adoption of these tests increases (2). Strategies are needed to preserve access to bacterial isolates for further characterization and to determine the effect of changing trends in testing practices on surveillance.

Increased Antiviral Treatment Among Hospitalized Children and Adults With Laboratory-Confirmed Influenza, 2010-2015.

(See the Editorial Commentary by Martin on pages 368-9.)Using population-based surveillance data, we analyzed antiviral treatment among hospitalized patients with laboratory-confirmed influenza. Treatment increased after the influenza A(H1N1) 2009 pandemic from 72% in 2010-2011 to 89% in 2014-2015 (P < .001). Overall, treatment was higher in adults (86%) than in children (72%); only 56% of cases received antivirals on the day of admission.

Penicillin Use in Meningococcal Disease Management: Active Bacterial Core Surveillance Sites, 2009.

In 2009, in the Active Bacterial Core surveillance sites, penicillin was not commonly used to treat meningococcal disease. This is likely because of inconsistent availability of antimicrobial susceptibility testing and ease of use of third-generation cephalosporins. Consideration of current practices may inform future meningococcal disease management guidelines.

Bias with respect to socioeconomic status: A closer look at zip code matching in a pneumococcal vaccine effectiveness study.

In 2010, 13-valent pneumococcal conjugate vaccine (PCV13) was introduced in the US for prevention of invasive pneumococcal disease in children. Individual-level socioeconomic status (SES) is a potential confounder of the estimated effectiveness of PCV13 and is often controlled for in observational studies using zip code as a proxy. We assessed the utility of zip code matching for control of SES in a post-licensure evaluation of the effectiveness of PCV13 (calculated as [1-matched odds ratio]*100). We used a directed acyclic graph to identify subsets of confounders and collected SES variables from birth certificates, geo-coding, a parent interview, and follow-up with medical providers. Cases tended to be more affluent than eligible controls (for example, 48.3% of cases had private insurance vs. 44.6% of eligible controls), but less affluent than enrolled controls (52.9% of whom had private insurance). Control of confounding subsets, however, did not result in a meaningful change in estimated vaccine effectiveness (original estimate: 85.1%, 95% CI 74.8-91.9%; adjusted estimate: 82.5%, 95% CI 65.6-91.1%). In the context of a post-licensure vaccine effectiveness study, zip code appears to be an adequate, though not perfect, proxy for individual SES.

Vital Signs: Epidemiology of Sepsis: Prevalence of Health Care Factors and Opportunities for Prevention.

BACKGROUND: Sepsis is a serious and often fatal clinical syndrome, resulting from infection. Information on patient demographics, risk factors, and infections leading to sepsis is needed to integrate comprehensive sepsis prevention, early recognition, and treatment strategies. METHODS: To describe characteristics of patients with sepsis, CDC and partners conducted a retrospective chart review in four New York hospitals. Random samples of medical records from adult and pediatric patients with administrative codes for severe sepsis or septic shock were reviewed. RESULTS: Medical records of 246 adults and 79 children (aged birth to 17 years) were reviewed. Overall, 72% of patients had a health care factor during the 30 days before sepsis admission or a selected chronic condition likely to require frequent medical care. Pneumonia was the most common infection leading to sepsis. The most common pathogens isolated from blood cultures were Escherichia coli in adults aged ≥18 years, Klebsiella spp. in children aged ≥1 year, and Enterococcus spp. in infants aged <1 year; for 106 (33%) patients, no pathogen was isolated. Eighty-two (25%) patients with sepsis died, including 65 (26%) adults and 17 (22%) infants and children. CONCLUSIONS: Infection prevention strategies (e.g., vaccination, reducing transmission of pathogens in health care environments, and appropriate management of chronic diseases) are likely to have a substantial impact on reducing sepsis. CDC, in partnership with organizations representing clinicians, patients, and other stakeholders, is launching a comprehensive campaign to demonstrate that prevention of infections that cause sepsis, and early recognition of sepsis, are integral to overall patient safety.

Case-Control Study of Vaccine Effectiveness in Preventing Laboratory-Confirmed Influenza Hospitalizations in Older Adults, United States, 2010-2011.

BACKGROUND: Older adults are at increased risk of influenza-associated complications, including hospitalization, but influenza vaccine effectiveness (VE) data are limited for this population. We conducted a case-control study to estimate VE to prevent laboratory-confirmed influenza hospitalizations among adults aged ≥50 years in 11 US Emerging Infections Program hospitalization surveillance sites. METHODS: Cases were influenza infections (confirmed by reverse-transcription polymerase chain reaction) in adults aged ≥50 years hospitalized during the 2010-2011 influenza season, identified through Emerging Infections Program surveillance. Community controls, identified through home telephone lists, were matched by age group (±5 years), county, and month of hospitalization for case patients. Vaccination status was determined by self-report (with location and date) or medical records. Conditional logistic regression models were used to calculate adjusted VE (aVE) estimates (100 × [1 - adjusted odds ratio]), adjusting for sex, race, socioeconomic factors, smoking, chronic medical conditions, recent hospitalization for a respiratory condition, and functional status. RESULTS: Among case patients, 205 of 368 (55%) were vaccinated, compared with 489 of 773 controls (63%). Case patients were more likely to be of nonwhite race and more likely to have ≥2 chronic health conditions, a recent hospitalization for a respiratory condition, an income <$35 000, and a lower functional status score (P < .01 for all). The aVE was 56.8% (95% confidence interval, 34.1%-71.7%) and was similar across age groups, including adults ≥75 years (aVE, 57.3%; 15.9%-78.4%). CONCLUSIONS: During 2010-2011, influenza vaccination was associated with a significant reduction in the risk of laboratory-confirmed influenza hospitalization among adults aged ≥50 years, regardless of age group.

Utility of Keywords from Chest Radiograph Reports for Pneumonia Surveillance Among Hospitalized Patients with Influenza: The CDC Influenza Hospitalization Surveillance Network, 2008-2009.

OBJECTIVE: Transcripts from admission chest radiographs could aid in identification of pneumonia cases for public health surveillance. We assessed the reliability of radiographic data abstraction and performance of radiographic key terms to identify pneumonia in patients hospitalized with laboratory-confirmed influenza virus infection. METHODS: We used data on patients hospitalized with laboratory-confirmed influenza virus infection from October 2008 through December 2009 from 10 geographically diverse U.S. study sites participating in the Influenza Hospitalization Surveillance Network (FluSurv-NET). Radiographic key terms (i.e., bronchopneumonia, consolidation, infiltrate, airspace density, and pleural effusion) were abstracted from final impressions of chest radiograph reports. We assessed the reliability of radiographic data abstraction by examining the percent agreement and Cohen's k statistic between clinicians and surveillance staff members. Using a composite reference standard for presence or absence of pneumonia based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes and discharge summary data, we calculated sensitivity, specificity, positive predictive value (PPV), and percent agreement for individual and combined radiographic key terms. RESULTS: For each radiographic key term, the percent agreement between clinicians and surveillance staff members ranged from 89.4% to 98.6% and Cohen's k ranged from 0.46 (moderate) to 0.84 (almost perfect). The combination of bronchopneumonia or consolidation or infiltrate or airspace density terms had sensitivity of 66.5%, specificity of 89.2%, PPV of 80.4%, and percent agreement of 80.1%. Adding pleural effusion did not result in significant changes in sensitivity, specificity, PPV, or percent agreement. CONCLUSION: Radiographic key terms abstracted by surveillance staff members from final impressions of chest radiograph reports had moderate to almost perfect reliability and could be used to identify pneumonia among patients hospitalized with laboratory-confirmed influenza virus infection. This method can inform pneumonia surveillance and aid in public health response.

Infection with Pathogens Transmitted Commonly Through Food and the Effect of Increasing Use of Culture-Independent Diagnostic Tests on Surveillance--Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2012-2015.

To evaluate progress toward prevention of enteric and foodborne illnesses in the United States, the Foodborne Diseases Active Surveillance Network (FoodNet) monitors the incidence of laboratory-confirmed infections caused by nine pathogens transmitted commonly through food in 10 U.S. sites. This report summarizes preliminary 2015 data and describes trends since 2012. In 2015, FoodNet reported 20,107 confirmed cases (defined as culture-confirmed bacterial infections and laboratory-confirmed parasitic infections), 4,531 hospitalizations, and 77 deaths. FoodNet also received reports of 3,112 positive culture-independent diagnostic tests (CIDTs) without culture-confirmation, a number that has markedly increased since 2012. Diagnostic testing practices for enteric pathogens are rapidly moving away from culture-based methods. The continued shift from culture-based methods to CIDTs that do not produce the isolates needed to distinguish between strains and subtypes affects the interpretation of public health surveillance data and ability to monitor progress toward prevention efforts. Expanded case definitions and strategies for obtaining bacterial isolates are crucial during this transition period.