Prioritizing vaccination based on analysis of community networks.

Many countries that had early access to COVID-19 vaccines implemented vaccination strategies that prioritized health care workers and the elderly. As barriers to access eased, vaccine prioritization strategies have been relaxed. However, these strategies are still an important tool for decision makers to manage new variants, plan for future booster shots, or stage mass vaccinations. This paper explores the impact of vaccine prioritization strategies using networks that represent communities with different demographics and connectivity. The impact of vaccination is compared to non-medical intervention to reduce transmission. Several sources of uncertainty are considered, including vaccine willingness and mask effectiveness. This paper finds that while prioritization strategies can have a large impact on reducing deaths and peak hospitalization, selecting the best strategy depends on community characteristics and the desired objective. Additionally, in some cases random vaccination performs as well as more targeted prioritization strategies. Understanding these trade-offs is important when planning vaccine distribution.

Analysis of mobility data to build contact networks for COVID-19.

As social distancing policies and recommendations went into effect in response to COVID-19, people made rapid changes to the places they visit. These changes are clearly seen in mobility data, which records foot traffic using location trackers in cell phones. While mobility data is often used to extract the number of customers that visit a particular business or business type, it is the frequency and duration of concurrent occupancy at those sites that governs transmission. Understanding the way people interact at different locations can help target policies and inform contact tracing and prevention strategies. This paper outlines methods to extract interactions from mobility data and build networks that can be used in epidemiological models. Several measures of interaction are extracted: interactions between people, the cumulative interactions for a single person, and cumulative interactions that occur at particular businesses. Network metrics are computed to identify structural trends which show clear changes based on the timing of stay-at-home orders. Measures of interaction and structural trends in the resulting networks can be used to better understand potential spreading events, the percent of interactions that can be classified as close contacts, and the impact of policy choices to control transmission.

Enhancing laboratory capacity during Ebola virus disease (EVD) heightened surveillance in Liberia: lessons learned and recommendations.

INTRODUCTION: Following a declaration by the World Health Organization that Liberia had successfully interrupted Ebola virus transmission on May 9th, 2015; the country entered a period of enhanced surveillance. The number of cases had significantly reduced prior to the declaration, leading to closure of eight out of eleven Ebola testing laboratories. Enhanced surveillance led to an abrupt increase in demand for laboratory services. We report interventions, achievements, lessons learned and recommendations drawn from enhancing laboratory capacity. METHODS: Using archived data, we reported before and after interventions that aimed at increasing laboratory capacity. Laboratory capacity was defined by number of laboratories with Ebola Virus Disease (EVD) testing capacity, number of competent staff, number of specimens tested, specimen backlog, daily and surge testing capacity, and turnaround time. Using Stata 14 (Stata Corporation, College Station, TX, USA), medians and trends were reported for all continuous variables. RESULTS: Between May and December 2015, interventions including recruitment and training of eight staff, establishment of one EVD laboratory facility, implementation of ten Ebola GeneXpert diagnostic platforms, and establishment of working shifts yielded an 8-fold increase in number of specimens tested, a reduction in specimens backlog to zero, and restoration of turn-around time to 24 hours. This enabled a more efficient surveillance system that facilitated timely detection and containment of two EVD clusters observed thereafter. CONCLUSION: Effective enhancement of laboratory services during high demand periods requires a combination of context-specific interventions. Building and ensuring sustainability of local capacity is an integral part of effective surveillance and disease outbreak response efforts.

Cryptococcus gattii infections in multiple states outside the US Pacific Northwest.

Clonal VGII subtypes (outbreak strains) of Cryptococcus gattii have caused an outbreak in the US Pacific Northwest since 2004. Outbreak-associated infections occur equally in male and female patients (median age 56 years) and usually cause pulmonary disease in persons with underlying medical conditions. Since 2009, a total of 25 C. gattii infections, 23 (92%) caused by non-outbreak strain C. gattii, have been reported from 8 non-Pacific Northwest states. Sixteen (64%) patients were previously healthy, and 21 (84%) were male; median age was 43 years (range 15-83 years). Ten patients who provided information reported no past-year travel to areas where C. gattii is known to be endemic. Nineteen (76%) patients had central nervous system infections; 6 (24%) died. C. gattii infection in persons without exposure to known disease-endemic areas suggests possible endemicity in the United States outside the outbreak-affected region; these infections appear to differ in clinical and demographic characteristics from outbreak-associated C. gattii. Clinicians outside the outbreak-affected areas should be aware of locally acquired C. gattii infection and its varied signs and symptoms.

Evaluating a standardized measure of healthcare personnel influenza vaccination.

BACKGROUND: Methods of measuring influenza vaccination of healthcare personnel (HCP) vary substantially, as do the groups of HCP that are included in any given set of measurements. Thus, comparison of vaccination rates across healthcare facilities is difficult. PURPOSE: The goal of the study was to determine the feasibility of implementing a standardized measure for reporting HCP influenza vaccination data in various types of healthcare facilities. METHODS: A total of 318 facilities recruited in four U.S. jurisdictions agreed to participate in the evaluation, including hospitals, long-term care facilities, dialysis clinics, ambulatory surgery centers, and physician practices. HCP in participating facilities were categorized as employees, credentialed non-employees, or other non-employees using standard definitions. Data were gathered using cross-sectional web-based surveys completed at three intervals between October 2010 and May 2011; data were analyzed in February 2012. RESULTS: 234 facilities (74%) completed all three surveys. Most facilities could report on-site employee vaccination; almost one third could not provide complete data on HCP vaccinated outside the facility, contraindications, or declinations, primarily due to missing non-employee data. Inability to determine vaccination status of credentialed and other non-employees was cited as a major barrier to measure implementation by 24% and 27% of respondents, respectively. CONCLUSIONS: Using the measure to report employee vaccination status was feasible for most facilities; tracking non-employee HCP was more challenging. Based on evaluation findings, the measure was revised to limit the types of non-employees included. Although the revised measure is less comprehensive, it is more likely to produce valid vaccination coverage estimates. Use of this standardized measure can inform quality improvement efforts and facilitate comparison of HCP influenza vaccination among facilities.

Reliability and validity of a standardized measure of influenza vaccination coverage among healthcare personnel.

OBJECTIVE: To evaluate the reliability and validity of a standardized measure of healthcare personnel (HCP) influenza vaccination. SETTING: Acute care hospitals, long-term care facilities, ambulatory surgery centers, physician practices, and dialysis centers from 3 US jurisdictions. PARTICIPANTS: Staff from 96 healthcare facilities randomly sampled from 234 facilities that completed pilot testing to assess the feasibility of the measure. METHODS: Reliability was assessed by comparing agreement between facility staff and project staff on the classification of HCP numerator (vaccinated at facility, vaccinated elsewhere, contraindicated, declined) and denominator (employees, credentialed nonemployees, other nonemployees) categories. To assess validity, facility staff completed a series of case studies to evaluate how closely classification of HCP groups aligned with the measure's specifications. In a modified Delphi process, experts rated face validity of the proposed measure elements on a Likert-type scale. RESULTS: Percent agreement was high for HCP vaccinated at the facility (99%) and elsewhere (95%) and was lower for HCP who declined vaccination (64%) or were medically contraindicated (64%). While agreement was high (more than 90%) for all denominator categories, many facilities' staff excluded nonemployees for whom numerator and denominator status was difficult to determine. Validity was lowest for credentialed and other nonemployees. CONCLUSIONS: The standardized measure of HCP influenza vaccination yields reproducible results for employees vaccinated at the facility and elsewhere. Adhering to true medical contraindications and tracking declinations should improve reliability. Difficulties in establishing denominators and determining vaccination status for credentialed and other nonemployees challenged the measure's validity and prompted revision to include a more limited group of nonemployees.

Validation of central line-associated bloodstream infection data in a voluntary reporting state: New Mexico.

BACKGROUND: In New Mexico, voluntary submission of central line-associated bloodstream infection (CLABSI) surveillance data via the National Healthcare Safety Network (NHSN) began in July 2008. Validation of CLABSI data is necessary to ensure quality, accuracy, and reliability of surveillance efforts. METHODS: We conducted a retrospective medical record review of 123 individuals with positive blood cultures who were admitted to adult intensive care units (ICU) at 6 New Mexico hospitals between November 2009 and March 2010. Blinded reviews were conducted independently by pairs of reviewers using standardized data collection instruments. Findings were compared between reviewers and with NHSN data. Discordant cases were reviewed and reconciled with hospital infection preventionists. RESULTS: Initially, 118 individuals were identified for medical record review. Seven ICU CLABSI events were identified by the reviewers. Data submitted to the NHSN revealed 8 ICU CLABSI events, 5 of which had not been identified for medical record review and 3 of which had been determined by reviewers to not be ICU CLABSI cases. Comparison of final case determinations for all 123 individuals with NHSN data resulted in a sensitivity of 66.7%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 96.5% for ICU CLABSI surveillance. CONCLUSIONS: There is need for ongoing quality improvement and validation processes to ensure accurate NHSN data.

Management and outcome of a varicella exposure in a neonatal intensive care unit: lessons for the vaccine era.

BACKGROUND: Varicella exposure in health care settings poses a threat to susceptible, immunocompromised hosts. We describe the management and outcome of a varicella exposure in a neonatal intensive care unit. METHODS: We reviewed the history of the index case, determination of the exposed cohort, medical management of exposed neonates, and assignment of health care workers based on exposure and immune status. We present the results of serologic testing of health care workers related to their history of varicella disease. RESULTS: Of 427 health care workers assessed at the time of the exposure, 13.1% were seronegative for varicella. Among 180 employees recorded as having a previous history of varicella, 9 were seronegative. A total of 34 infants received prophylaxis with intravenous immune globulin; acyclovir prophylaxis was added for those born at <28 weeks gestational age. The exposed cohort was isolated. No secondary cases of varicella occurred among patients or health care workers. CONCLUSION: Nosocomial varicella exposures require rapid assessment and response, which can be guided by a checklist of actions. Varicella immunity in health care workers cannot be assumed even among those born before 1980; institutional policies should adhere to the 2007 Centers for Disease Control and Prevention's definition of immunity to varicella for health care workers.