Girishanthy Krishnarajah

Vaccination Rates among the General Adult Population and High-Risk Groups in the United States

Background In order to adequately assess the effectiveness of vaccination in helping to control vaccine-preventable infectious disease, it is important to identify the adherence and uptake of risk-based recommendations. Methods The current project includes data from five consecutive datasets of the National Health and Wellness Survey (NHWS): 2007 through 2011. The NHWS is an annual, Internet-based health questionnaire, administered to a nationwide sample of adults (aged 18 or older) which included items on vaccination history as well as high-risk group status. Vaccination rates and characteristics of vaccinees were reported descriptively. Logistic regressions were conducted to predict vaccination behavior from sociodemographics and risk-related variables. Results The influenza vaccination rate for all adults 18 years and older has increased significantly from 28.0% to 36.2% from 2007 to 2011 (ps<.05). Compared with those not at high risk (25.1%), all high-risk groups were vaccinated at a higher rate, from 36.8% (pregnant women) to 69.7% (those with renal/kidney disease); however, considerable variability among high-risk groups was observed. Vaccination rates among high-risk groups for other vaccines varied considerably though all were below 50%, with the exception of immunocompromised respondents (57.5% for the hepatitis B vaccine and 52.5% for the pneumococcal vaccine) and the elderly (50.4% for the pneumococcal). Multiple risk factors were associated with increased rate of vaccination for most vaccines. Significant racial/ethnic differences with influenza, hepatitis, and herpes zoster vaccination rates were also observed (ps<.05). Conclusions Rates of influenza vaccination have increased over time. Rates varied by high-risk status, demographics, and vaccine. There was a pattern of modest vaccination rate increases for individuals with multiple risk factors. However, there were relatively low rates of vaccination for most risk-based recommendations and all fell below national goals.

The disease burden of pertussis in adults 50 years old and older in the United States: a retrospective study

BackgroundWhile the incidence of pertussis has increased in adolescents and adults in recent years in the U.S., little is known about the incidence and economic burden of pertussis in older adults. This study provides evidence of the incidence of pertussis and direct medical charges associated with pertussis episodes of care (PEOCs) in adults aged 50 years and older in the U.S.MethodsPEOCs were divided into periods before and after the initial pertussis diagnosis was made (i.e., the index date) to capture any conditions immediately preceding the pertussis diagnosis that may have represented misdiagnoses and subsequent conditions that may have represented sequelae. Data were extracted from IMSs recently acquired SDI databases of longitudinal, patient-level practitioner claims and hospital operational billing records collected from private practitioners and hospitals, respectively, across the U.S. Patients 50 years and older with one or more ICD-9-CM diagnoses for pertussis/whooping cough and/or a laboratory test positive for Bordetella pertussis between 1/1/2006 and 10/31/2010 were eligible for study inclusion. Resource utilization and charges (i.e., unadjudicated claims) associated with the patients physician and hospital care were analyzed. The nationally projected incidence of pertussis was estimated using a subsample of patients with the required data necessary for projection.ResultsEstimated incidence of diagnosed pertussis ranged from 2.1-4.6 cases per 100,000 people across the two age groups (50–64 and [greater than or equal to] 65) during the years 2006 to 2010. The analysis of charges included 5,748 patients [greater than or equal to] 50 years of age with pertussis. Average charges across the entire episode of care were

Cost-Effectiveness of Tdap Vaccination of Adults Aged ≥65 Years in the Prevention of Pertussis in the US: A Dynamic Model of Disease Transmission

1,835 and

Rotavirus vaccine series completion and adherence to vaccination schedules among infants in managed care in the United States

14,428 per patient in the outpatient and inpatient settings, respectively. The average number of outpatient (i.e., private practitioner) visits was 2 per patient in both the pre-index and post-index periods.ConclusionsIn the U.S., the incidence of diagnosed pertussis in adults 50 years and older has increased between 2006 and 2010. Healthcare utilization and charges associated with pertussis are substantial, suggesting the need for additional prevention and control strategies and a higher degree of clinical awareness on the part of health care providers. Additional research regarding pertussis in older populations is needed to substantiate these findings.

Completion and compliance of childhood vaccinations in the United States

Objectives In February 2012, the Advisory Committee on Immunization Practices (ACIP) advised that all adults aged ≥65 years receive a single dose of reduced-antigen-content tetanus, diphtheria, and acellular pertussis (Tdap), expanding on a 2010 recommendation for adults >65 that was limited to those with close contact with infants. We evaluated clinical and economic outcomes of adding Tdap booster of adults aged ≥65 to “baseline” practice [full-strength DTaP administered from 2 months to 4–6 years, and one dose of Tdap at 11–64 years replacing decennial Td booster], using a dynamic model. Methods We constructed a population-level disease transmission model to evaluate the cost-effectiveness of supplementing baseline practice by vaccinating 10% of eligible adults aged ≥65 with Tdap replacing the decennial Td booster. US population effects, including indirect benefits accrued by unvaccinated persons, were estimated during a 1-year period after disease incidence reached a new steady state, with consequences of deaths and long-term pertussis sequelae projected over remaining lifetimes. Model outputs include: cases by severity, encephalopathy, deaths, costs (of vaccination and pertussis care) and quality-adjusted life-years (QALYs) associated with each strategy. Results in terms of incremental cost/QALY gained are presented from payer and societal perspectives. Sensitivity analyses vary key parameters within plausible ranges. Results For the US population, the intervention is expected to prevent >97,000 cases (>4,000 severe and >5,000 among infants) of pertussis annually at steady state. Additional vaccination costs are

Cost-Effectiveness Analysis of Tdap in the Prevention of Pertussis in the Elderly

4.7 million. Net cost savings, including vaccination costs, are

Waning protection following 5 doses of a 3-component diphtheria, tetanus, and acellular pertussis vaccine

47.7 million (societal perspective) and

Public Health Impact of Complete and Incomplete Rotavirus Vaccination among Commercially and Medicaid Insured Children in the United States

44.8 million (payer perspective). From both perspectives, the intervention strategy is dominant (less costly, and more effective by >3,000 QALYs) versus baseline. Results are robust to sensitivity analyses and alternative scenarios. Conclusions Immunization of eligible adults aged ≥65, consistent with the current ACIP recommendation, is cost saving from both payer and societal perspectives.

Incidence and burden of pertussis among infants less than 1 year of age

BACKGROUND Two rotavirus vaccines are currently approved in the United States: 3-dose RotaTeq (RV5; Merck & Co., Inc., Whitehouse Station, NJ, USA) is administered at ages 2, 4, and 6 months; and 2-dose Rotarix (RV1; GlaxoSmithKline, Research Triangle Park, NC, USA) is administered at ages 2 and 4 months. Our objective was to compare rotavirus vaccine series completion and dosing schedule compliance between cohorts of infants who received these vaccines. METHODS Infants aged less than 1 year who initiated a rotavirus vaccine series between 01 January 2009 and 30 June 2009 were identified in US health insurance claims data. Cohorts were formed based on vaccine brand use. Series completion and compliance with the FDA-approved and ACIP-recommended harmonized schedules were analyzed descriptively and a log binomial model was used to estimate the difference in series completion by vaccine brand while adjusting for demographic variables. RESULTS Among infants in the RV1 and RV5 cohorts (N=55,584), 84.3% completed a full series. A greater proportion of the RV1 cohort than the RV5 cohort completed their series (91.0% vs. 83.4%; P<0.001; multivariate-adjusted relative risk 1.07; 95% CI 1.06-1.08). In the RV1 and RV5 cohorts, respectively, 75.0% and 59.5% of infants were fully compliant with the FDA-approved administration schedule for their vaccine (P<0.001); 83.3% and 76.4% of infants were fully compliant with the harmonized schedule (P<0.001). CONCLUSIONS The proportion of infants that completed the series was greater and compliance with respective FDA-approved and harmonized dosing schedules was higher among infants vaccinated with RV1 than among infants who received RV5.

Rotavirus vaccination compliance and completion in a Medicaid infant population.

BACKGROUND The Advisory Committee on Immunization Practices recommends routine childhood vaccination by age 2 years, yet evidence suggests that only 2% to 26% of children receive vaccine doses at age-appropriate times (compliance). The objective of this study was to estimate vaccine completion and compliance rates between birth and age 2 years using recent, nationally representative data. METHODS Using a sample of children aged 24 to 35 months from the 2012 National Immunization Survey (NIS), the present study examined completion and compliance of recommended childhood vaccines. A state-specific examination of vaccine completion and compliance was also conducted. RESULTS An unweighted sample of 11,710 children (weighted to 4.1 million) was selected. Approximately 70% of children completed all doses of six recommended vaccines by 24 months of age. Completion rates varied by antigen, ranging from 68% completing two or three doses of rotavirus vaccine to 92% completing three doses of inactivated poliovirus vaccine. Vaccine completion rates also varied at different measurement periods, with the lowest rates observed at 18 months. Approximately 26% of children received all doses of six recommended vaccines on time. Among the 74% of children who received at least one late dose, 39% had >7 months of undervaccination. Patterns of completion and compliance also varied by geographic region. CONCLUSIONS Completion of individual antigens approached Healthy People 2020 targets. However, overall completion of the recommended vaccine series and compliance with the recommended vaccination dosing schedule were low, indicating few children received vaccines at age-appropriate times. Additional clinical, policy, and educational interventions are needed to increase receipt of vaccines at optimal ages.