Efficacy and safety of a single dose of casirivimab and imdevimab for the prevention of COVID-19 over an 8-month period: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: There is an unmet need for COVID-19 prevention in patient populations who have not mounted or are not expected to mount an adequate immune response to complete COVID-19 vaccination. We previously reported that a single subcutaneous 1200 mg dose of the monoclonal antibody combination casirivimab and imdevimab (CAS + IMD) prevented symptomatic SARS-CoV-2 infections by 81·4% in generally healthy household contacts of SARS-CoV-2-infected individuals over a 1-month efficacy assessment period. Here we present additional results, including the 7-month follow-up period (months 2-8), providing additional insights about the potential for efficacy in pre-exposure prophylaxis settings. METHODS: This was a randomised, double-blind, placebo-controlled trial done in the USA, Romania, and Moldova in 2020-2021, before the emergence of omicron (B.1.1.529) and omicron-lineage variants. Uninfected and unvaccinated household contacts of infected individuals, judged by the investigator to be in good health, were randomly assigned (1:1) to receive 1200 mg CAS + IMD or placebo by subcutaneous injection according to a central randomisation scheme provided by an interactive web response system; randomisation was stratified per site by the test results of a local diagnostic assay for SARS-CoV-2 and age group at baseline. COVID-19 vaccines were prohibited before randomisation, but participants were allowed to receive COVID-19 vaccination during the follow-up period. Participants who developed COVID-19 symptoms during the follow-up period underwent RT-PCR testing. Prespecified endpoints included the proportion of previously uninfected and baseline-seronegative participants (seronegative-modified full analysis set) who had RT-PCR-confirmed COVID-19 in the follow-up period (post-hoc for the timepoints of months 2-5 and 6-8 only) and underwent seroconversion (ie, became seropositive, considered a proxy for any SARS-CoV-2 infections [symptomatic and asymptomatic]; prespecified up to day 57, post-hoc for all timepoints thereafter). We also assessed the incidence of treatment-emergent adverse events. This study is registered with ClinicalTrials.gov, NCT04452318. FINDINGS: From July 13, 2020, to Oct 4, 2021, 2317 participants who were RT-PCR-negative for SARS-CoV-2 were randomly assigned, of whom 1683 (841 assigned to CAS + IMD and 842 assigned to placebo) were seronegative at baseline. During the entirety of the 8-month study, CAS + IMD reduced the risk of COVID-19 by 81·2% (nominal p<0·0001) versus placebo (prespecified analysis). During the 7-month follow-up period, protection was greatest during months 2-5, with a 100% relative risk reduction in COVID-19 (nominal p<0·0001; post-hoc analysis). Efficacy waned during months 6-8 (post-hoc analysis). Seroconversion occurred in 38 (4·5%) of 841 participants in the CAS + IMD group and in 181 (21·5%) of 842 in the placebo group during the 8-month study (79·0% relative risk reduction vs placebo; nominal p<0·0001). Six participants in the placebo group were hospitalised due to COVID-19 versus none who received CAS + IMD. Serious treatment-emergent adverse events (including COVID-19) were reported in 24 (1·7%) of 1439 participants receiving CAS + IMD and in 23 (1·6%) of 1428 receiving placebo. Five deaths were reported, none of which were due to COVID-19 or related to the study drugs. INTERPRETATION: CAS + IMD is not authorised in any US region as of Jan 24, 2022, because data show that CAS + IMD is not active against omicron-lineage variants. In this study, done before the emergence of omicron-lineage variants, a single subcutaneous 1200 mg dose of CAS + IMD protected against COVID-19 for up to 5 months of community exposure to susceptible strains of SARS-CoV-2 in the pre-exposure prophylaxis setting, in addition to the post-exposure prophylaxis setting that was previously shown. FUNDING: Regeneron Pharmaceuticals, F Hoffmann-La Roche, US National Institute of Allergy and Infectious Diseases, US National Institutes of Health.

Effect of Subcutaneous Casirivimab and Imdevimab Antibody Combination vs Placebo on Development of Symptomatic COVID-19 in Early Asymptomatic SARS-CoV-2 Infection: A Randomized Clinical Trial.

Importance: Easy-to-administer anti-SARS-CoV-2 treatments may be used to prevent progression from asymptomatic infection to symptomatic disease and to reduce viral carriage. Objective: To evaluate the effect of combination subcutaneous casirivimab and imdevimab on progression from early asymptomatic SARS-CoV-2 infection to symptomatic COVID-19. Design, Setting, and Participants: Randomized, double-blind, placebo-controlled, phase 3 trial of close household contacts of a SARS-CoV-2-infected index case at 112 sites in the US, Romania, and Moldova enrolled July 13, 2020-January 28, 2021; follow-up ended March 11, 2021. Asymptomatic individuals (aged ≥12 years) were eligible if identified within 96 hours of index case positive test collection. Results from 314 individuals positive on SARS-CoV-2 reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) testing are reported. Interventions: Individuals were randomized 1:1 to receive 1 dose of subcutaneous casirivimab and imdevimab, 1200 mg (600 mg of each; n = 158), or placebo (n = 156). Main Outcomes and Measures: The primary end point was the proportion of seronegative participants who developed symptomatic COVID-19 during the 28-day efficacy assessment period. The key secondary efficacy end points were the number of weeks of symptomatic SARS-CoV-2 infection and the number of weeks of high viral load (>4 log10 copies/mL). Results: Among 314 randomized participants (mean age, 41.0 years; 51.6% women), 310 (99.7%) completed the efficacy assessment period; 204 were asymptomatic and seronegative at baseline and included in the primary efficacy analysis. Subcutaneous casirivimab and imdevimab, 1200 mg, significantly prevented progression to symptomatic disease (29/100 [29.0%] vs 44/104 [42.3%] with placebo; odds ratio, 0.54 [95% CI, 0.30-0.97]; P = .04; absolute risk difference, -13.3% [95% CI, -26.3% to -0.3%]). Casirivimab and imdevimab reduced the number of symptomatic weeks per 1000 participants (895.7 weeks vs 1637.4 weeks with placebo; P = .03), an approximately 5.6-day reduction in symptom duration per symptomatic participant. Treatment with casirivimab and imdevimab also reduced the number of high viral load weeks per 1000 participants (489.8 weeks vs 811.9 weeks with placebo; P = .001). The proportion of participants receiving casirivimab and imdevimab who had 1 or more treatment-emergent adverse event was 33.5% vs 48.1% for placebo, including events related (25.8% vs 39.7%) or not related (11.0% vs 16.0%) to COVID-19. Conclusions and Relevance: Among asymptomatic SARS-CoV-2 RT-qPCR-positive individuals living with an infected household contact, treatment with subcutaneous casirivimab and imdevimab antibody combination vs placebo significantly reduced the incidence of symptomatic COVID-19 over 28 days. Trial Registration: ClinicalTrials.gov Identifier: NCT04452318.

Subcutaneous REGEN-COV Antibody Combination to Prevent Covid-19.

BACKGROUND: REGEN-COV (previously known as REGN-COV2), a combination of the monoclonal antibodies casirivimab and imdevimab, has been shown to markedly reduce the risk of hospitalization or death among high-risk persons with coronavirus disease 2019 (Covid-19). Whether subcutaneous REGEN-COV prevents severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and subsequent Covid-19 in persons at high risk for infection because of household exposure to a person with SARS-CoV-2 infection is unknown. METHODS: We randomly assigned, in a 1:1 ratio, participants (≥12 years of age) who were enrolled within 96 hours after a household contact received a diagnosis of SARS-CoV-2 infection to receive a total dose of 1200 mg of REGEN-COV or matching placebo administered by means of subcutaneous injection. At the time of randomization, participants were stratified according to the results of the local diagnostic assay for SARS-CoV-2 and according to age. The primary efficacy end point was the development of symptomatic SARS-CoV-2 infection through day 28 in participants who did not have SARS-CoV-2 infection (as measured by reverse-transcriptase-quantitative polymerase-chain-reaction assay) or previous immunity (seronegativity). RESULTS: Symptomatic SARS-CoV-2 infection developed in 11 of 753 participants in the REGEN-COV group (1.5%) and in 59 of 752 participants in the placebo group (7.8%) (relative risk reduction [1 minus the relative risk], 81.4%; P<0.001). In weeks 2 to 4, a total of 2 of 753 participants in the REGEN-COV group (0.3%) and 27 of 752 participants in the placebo group (3.6%) had symptomatic SARS-CoV-2 infection (relative risk reduction, 92.6%). REGEN-COV also prevented symptomatic and asymptomatic infections overall (relative risk reduction, 66.4%). Among symptomatic infected participants, the median time to resolution of symptoms was 2 weeks shorter with REGEN-COV than with placebo (1.2 weeks and 3.2 weeks, respectively), and the duration of a high viral load (>104 copies per milliliter) was shorter (0.4 weeks and 1.3 weeks, respectively). No dose-limiting toxic effects of REGEN-COV were noted. CONCLUSIONS: Subcutaneous REGEN-COV prevented symptomatic Covid-19 and asymptomatic SARS-CoV-2 infection in previously uninfected household contacts of infected persons. Among the participants who became infected, REGEN-COV reduced the duration of symptomatic disease and the duration of a high viral load. (Funded by Regeneron Pharmaceuticals and others; ClinicalTrials.gov number, NCT04452318.).

Subcutaneous REGEN-COV Antibody Combination in Early Asymptomatic SARS-CoV-2 Infection: A Randomized Clinical Trial.

IMPORTANCE: Easy-to-administer antiviral treatments may be used to prevent progression from asymptomatic infection to COVID-19 and to reduce viral carriage. OBJECTIVE: Evaluate the efficacy and safety of subcutaneous casirivimab and imdevimab antibody combination (REGEN-COV) to prevent progression from early asymptomatic SARS-CoV-2 infection to COVID-19. DESIGN: Randomized, double-blind, placebo-controlled, phase 3 study that enrolled asymptomatic close contacts living with a SARS-CoV-2-infected household member (index case). Participants who were SARS-CoV-2 RT-qPCR-positive at baseline were included in the analysis reported here. SETTING: Multicenter trial conducted at 112 sites in the United States, Romania, and Moldova. PARTICIPANTS: Asymptomatic individuals ≥12 years of age were eligible if identified within 96 hours of collection of the index case's positive SARS-CoV-2 test sample. INTERVENTIONS: A total of 314 asymptomatic, SARS-CoV-2 RT-qPCR-positive individuals living with an infected household contact were randomized 1:1 to receive a single dose of subcutaneous REGEN-COV 1200mg (n=158) or placebo (n=156). MAIN OUTCOMES AND MEASURES: The primary endpoint was the proportion of participants who developed symptomatic COVID-19 during the 28-day efficacy assessment period. The key secondary efficacy endpoints were the number of weeks of symptomatic SARS-CoV-2 infection and the number of weeks of high viral load (>4 log10 copies/mL). Safety was assessed in all treated participants. RESULTS: Subcutaneous REGEN-COV 1200mg significantly prevented progression from asymptomatic to symptomatic disease compared with placebo (31.5% relative risk reduction; 29/100 [29.0%] vs 44/104 [42.3%], respectively; P=.0380). REGEN-COV reduced the overall population burden of high-viral load weeks (39.7% reduction vs placebo; 48 vs 82 total weeks; P=.0010) and of symptomatic weeks (45.3% reduction vs placebo; 89.6 vs 170.3 total weeks; P=.0273), the latter corresponding to an approximately 5.6-day reduction in symptom duration per symptomatic participant. Six placebo-treated participants had a COVID-19-related hospitalization or ER visit versus none for those receiving REGEN-COV. The proportion of participants receiving placebo who had ≥1 treatment-emergent adverse events was 48.1% compared with 33.5% for those receiving REGEN-COV, including events related (39.7% vs 25.8%, respectively) or not related (16.0% vs 11.0%, respectively) to COVID-19. CONCLUSIONS AND RELEVANCE: Subcutaneous REGEN-COV 1200mg prevented progression from asymptomatic SARS-CoV-2 infection to COVID-19, reduced the duration of high viral load and symptoms, and was well tolerated. TRIAL REGISTRATION: ClinicalTrials.gov Identifier, NCT04452318.

Subcutaneous REGEN-COV Antibody Combination for Covid-19 Prevention.

Background: Casirivimab and imdevimab (REGEN-COV™) markedly reduces risk of hospitalization or death in high-risk individuals with Covid-19. Here we explore the possibility that subcutaneous REGEN-COV prevents SARS-CoV-2 infection and subsequent Covid-19 in individuals at high risk of contracting SARS-CoV-2 by close exposure in a household with a documented SARS-CoV-2-infected individual. Methods: Individuals ≥12 years were enrolled within 96 hours of a household contact being diagnosed with SARS-CoV-2 and randomized 1:1 to receive 1200 mg REGEN-COV or placebo via subcutaneous injection. The primary efficacy endpoint was the proportion of participants without evidence of infection (SARS-CoV-2 RT-qPCR-negative) or prior immunity (seronegative) who subsequently developed symptomatic SARS-CoV-2 infection during a 28-day efficacy assessment period. Results: Subcutaneous REGEN-COV significantly prevented symptomatic SARS-CoV-2 infection compared with placebo (81.4% risk reduction; 11/753 [1.5%] vs. 59/752 [7.8%], respectively; P<0.0001), with 92.6% risk reduction after the first week (2/753 [0.3%] vs. 27/752 [3.6%], respectively). REGEN-COV also prevented overall infections, either symptomatic or asymptomatic (66.4% risk reduction). Among infected participants, the median time to resolution of symptoms was 2 weeks shorter with REGEN-COV vs. placebo (1.2 vs. 3.2 weeks, respectively), and the duration of time with high viral load (>104 copies/mL) was lower (0.4 vs. 1.3 weeks, respectively). REGEN-COV was generally well tolerated. Conclusions: Administration of subcutaneous REGEN-COV prevented symptomatic Covid-19 and asymptomatic SARS-CoV-2 infection in uninfected household contacts of infected individuals. Among individuals who became infected, REGEN-COV reduced the duration of symptomatic disease, decreased maximal viral load, and reduced the duration of detectable virus.(ClinicalTrials.gov number, NCT04452318.).

A National Implementation Project to Prevent Catheter-Associated Urinary Tract Infection in Nursing Home Residents.

Importance: Catheter-associated urinary tract infection (UTI) in nursing home residents is a common cause of sepsis, hospital admission, and antimicrobial use leading to colonization with multidrug-resistant organisms. Objective: To develop, implement, and evaluate an intervention to reduce catheter-associated UTI. Design, Setting, and Participants: A large-scale prospective implementation project was conducted in community-based nursing homes participating in the Agency for Healthcare Research and Quality Safety Program for Long-Term Care. Nursing homes across 48 states, Washington DC, and Puerto Rico participated. Implementation of the project was conducted between March 1, 2014, and August 31, 2016. Interventions: The project was implemented over 12-month cohorts and included a technical bundle: catheter removal, aseptic insertion, using regular assessments, training for catheter care, and incontinence care planning, as well as a socioadaptive bundle emphasizing leadership, resident and family engagement, and effective communication. Main Outcomes and Measures: Urinary catheter use and catheter-associated UTI rates using National Healthcare Safety Network definitions were collected. Facility-level urine culture order rates were also obtained. Random-effects negative binomial regression models were used to examine changes in catheter-associated UTI, catheter utilization, and urine cultures and adjusted for covariates including ownership, bed size, provision of subacute care, 5-star rating, presence of an infection control committee, and an infection preventionist. Results: In 4 cohorts over 30 months, 568 community-based nursing homes were recruited; 404 met inclusion criteria for analysis. The unadjusted catheter-associated UTI rates decreased from 6.78 to 2.63 infections per 1000 catheter-days. With use of the regression model and adjustment for facility characteristics, the rates decreased from 6.42 to 3.33 (incidence rate ratio [IRR], 0.46; 95% CI, 0.36-0.58; P < .001). Catheter utilization was 4.5% at baseline and 4.9% at the end of the project. Catheter utilization remained unchanged (4.50 at baseline, 4.45 at conclusion of project; IRR, 0.95; 95% CI, 0.88-1.03; P = .26) in adjusted analyses. The number of urine cultures ordered for all residents decreased from 3.49 per 1000 resident-days to 3.08 per 1000 resident-days. Similarly, after adjustment, the rates were shown to decrease from 3.52 to 3.09 (IRR, 0.85; 95% CI, 0.77-0.94; P = .001). Conclusions and Relevance: In a large-scale, national implementation project involving community-based nursing homes, combined technical and socioadaptive catheter-associated UTI prevention interventions successfully reduced the incidence of catheter-associated UTIs.

Venous thromboembolism incidence, recurrence, and mortality based on Women's Health Initiative data and Medicare claims.

INTRODUCTION: Our objective was to compare Medicare claims to physician review and adjudication of medical records for identifying venous thromboembolism (VTE), and to assess VTE incidence, recurrence, and mortality in a large national cohort of post-menopausal women followed up to 19years. MATERIALS AND METHODS: We used detailed clinical data from the Women's Health Initiative (WHI) linked to Medicare claims. Agreement between data sources was evaluated among 16,003 women during 1993-2010. A claims-based definition was selected to analyze VTE occurrence and impact among 71,267 women during 1993-2012. RESULTS: Our VTE definition had 83% sensitivity. Positive predictive value was 69% when all records were included, and 94% after limiting Medicare records to those with a WHI hospitalization adjudicated. Annualized VTE incidence was 4.06/1000person-years (PY), recurrence was 5.30/100PY, and both rates varied by race/ethnicity. Post-VTE mortality within 1year was 22.49% from all causes, including 1.01% from pulmonary embolism, 10.40% from cancer, and 11.08% from other causes. Cancer-related VTE compared to non-cancer VTE had significantly (p<0.001) higher recurrence (9.86/100PY vs. 4.43/100PY) and mortality from all causes (45.89% vs. 12.28%), but not from pulmonary embolism (0.40% vs. 1.27%). CONCLUSIONS: Medicare claims compared reasonably well to physician adjudication. The combined data sources provided new insights about VTE burden and prognosis in older women.

Pregnancy as a Window to Future Cardiovascular Health: Design and Implementation of the nuMoM2b Heart Health Study.

The National Institute of Child Health and Human Development's Nulliparous Pregnancy Outcomes Study-Monitoring Mothers-to-Be (nuMoM2b) Heart Health Study (HHS) was designed to investigate the relationships between adverse pregnancy outcomes and modifiable risk factors for cardiovascular disease. The ongoing nuMoM2b-HHS, which started in 2013, is a prospective follow-up of the nuMoM2b cohort, which included 10,038 women recruited between 2010 and 2013 from 8 centers across the United States who were initially observed over the course of their first pregnancies. In this report, we detail the design and study procedures of the nuMoM2b-HHS. Women in the pregnancy cohort who consented to be contacted for participation in future studies were approached at 6-month intervals to ascertain health information and to maintain ongoing contact. Two to 5 years after completion of the pregnancy documented in the nuMoM2b, women in the nuMoM2b-HHS were invited to an in-person study visit. During this visit, they completed psychosocial and medical history questionnaires and had clinical measurements and biological specimens obtained. A subcohort of participants who had objective assessments of sleep-disordered breathing during pregnancy were asked to repeat this investigation. This unique prospective observational study includes a large, geographically and ethnically diverse cohort, rich depth of phenotypic information about adverse pregnancy outcomes, and clinical data and biospecimens from early in the index pregnancy onward. Data obtained from this cohort will provide mechanistic and clinical insights into how data on a first pregnancy can provide information about the potential development of subsequent risk factors for cardiovascular disease.

Evaluation of Medicare claims data to ascertain peripheral vascular events in the Women's Health Initiative.

OBJECTIVE: Capturing long-term outcomes from large clinical databases by use of claims data is a potential strategy for improving efficiency while reducing study costs. We sought to compare the use of Medicare data with data from the Women's Health Initiative (WHI) to determine peripheral vascular events, as defined by the WHI study design. METHODS: We studied participants from the WHI with both adjudicated outcomes and links to Medicare enrollment and utilization data through 2007. Outcomes of interest included hospitalizations for treatment of abdominal aortic aneurysm (AAA), lower extremity peripheral artery disease (LE PAD), and carotid artery stenosis (CAS). Events determined by WHI adjudication were compared with events defined by coding algorithms using diagnosis and procedure codes from Medicare data with a pilot data set and then validated with a test data set. We assessed agreement by a κ statistic and evaluated reasons for disagreement. RESULTS: In the pilot set, records from 50,511 participants were analyzed. Agreement between the Centers for Medicare and Medicaid Services and WHI for admissions with a diagnosis but no treatment procedures for vascular conditions was poor (κ, 0.02-0.18). On the basis of WHI outcome data collection, vascular treatment procedures occurred in 29 participants for AAA, 204 for LE PAD events, and 281 for CAS. Medicare hospital claims recorded 41 treatments for AAA, 255 for LE PAD, and 317 for CAS. For participants with a Centers for Medicare and Medicaid Services-captured vascular procedure and a record adjudicated by WHI, κ values for treatment procedures were 0.81 for AAA, 0.77 for PAD, and 0.93 for CAS. For vascular procedures identified by WHI but not by Medicare hospital data (n = 82), 55% were captured by Medicare physician claims. Conversely, for treatments identified by Medicare hospital data but not captured by WHI adjudication (n = 57), 74% had physician claims consistent with the procedure. Fifteen participants with AAA or LE PAD procedures in hospital claims had medical records available for review, and nine of these had definitive documentation of procedures that were not captured by the WHI adjudication process. Estimated positive predictive value of Medicare data was 91% to 94% for AAA, 92% to 95% for LE PAD, and 94% to 99% for CAS. Available test set data (n = 50,253) yielded generally similar results with κ of 0.77 for AAA, 0.79 for LE PAD, and 0.94 for CAS. CONCLUSIONS: Medicare data appear useful for identifying vascular treatment procedures for WHI participants. Medicare hospital claims identify more procedures than WHI does, with high positive predictive value, but also may not capture some procedures identified in WHI.

Comparison of Medicare claims versus physician adjudication for identifying stroke outcomes in the Women's Health Initiative.

BACKGROUND AND PURPOSE: Many studies use medical record review for ascertaining outcomes. One large, longitudinal study, the Women's Health Initiative (WHI), ascertains strokes using participant self-report and subsequent physician review of medical records. This is resource-intensive. Herein, we assess whether Medicare data can reliably assess stroke events in the WHI. METHODS: Subjects were WHI participants with fee-for-service Medicare. Four stroke definitions were created for Medicare data using discharge diagnoses in hospitalization claims: definition 1, stroke codes in any position; definition 2, primary position stroke codes; and definitions 3 and 4, hemorrhagic and ischemic stroke codes, respectively. WHI data were randomly split into training (50%) and test sets. A concordance matrix was used to examine the agreement between WHI and Medicare stroke diagnosis. A WHI stroke and a Medicare stroke were considered a match if they occurred within ±7 days of each other. Refined analyses excluded Medicare events when medical records were unavailable for comparison. RESULTS: Training data consisted of 24 428 randomly selected participants. There were 577 WHI strokes and 557 Medicare strokes using definition 1. Of these, 478 were a match. With regard to algorithm performance, specificity was 99.7%, negative predictive value was 99.7%, sensitivity was 82.8%, positive predictive value was 85.8%, and κ=0.84. Performance was similar for test data. Whereas specificity and negative predictive value exceeded 99%, sensitivity ranged from 75% to 88% and positive predictive value ranged from 80% to 90% across stroke definitions. CONCLUSIONS: Medicare data seem useful for population-based stroke research; however, performance characteristics depend on the definition selected.

Use of Medicare data to identify coronary heart disease outcomes in the Women's Health Initiative.

BACKGROUND: Data collected as part of routine clinical practice could be used to detect cardiovascular outcomes in pragmatic clinical trials or clinical registry studies. The reliability of claims data for documenting outcomes is unknown. METHODS AND RESULTS: We linked records of Women's Health Initiative (WHI) participants aged ≥65 years to Medicare claims data and compared hospitalizations that had diagnosis codes for acute myocardial infarction or coronary revascularization with WHI outcomes adjudicated by study physicians. We then compared the hazard ratios for active versus placebo hormone therapy based solely on WHI-adjudicated events with corresponding hazard ratios based solely on claims data for the same hormone trial participants. Agreement between WHI-adjudicated outcomes and Medicare claims was good for the diagnosis of myocardial infarction (κ, 0.71-0.74) and excellent for coronary revascularization (κ, 0.88-0.91). The hormone:placebo hazard ratio for clinical myocardial infarction was 1.31 (95% confidence interval, 1.03-1.67) based on WHI outcomes and 1.29 (95% confidence interval, 1.00-1.68) based on Medicare data. The hazard ratio for coronary revascularization was 1.09 (95% confidence interval, 0.88-1.35) based on WHI outcomes and 1.10 (95% confidence interval, 0.89-1.35) based on Medicare data. The differences between hazard ratios derived from WHI and Medicare data were not significant in 1000 bootstrap replications. CONCLUSIONS: Medicare claims may provide useful data on coronary heart disease outcomes among patients aged ≥65 years in clinical research studies. CLINICAL TRIALS REGISTRATION INFORMATION: URL: www.clinicaltrials.gov. Unique identifier: NCT00000611.

Assessment of tissue allograft safety monitoring with administrative healthcare databases: a pilot project using Medicare data.

Assess whether Medicare data are useful for monitoring tissue allograft safety and utilization. We used health care claims (billing) data from 2007 for 35 million fee-for-service Medicare beneficiaries, a predominantly elderly population. Using search terms for transplant-related procedures, we generated lists of ICD-9-CM and CPT(®) codes and assessed the frequency of selected allograft procedures. Step 1 used inpatient data and ICD-9-CM procedure codes. Step 2 added non-institutional provider (e.g., physician) claims, outpatient institutional claims, and CPT codes. We assembled preliminary lists of diagnosis codes for infections after selected allograft procedures. Many ICD-9-CM codes were ambiguous as to whether the procedure involved an allograft. Among 1.3 million persons with a procedure ascertained using the list of ICD-9-CM codes, only 1,886 claims clearly involved an allograft. CPT codes enabled better ascertainment of some allograft procedures (over 17,000 persons had corneal transplants and over 2,700 had allograft skin transplants). For spinal fusion procedures, CPT codes improved specificity for allografts; of nearly 100,000 patients with ICD-9-CM codes for spinal fusions, more than 34,000 had CPT codes indicating allograft use. Monitoring infrequent events (infections) after infrequent exposures (tissue allografts) requires large study populations. A strength of the large Medicare databases is the substantial number of certain allograft procedures. Limitations include lack of clinical detail and donor information. Medicare data can potentially augment passive reporting systems and may be useful for monitoring tissue allograft safety and utilization where codes clearly identify allograft use and coding algorithms can effectively screen for infections.

Chart-confirmed guillain-barre syndrome after 2009 H1N1 influenza vaccination among the Medicare population, 2009-2010.

Given the increased risk of Guillain-Barré Syndrome (GBS) found with the 1976 swine influenza vaccine, both active surveillance and end-of-season analyses on chart-confirmed cases were performed across multiple US vaccine safety monitoring systems, including the Medicare system, to evaluate the association of GBS after 2009 monovalent H1N1 influenza vaccination. Medically reviewed cases consisted of H1N1-vaccinated Medicare beneficiaries who were hospitalized for GBS. These cases were then classified by using Brighton Collaboration diagnostic criteria. Thirty-one persons had Brighton level 1, 2, or 3 GBS or Fisher Syndrome, with symptom onset 1-119 days after vaccination. Self-controlled risk interval analyses estimated GBS risk within the 6-week period immediately following H1N1 vaccination compared with a later control period, with additional adjustment for seasonality. Our results showed an elevated risk of GBS with 2009 monovalent H1N1 vaccination (incidence rate ratio = 2.41, 95% confidence interval: 1.14, 5.11; attributable risk = 2.84 per million doses administered, 95% confidence interval: 0.21, 5.48). This observed risk was slightly higher than that seen with previous seasonal influenza vaccines; however, additional results that used a stricter case definition (Brighton level 1 or 2) were not statistically significant, and our ability to account for preceding respiratory/gastrointestinal illness was limited. Furthermore, the observed risk was substantially lower than that seen with the 1976 swine influenza vaccine.

Association between Guillain-Barré syndrome and influenza A (H1N1) 2009 monovalent inactivated vaccines in the USA: a meta-analysis.

BACKGROUND: The influenza A (H1N1) 2009 monovalent vaccination programme was the largest mass vaccination initiative in recent US history. Commensurate with the size and scope of the vaccination programme, a project to monitor vaccine adverse events was undertaken, the most comprehensive safety surveillance agenda in the USA to date. The adverse event monitoring project identified an increased risk of Guillain-Barré syndrome after vaccination; however, some individual variability in results was noted. Guillain-Barré syndrome is a rare but serious health disorder in which a person's own immune system damages their nerve cells, causing muscle weakness, sometimes paralysis, and infrequently death. We did a meta-analysis of data from the adverse event monitoring project to ascertain whether influenza A (H1N1) 2009 monovalent inactivated vaccines used in the USA increased the risk of Guillain-Barré syndrome. METHODS: Data were obtained from six adverse event monitoring systems. About 23 million vaccinated people were included in the analysis. The primary analysis entailed calculation of incidence rate ratios and attributable risks of excess cases of Guillain-Barré syndrome per million vaccinations. We used a self-controlled risk-interval design. FINDINGS: Influenza A (H1N1) 2009 monovalent inactivated vaccines were associated with a small increased risk of Guillain-Barré syndrome (incidence rate ratio 2·35, 95% CI 1·42-4·01, p=0·0003). This finding translated to about 1·6 excess cases of Guillain-Barré syndrome per million people vaccinated. INTERPRETATION: The modest risk of Guillain-Barré syndrome attributed to vaccination is consistent with previous estimates of the disorder after seasonal influenza vaccination. A risk of this small magnitude would be difficult to capture during routine seasonal influenza vaccine programmes, which have extensive, but comparatively less, safety monitoring. In view of the morbidity and mortality caused by 2009 H1N1 influenza and the effectiveness of the vaccine, clinicians, policy makers, and those eligible for vaccination should be assured that the benefits of inactivated pandemic vaccines greatly outweigh the risks. FUNDING: US Federal Government.

Surveillance for Guillain-Barré syndrome after influenza vaccination among the Medicare population, 2009-2010.

OBJECTIVES: We implemented active surveillance for Guillain-Barré syndrome (GBS) following seasonal or H1N1 influenza vaccination among the Medicare population during the 2009-2010 influenza season. METHODS: We used weekly Medicare claims data to monitor vaccinations and subsequent hospitalizations with principal diagnosis code for GBS within 42 days. Group sequential testing assessed whether the observed GBS rate exceeded a critical limit based on the expected rate from 5 previous years adjusted for claims delay. We evaluated the lag between date of service and date of claims availability and used it for adjustment. RESULTS: By July 30, 2010 (after 26 interim surveillance tests), 14.0 million seasonal and 3.3 million H1N1 vaccinations had accrued. Taking into account claims delay appropriately lowered the critical limit during early monitoring. The observed GBS rate was below the critical limit throughout the surveillance. CONCLUSIONS: Medicare data contributed rapid safety monitoring among millions of 2009-2010 influenza vaccine recipients. Adjustment for claims delay facilitates early detection of potential safety issues. Although limited by lack of medical record review to confirm cases, this claims-based surveillance did not indicate a statistically significant elevated GBS rate following seasonal or H1N1 influenza vaccination.

Babesiosis among elderly Medicare beneficiaries, United States, 2006-2008.

We used administrative databases to assess babesiosis among elderly persons in the United States by year, sex, age, race, state of residence, and diagnosis months during 2006-2008. The highest babesiosis rates were in Connecticut, Rhode Island, New York, and Massachusetts, and findings suggested babesiosis expansion to other states.

Evaluation of Guillain-Barré Syndrome among recipients of influenza vaccine in 2000 and 2001.

BACKGROUND: The 1976-1977 swine influenza vaccine was associated with an elevated risk of Guillain-Barré Syndrome (GBS), especially within 6 weeks after vaccination. A 2004 IOM report concluded that evidence was inadequate to accept or reject a causal relationship between subsequent influenza vaccine formulations and GBS. Studies published after the IOM report have been limited by passively reported data or lack of validation of coded diagnoses. PURPOSE: To evaluate whether influenza vaccine is associated with GBS. METHODS: Controlled observational study using national data from the Medicare program, which ensures a predominantly elderly population. People included had a Medicare claim for influenza vaccination during September-December in 2000 or 2001. Medical records were reviewed to classify definite, probable, or possible GBS (or not a case) using a standardized case definition. In a risk interval design, the incidence rate of GBS during Weeks 0-6 after vaccination (exposed period) was compared to Weeks 9-14 after vaccination (comparison period). Data collection occurred during 2003-2007, and analysis was conducted during 2007-2009. RESULTS: Primary analysis included 22.2 million vaccinees, among whom 164 definite or probable GBS cases with onset during Weeks 0-6 or 9-14 were identified. The incidence rate ratio (IRR [95% CIs]) based on the GBS rate in the vaccine-exposed versus comparison periods, was 1.04 (0.76, 1.43) for combined years; 0.86 (0.52, 1.41) among people vaccinated in 2000; and 1.21 (0.79, 1.86) among people vaccinated in 2001. Secondary analysis additionally included 74 possible GBS cases; results were similar. CONCLUSIONS: Overall, the results do not support an association between influenza vaccine receipt and GBS among the elderly for the years studied (2000-2001 and 2001-2002 formulations).

Outpatient urticaria diagnosis codes have limited predictive value for same-day influenza vaccine adverse event detection.

OBJECTIVES: To assess the predictive value of claims-based outpatient urticaria diagnosis codes to identify potential vaccine-related adverse events (AEs) when recorded on the same day as influenza vaccination. STUDY DESIGN AND SETTING: Health plan members with outpatient claims for influenza vaccination and urticaria on the same day between October 1, 2002, and December 31, 2007, were eligible for inclusion. Electronic medical records (EMRs) for 50 eligible patients with the most recent visits of interest occurring at a large group practice were sampled for review. RESULTS: EMRs were available and reviewed for 42 of 50 patients. An influenza vaccination was confirmed in all reviewed medical charts. Urticaria occurring on the day of influenza vaccination was confirmed for 40% of participants (17/42); 3 confirmed urticaria diagnoses were potential AEs and 14 urticaria events occurred before vaccination. Among those with unconfirmed diagnoses, 17 had no evidence of urticaria on physical examination on the day of interest (4 had evidence of a nonurticarial rash and 13 had no evidence of rash on examination) and 8 had insufficient information to make a clinical determination. CONCLUSION: Outpatient diagnosis codes for urticaria found in health insurance claims data are limited in their predictive value to identify same-day vaccine AEs.

Death and serious illness following influenza vaccination: a multidisciplinary investigation.

PURPOSE: To evaluate a possible association between influenza vaccination and four deaths and four serious illnesses among 114 recent influenza vaccinees in a long-term care facility (LTCF) and two deaths from a nearby physician's office. All had received vaccine from the same lot (Lot A). METHODS: Field investigation including (1) a retrospective cohort study among LTCF residents who received Lot A or other influenza vaccine, (2) review of medical records of cases of death or serious illness, (3) active surveillance of deaths among 1500 community based Lot A vaccinees and (4) laboratory testing of vaccine from available Lot A vials. RESULTS: Medical record reviews showed no common clinical syndrome or cause of death. Laboratory testing of Lot A samples revealed no evidence of tampering and no differences compared to an unrelated lot. The risk of death or hospitalization was not significantly different between persons who received Lot A versus a comparison lot, Lot B (incidence rate ratio (IRR) = 0.9, 95%CI = 0.3-3.3). CONCLUSIONS: There was no clinical or biological evidence pointing to inherent vaccine safety issues, nor was there a detectable increased risk of death or hospitalization among persons vaccinated with Lot A. Lot specific clustering of adverse events (AEs) may reflect medical events causally unrelated to vaccination. Rapid investigations of potential AEs are important to ensure vaccine safety and to maintain public and healthcare provider confidence in vaccines.