Anne Robertson

Influenza Vaccine Effectiveness Against 2009 Pandemic Influenza A(H1N1) Virus Differed by Vaccine Type During 2013–2014 in the United States

BACKGROUND The predominant strain during the 2013-2014 influenza season was 2009 pandemic influenza A(H1N1) virus (A[H1N1]pdm09). This vaccine-component has remained unchanged from 2009. METHODS The US Flu Vaccine Effectiveness Network enrolled subjects aged ≥6 months with medically attended acute respiratory illness (MAARI), including cough, with illness onset ≤7 days before enrollment. Influenza was confirmed by reverse-transcription polymerase chain reaction (RT-PCR). We determined the effectiveness of trivalent or quadrivalent inactivated influenza vaccine (IIV) among subjects ages ≥6 months and the effectiveness of quadrivalent live attenuated influenza vaccine (LAIV4) among children aged 2-17 years, using a test-negative design. The effect of prior receipt of any A(H1N1)pdm09-containing vaccine since 2009 on the effectiveness of current-season vaccine was assessed. RESULTS We enrolled 5999 subjects; 5637 (94%) were analyzed; 18% had RT-PCR-confirmed A(H1N1)pdm09-related MAARI. Overall, the effectiveness of vaccine against A(H1N1)pdm09-related MAARI was 54% (95% confidence interval [CI], 46%-61%). Among fully vaccinated children aged 2-17 years, the effectiveness of LAIV4 was 17% (95% CI, -39% to 51%) and the effectiveness of IIV was 60% (95% CI, 36%-74%). Subjects aged ≥9 years showed significant residual protection of any prior A(H1N1)pdm09-containing vaccine dose(s) received since 2009, as did children <9 years old considered fully vaccinated by prior season. CONCLUSIONS During 2013-2014, IIV was significantly effective against A(H1N1)pdm09. Lack of LAIV4 effectiveness in children highlights the importance of continued annual monitoring of effectiveness of influenza vaccines in the United States.

Universal MRSA nasal surveillance: characterization of outcomes at a tertiary care center and implications for infection control.

Background: Recognition of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage by active surveillance cultures has been widely debated. Our institution implemented universal nasal screening by polymerase chain reaction (PCR) for MRSA and isolation of screen positive patients in December 2007. Here we present data about the correlation between screen positivity and subsequent development of infection and the impact of isolation on surgical site infection rates. Methods: This was a retrospective, observational study from January 1, 2008, through June 30, 2008, on all inpatient admissions with a nasal MRSA PCR screen. Genotype of 15 MRSA blood isolates was determined utilizing the Diversilab® (bioMérieux, Hazelwood, MO) system. A phenotypic rule was deduced and utilized for analyzing all MRSA clinical isolates. Results: 5375 patients were screened at ≤48 hours following admission. 581 MRSA positive nasal carriers (10.80%) were identified. 496 (85.3%) were asymptomatic MRSA nasal carriers. There were a total of 158 MRSA clinical infections. 85 (14.6%) MRSA nasal carriers had clinical infection. Of the 4794 (89.1%) non-nasally colonized patients, 73 (1.5%) had MRSA clinical infection. MRSA surgical site infection rate remained unchanged during the intervention period. Phenotypic predictive rule inferred 59.8% community-acquired MRSA (CA-MRSA) infections and 40% hospital-acquired MRSA (HA-MRSA) infections. Conclusions: Our study showed a positive correlation between having a nasal screen positivity and subsequent development of infection. Isolation of MRSA screen positive patients alone as an intervention did not reduce the surgical site infection rates. Since most of our isolates are CA-MRSA, our institution is implementing several new interventions to further reduce the incidence of HA-MRSA conditions.

Illness Severity and Work Productivity Loss Among Working Adults With Medically Attended Acute Respiratory Illnesses: US Influenza Vaccine Effectiveness Network 2012–2013

BACKGROUND Influenza causes significant morbidity and mortality, with considerable economic costs, including lost work productivity. Influenza vaccines may reduce the economic burden through primary prevention of influenza and reduction in illness severity. METHODS We examined illness severity and work productivity loss among working adults with medically attended acute respiratory illnesses and compared outcomes for subjects with and without laboratory-confirmed influenza and by influenza vaccination status among subjects with influenza during the 2012-2013 influenza season. RESULTS Illnesses laboratory-confirmed as influenza (ie, cases) were subjectively assessed as more severe than illnesses not caused by influenza (ie, noncases) based on multiple measures, including current health status at study enrollment (≤7 days from illness onset) and current activity and sleep quality status relative to usual. Influenza cases reported missing 45% more work hours (20.5 vs 15.0; P < .001) than noncases and subjectively assessed their work productivity as impeded to a greater degree (6.0 vs 5.4; P < .001). Current health status and current activity relative to usual were subjectively assessed as modestly but significantly better for vaccinated cases compared with unvaccinated cases; however, no significant modifications of sleep quality, missed work hours, or work productivity loss were noted for vaccinated subjects. CONCLUSIONS Influenza illnesses were more severe and resulted in more missed work hours and productivity loss than illnesses not confirmed as influenza. Modest reductions in illness severity for vaccinated cases were observed. These findings highlight the burden of influenza illnesses and illustrate the importance of laboratory confirmation of influenza outcomes in evaluations of vaccine effectiveness.

C-B5-03: Linking Parent and Child Medical Records to Identify Youth at Risk for Familial Hypercholesterolemia

Background Despite consistent recommendations in numerous guidelines sponsored by professional societies, screening youth for familial hypercholesterolemia (FH) and/or those with a family history of premature cardiovascular disease (CVD) identifies only a small percentage of high-risk youth. By linking parent and child data in the virtual data warehouse, we can assess current screening practices, factors that impact screening practices and ultimately strategies aimed at improving childhood screening. Aims the aim of this study is to compare cholesterol testing and screening rates in youth who have at least one parent covered under the same health plan with a history of CVD defined as a history of myocardial infarction, percutaneous coronary artery intervention (PCI) or coronary artery bypass surgery (CABG) and/or a parent with FH established by ICD-9 diagnoses or an abnormal cholesterol level. Methods A cohort of youth who were 2–26 years of age anytime between service dates inclusive of 01/01/2001 and 12/31/2009 and who were covered as insured members under their parents’ health plans within the Scott & White HMO were identified including a subset with any ICD-9 diagnosis code associated with hyperlipidemia. Parent-child linkagages were created using a subscriber_id relationship code and relationship description. The parental cohort with CVD was identified from the CVRN Surveillance study as well as parents who have FH defined as an LDL-C of > 215 mg/dl or a total cholesterol > 300 mg/dl. Results We found that adherence to guidelines for cholesterol screening of youth at a higher risk for premature CHD is no greater than screening rates for children with a lower risk who do not have an affected parent. Moreover, a family history of CHD and hypercholesterolemia is rarely documented in a dependent’s medical record. Conclusions Cost-effective approaches to screening for FH in the pediatric population rely on a parental history of CVD and/or FH. However, this approach does not identify the majority of youth at risk for premature CVD. Universal screening of youth may be warranted.

Influenza Vaccine Effectiveness in the United States During the 2016–2017 Season

BACKGROUND In recent influenza seasons, the effectiveness of inactivated influenza vaccines against circulating A(H3N2) virus has been lower than against A(H1N1)pdm09 and B viruses, even when circulating viruses remained antigenically similar to vaccine components. METHODS During the 2016-2017 influenza season, vaccine effectiveness (VE) across age groups and vaccine types was examined among outpatients with acute respiratory illness at 5 US sites using a test-negative design that compared the odds of vaccination among reverse transcription polymerase chain reaction-confirmed influenza positives and negatives. RESULTS Among 7083 enrollees, 1342 (19%) tested positive for influenza A(H3N2), 648 (9%) were positive for influenza B (including B/Yamagata, n = 577), and 5040 (71%) were influenza negative. Vaccine effectiveness was 40% (95% confidence interval [CI], 32% to 46%) against any influenza virus, 33% (95% CI, 23% to 41%) against influenza A(H3N2) viruses, and 53% (95% CI, 43% to 61%) against influenza B viruses. CONCLUSIONS The 2016-2017 influenza vaccines provided moderate protection against any influenza among outpatients but were less protective against influenza A(H3N2) viruses than B viruses. Approaches to improving effectiveness against A(H3N2) viruses are needed.

Cumulative Incidence Estimates of Medically Attended Seasonal Influenza From 2011–2016 for the Central Texas Baylor Scott & White Health: Temple Population Research Area (BSWH-TPRA)

Acknowledgement Background: Severity and burden of influenza can be estimated with the cumulative incidence of lab-confirmed influenza among medically-attended acute respiratory illnesses (MAARI) during local circulation. Methods: BSWH is one of 5 CDC US Flu Vaccine Effectiveness network sites since 2011. The BSWH-TPRA source population was defined as residents from zip codes within East Bell County, Central Texas (CTX), who have seen a primary care provider for any reason in the past 3 years. We enrolled outpatients with acute respiratory illness of ≤7 days, with cough and tested nasal-throat swabs for influenza A&B by RT-PCR. Vaccination was verified with electronic records. We divided the population into 4 age strata and 2 vaccination statuses. Within each stratum and status, we formed 3 subgroups based on number of MAARIs: (None, 1, and ≥2). Applying proportions observed in the enrollees, we estimated the cumulative incidence of medically-attended seasonal influenza. Results: Table: Cumulative Incidence of Seasonal Influenza in the BSWH-TPRA 2011-12 to 201516.

PS2-50: VDW Data Sources: Scott & White Healthcare

Background The Virtual Data Warehouse (VDW) was created as a mechanism for producing comparable data across sites for purposes of proposing and conducting research. The database is “virtual” in the sense that the data remain at the local sites; there is no multi-site physical database at a centralized center. At the core of the VDW are a series of standardized file definitions. Content areas and data elements that are commonly required for research studies are identified, and data dictionaries are created for each of the content areas, specifying a common format for each of the elements—variable name, label, description, code values, and value labels. Local site programmers have mapped the data elements from their HMO’s data systems into this standardized set of variable definitions, names, and codes, as well as onto standardized SAS file formats. This common structure of the VDW files enables a SAS analyst at one site to write one program to extract and/or analyze data at all participating sites. Methods This poster demonstrates the wide range of data sources used at Scott & White to feed information into our local implementation of the VDW datasets. Results Scott & White local implementation of the VDW contains detailed medical information on Scott & White Health Plan (SWHP), EMR (Electronic Medical Records), Lab Services, Pharmacy Department, State Death Data, State Provider Data, CENSUS Bureau Data and Medical Staff Services Data from year 2001 to present. The VDW tumor data are loaded from the Scott & White Tumor Registry. VDW tables are built and maintained from these different sources within Scott & White. Conclusions The VDW at Scott & White provides an easily employed unified central repository of data from all available source files. This resource enables the sharing of compatible data in multi-site studies, and also improves programming efficiency, accuracy, and completeness for local single site studies by expending resources to link these legacy systems only once.