Immunization, Antibiotic Use, and Pneumococcal Colonization Over a 15-Year Period.

BACKGROUND: Rates of invasive pneumococcal disease have declined since widespread introduction of pneumococcal conjugate vaccines (PCVs) in the United States. We evaluated the impact of immunization status and recent antibiotic use on an individual child's risk of colonization. METHODS: This study extends previously reported data from children <7 years of age seen for well child or acute care visits in Massachusetts communities. Nasopharyngeal swabs were collected during 6 surveillance seasons from 2000 to 2014. Parent surveys and medical record reviews confirmed immunization status and recent antibiotic use. We estimated the proportions of children colonized with PCV7-included, additional PCV13-included, and non-PCV13 serotypes. Risk factors for colonization with additional PCV13-included and non-PCV13 serotypes were assessed by using generalized linear mixed models adjusted for clustering by community. RESULTS: Among 6537 children, 19A emerged as the predominant serotype in 2004, with substantial reductions in 2014. Among non-PCV serotypes, 15B/C, 35B, 23B, 11A, and 23A were most common in 2014. We observed greater odds for both additional PCV13 and non-PCV13 colonization in younger children, those with more child care exposure, and those with a concomitant respiratory tract infection. Adjusted odds for additional PCV13 colonization was lower (odds ratio 0.48 [95% confidence interval 0.31-0.75]) among children up-to-date for PCV13 vaccines. Recent antibiotic use was associated with higher odds of additional PCV13 colonization but substantially lower odds of non-PCV13 colonization. CONCLUSIONS: Despite the success of pneumococcal vaccines in reducing colonization and disease due to targeted serotypes, ongoing community-based surveillance will be critical to evaluate the impact of interventions on pneumococcal colonization and disease.

Impact of Hospital Operating Margin on Central Line-Associated Bloodstream Infections Following Medicare's Hospital-Acquired Conditions Payment Policy.

In October 2008, Medicare ceased additional payment for hospital-acquired conditions not present on admission. We evaluated the policy's differential impact in hospitals with high vs low operating margins. Medicare's payment policy may have had an impact on reducing central line-associated bloodstream infections in hospitals with low operating margins. Infect. Control Hosp. Epidemiol. 2015;37(1):100-103.

Pharmacogenomic test that predicts response to inhaled corticosteroids in adults with asthma likely to be cost-saving.

AIM: To identify the clinical and economic circumstances under which a pharmacogenomic test that predicts response to inhaled corticosteroids might be a cost-effective option for individuals with asthma. MATERIALS & METHODS: We synthesized published data on clinical and economic outcomes to project 10-year costs, quality-adjusted life-years and cost-effectiveness of pharmacogenomic testing for inhaled corticosteroid response. We assumed the pharmacogenomic test cost was $500 with a sensitivity and specificity of 84 and 98%, respectively. These were varied in sensitivity analyses. RESULTS: Both strategies, pharmacogenomic testing for inhaled corticosteroid response and no testing conferred 7.1 quality-adjusted life-years. Compared with no testing, pharmacogenomic testing costs less. CONCLUSION: Pharmacogenomic testing for asthma is cost-saving and noninferior in improving health. Original submitted 19 November 2014; Revision submitted 23 February 2015.

Impact of Medicare's Hospital-Acquired Condition policy on infections in safety net and non-safety net hospitals.

BACKGROUND: Policymakers may wish to align healthcare payment and quality of care while minimizing unintended consequences, particularly for safety net hospitals. OBJECTIVE: To determine whether the 2008 Centers for Medicare and Medicaid Services Hospital-Acquired Conditions policy had a differential impact on targeted healthcare-associated infection rates in safety net compared with non-safety net hospitals. DESIGN: Interrupted time-series design. SETTING AND PARTICIPANTS: Nonfederal acute care hospitals that reported central line-associated bloodstream infection and ventilator-associated pneumonia rates to the Centers for Disease Control and Prevention's National Health Safety Network from July 1, 2007, through December 31, 2013. RESULTS: We did not observe changes in the slope of targeted infection rates in the postpolicy period compared with the prepolicy period for either safety net (postpolicy vs prepolicy ratio, 0.96 [95% CI, 0.84-1.09]) or non-safety net (0.99 [0.90-1.10]) hospitals. Controlling for prepolicy secular trends, we did not detect differences in an immediate change at the time of the policy between safety net and non-safety net hospitals (P for 2-way interaction, .87). CONCLUSIONS: The Centers for Medicare and Medicaid Services Hospital-Acquired Conditions policy did not have an impact, either positive or negative, on already declining rates of central line-associated bloodstream infection in safety net or non-safety net hospitals. Continued evaluations of the broad impact of payment policies on safety net hospitals will remain important as the use of financial incentives and penalties continues to expand in the United States.

Pharmacogenomic test that predicts response to ß2-agonists in adults with asthma is cost effective.

BACKGROUND: Pharmacogenomic tests that predict which asthma patients are likely to respond to ß2-agonists hold promise to improve care for asthma. OBJECTIVE: To identify the clinical and economic circumstances under which a pharmacogenomic test that predicts response to ß2-agonists might or might not be an appropriate, cost-effective option. METHODS: We synthesized published data on clinical and economic outcomes in adults 18-35 to project 10-year costs, quality-adjusted life years and cost-effectiveness of pharmacogenomic testing for ß2-agonist response. RESULTS: Pharmacogenomic testing for ß2-agonist response conferred a cost-effectiveness ratio of $13,700 per quality-adjusted life year gained compared with no testing. CONCLUSION: Pharmacogenomic testing for ß2-agonist response in individuals with asthma is potentially cost effective and should be pursued by test developers.

Guillain-Barré Syndrome, Influenza Vaccination, and Antecedent Respiratory and Gastrointestinal Infections: A Case-Centered Analysis in the Vaccine Safety Datalink, 2009-2011.

BACKGROUND: Guillain-Barré Syndrome (GBS) can be triggered by gastrointestinal or respiratory infections, including influenza. During the 2009 influenza A (H1N1) pandemic in the United States, monovalent inactivated influenza vaccine (MIV) availability coincided with high rates of wildtype influenza infections. Several prior studies suggested an elevated GBS risk following MIV, but adjustment for antecedent infection was limited. METHODS: We identified patients enrolled in health plans participating in the Vaccine Safety Datalink and diagnosed with GBS from July 2009 through June 2011. Medical records of GBS cases with 2009-10 MIV, 2010-11 trivalent inactivated influenza vaccine (TIV), and/or a medically-attended respiratory or gastrointestinal infection in the 1 through 141 days prior to GBS diagnosis were reviewed and classified according to Brighton Collaboration criteria for diagnostic certainty. Using a case-centered design, logistic regression models adjusted for patient-level time-varying sources of confounding, including seasonal vaccinations and infections in GBS cases and population-level controls. RESULTS: Eighteen confirmed GBS cases received vaccination in the 6 weeks preceding onset, among 1.27 million 2009-10 MIV recipients and 2.80 million 2010-11 TIV recipients. Forty-four confirmed GBS cases had infection in the 6 weeks preceding onset, among 3.77 million patients diagnosed with medically-attended infection. The observed-versus-expected odds that 2009-10 MIV/2010-11 TIV was received in the 6 weeks preceding GBS onset was odds ratio = 1.54, 95% confidence interval (CI), 0.59-3.99; risk difference = 0.93 per million doses, 95% CI, -0.71-5.16. The association between GBS and medically-attended infection was: odds ratio = 7.73, 95% CI, 3.60-16.61; risk difference = 11.62 per million infected patients, 95% CI, 4.49-26.94. These findings were consistent in sensitivity analyses using alternative infection definitions and risk intervals for prior vaccination shorter than 6 weeks. CONCLUSIONS: After adjusting for antecedent infections, we found no evidence for an elevated GBS risk following 2009-10 MIV/2010-11 TIV influenza vaccines. However, the association between GBS and antecedent infection was strongly elevated.

International collaboration to assess the risk of Guillain Barré Syndrome following Influenza A (H1N1) 2009 monovalent vaccines.

BACKGROUND: The global spread of the 2009 novel pandemic influenza A (H1N1) virus led to the accelerated production and distribution of monovalent 2009 Influenza A (H1N1) vaccines (pH1N1). This pandemic provided the opportunity to evaluate the risk of Guillain-Barré syndrome (GBS), which has been an influenza vaccine safety concern since the swine flu pandemic of 1976, using a common protocol among high and middle-income countries. The primary objective of this project was to demonstrate the feasibility and utility of global collaboration in the assessment of vaccine safety, including countries both with and without an established infrastructure for vaccine active safety surveillance. A second objective, included a priori, was to assess the risk of GBS following pH1N1 vaccination. METHODS: The primary analysis used the self-controlled case series (SCCS) design to estimate the relative incidence (RI) of GBS in the 42 days following vaccination with pH1N1 vaccine in a pooled analysis across databases and in analysis using a meta-analytic approach. RESULTS: We found a relative incidence of GBS of 2.42 (95% CI 1.58-3.72) in the 42 days following exposure to pH1N1 vaccine in analysis of pooled data and 2.09 (95% CI 1.28-3.42) using the meta-analytic approach. CONCLUSIONS: This study demonstrates that international collaboration to evaluate serious outcomes using a common protocol is feasible. The significance and consistency of our findings support a conclusion of an association between 2009 H1N1 vaccination and GBS. Given the rarity of the event the relative incidence found does not provide evidence in contradiction to international recommendations for the continued use of influenza vaccines.

Guillain-Barré syndrome incidence in a large United States cohort (2000-2009).

BACKGROUND/AIM: We describe the incidence of Guillain-Barré syndrome (GBS) in a large United States cohort. METHODS: Between 2000 and 2009, we identified visits with an ICD-9 code for GBS (357.0) from all persons with continuous enrollment for at least 1 year. The primary case definition was restricted to emergency department and inpatient visits. We calculated age-standardized rates and used multivariate Poisson regression to assess variation in rates by sex, age, season and year of diagnosis. We tabulated descriptive characteristics and the positive predictive value (PPV) for a subset of the visits with available medical record review. RESULTS: 1,619 visits with the GBS ICD-9 code were identified from 50,290,898 person-years of observation. After considering the PPV (55%) for record-reviewed visits, the age-standardized incidence rate was approximately 1.72/100,000 person-years. The rate was 40% higher for males and increased by 50% for every 10-year increase in age. The rate was 15% higher in winter and spring compared with summer. Rates were higher in more recent years. CONCLUSIONS: GBS rates are higher in males and increase considerably with age. The potential reasons for differences in rates by season and the increased rates in more recent years should be further investigated.

Surveillance for adverse events following receipt of pandemic 2009 H1N1 vaccine in the Post-Licensure Rapid Immunization Safety Monitoring (PRISM) System, 2009-2010.

The Post-Licensure Rapid Immunization Safety Monitoring (PRISM) system is a cohort-based active surveillance network initiated by the US Department of Health and Human Services to supplement preexisting and other vaccine safety monitoring systems in tracking the safety of monovalent pandemic 2009 H1N1 influenza vaccine in the United States during 2009-2010. PRISM investigators conducted retrospective analysis to determine whether 2009 H1N1 vaccination was associated with increased risk of any of 14 prespecified outcomes. Five health insurance and associated companies with 38 million members and 9 state/city immunization registries contributed records on more than 2.6 million doses of 2009 H1N1 vaccine. Data on outcomes came from insurance claims. Complementary designs (self-controlled risk interval, case-centered, and current-vs.-historical comparison) were used to optimize control for confounding and statistical power. The self-controlled risk interval analysis of chart-confirmed Guillain-Barré syndrome found an elevated but not statistically significant incidence rate ratio following receipt of inactivated 2009 H1N1 vaccine (incidence rate ratio = 2.50, 95% confidence interval: 0.42, 15.0) and no cases following live attenuated 2009 H1N1 vaccine. The study did not control for infection prior to Guillain-Barré syndrome, which may have been a confounder. The risks of other health outcomes of interest were generally not significantly elevated after 2009 H1N1 vaccination.

Risk of confirmed Guillain-Barre syndrome following receipt of monovalent inactivated influenza A (H1N1) and seasonal influenza vaccines in the Vaccine Safety Datalink Project, 2009-2010.

An increased risk of Guillain-Barré syndrome (GBS) following administration of the 1976 swine influenza vaccine led to a heightened focus on GBS when monovalent vaccines against a novel influenza A (H1N1) virus of swine origin were introduced in 2009. GBS cases following receipt of monovalent inactivated (MIV) and seasonal trivalent inactivated (TIV) influenza vaccines in the Vaccine Safety Datalink Project in 2009-2010 were identified in electronic data and confirmed by medical record review. Within 1-42 days following vaccination, 9 cases were confirmed in MIV recipients (1.48 million doses), and 8 cases were confirmed in TIV-only recipients who did not also receive MIV during 2009-2010 (1.72 million doses). Five cases following MIV and 1 case following TIV-only had an antecedent respiratory infection, a known GBS risk factor; furthermore, unlike TIV, MIV administration was concurrent with heightened influenza activity. In a self-controlled risk interval analysis comparing GBS onset within 1-42 days following MIV with GBS onset 43-127 days following MIV, the risk difference was 5.0 cases per million doses (95% confidence interval: 0.5, 9.5). No statistically significant increased GBS risk was found within 1-42 days following TIV-only vaccination versus 43-84 days following vaccination (risk difference = 1.1 cases per million doses, 95% confidence interval: -3.1, 5.4). Further evaluation to assess GBS risk following both vaccination and respiratory infection is warranted.

Risk of intussusception following administration of a pentavalent rotavirus vaccine in US infants.

CONTEXT: Current rotavirus vaccines were not associated with intussusception in large prelicensure trials. However, recent postlicensure data from international settings suggest the possibility of a low-level elevated risk, primarily in the first week after the first vaccine dose. OBJECTIVE: To examine the risk of intussusception following pentavalent rotavirus vaccine (RV5) in US infants. DESIGN, SETTING, AND PATIENTS: This cohort study included infants 4 to 34 weeks of age, enrolled in the Vaccine Safety Datalink (VSD) who received RV5 from May 2006-February 2010. We calculated standardized incidence ratios (SIRs), relative risks (RRs), and 95% confidence intervals for the association between intussusception and RV5 by comparing the rates of intussusception in infants who had received RV5 with the rates of intussusception in infants who received other recommended vaccines without concomitant RV5 during the concurrent period and with the expected number of intussusception visits based on background rates assessed prior to US licensure of the RV5 (2001-2005). MAIN OUTCOME MEASURE: Intussusception occurring in the 1- to 7-day and 1- to 30-day risk windows following RV5 vaccination. RESULTS: During the study period, 786,725 total RV5 doses, which included 309,844 first doses, were administered. We did not observe a statistically significant increased risk of intussusception with RV5 for either comparison group following any dose in either the 1- to 7-day or 1- to 30-day risk window. For the 1- to 30-day window following all RV5 doses, we observed 21 cases of intussusception compared with 20.9 expected cases (SIR, 1.01; 95% CI, 0.62-1.54); following dose 1, we observed 7 cases compared with 5.7 expected cases (SIR, 1.23; 95% CI, 0.5-2.54). For the 1- to 7-day window following all RV5 doses, we observed 4 cases compared with 4.3 expected cases (SIR, 0.92; 95% CI, 0.25-2.36); for dose 1, we observed 1 case compared with 0.8 expected case (SIR, 1.21; 95% CI, 0.03-6.75). The upper 95% CI limit of the SIR (6.75) from the historical comparison translates to an upper limit for the attributable risk of 1 intussusception case per 65,287 RV5 dose-1 recipients. CONCLUSION: Among US infants aged 4 to 34 weeks who received RV5, the risk of intussusception was not increased compared with infants who did not receive the rotavirus vaccine.

Suppression of adaptive immune responses during primary SIV infection of sabaeus African green monkeys delays partial containment of viremia but does not induce disease.

One of the most puzzling observations in HIV research is the lack of pathogenicity in most nonhuman primate species that are natural hosts of simian immunodeficiency virus (SIV) infection. Despite this, natural hosts experience a level of viremia similar to humans infected with HIV or macaques infected with SIV. To determine the role of adaptive immune responses in viral containment and lack of disease, we delayed the generation of cellular and humoral immune responses by administering anti-CD8- and anti-CD20 lymphocyte-depleting antibodies to sabaeus African green monkeys (Chlorocebus sabaeus) before challenge with SIV(sab9315BR). In vivo lymphocyte depletion during primary infection resulted in a brief elevation of viremia but not in disease. Based on the magnitude and timing of SIV-specific CD8(+) T-cell responses in the lymphocyte-depleted animals, CD8(+) T-cell responses appear to contribute to viral containment in natural hosts. We found no evidence for a contribution of humoral immune responses in viral containment. These studies indicate that natural hosts have developed mechanisms in addition to classic adaptive immune responses to cope with this lentiviral infection. Thus, adaptive immune responses in natural hosts appear to be less critical for viral containment than in HIV infection.

Inhibition of adaptive immune responses leads to a fatal clinical outcome in SIV-infected pigtailed macaques but not vervet African green monkeys.

African green monkeys (AGM) and other natural hosts for simian immunodeficiency virus (SIV) do not develop an AIDS-like disease following SIV infection. To evaluate differences in the role of SIV-specific adaptive immune responses between natural and nonnatural hosts, we used SIV(agmVer90) to infect vervet AGM and pigtailed macaques (PTM). This infection results in robust viral replication in both vervet AGM and pigtailed macaques (PTM) but only induces AIDS in the latter species. We delayed the development of adaptive immune responses through combined administration of anti-CD8 and anti-CD20 lymphocyte-depleting antibodies during primary infection of PTM (n = 4) and AGM (n = 4), and compared these animals to historical controls infected with the same virus. Lymphocyte depletion resulted in a 1-log increase in primary viremia and a 4-log increase in post-acute viremia in PTM. Three of the four PTM had to be euthanized within 6 weeks of inoculation due to massive CMV reactivation and disease. In contrast, all four lymphocyte-depleted AGM remained healthy. The lymphocyte-depleted AGM showed only a trend toward a prolongation in peak viremia but the groups were indistinguishable during chronic infection. These data show that adaptive immune responses are critical for controlling disease progression in pathogenic SIV infection in PTM. However, the maintenance of a disease-free course of SIV infection in AGM likely depends on a number of mechanisms including non-adaptive immune mechanisms.

Simian immunodeficiency virus (SIV)-specific CD8+ T-cell responses in vervet African green monkeys chronically infected with SIVagm.

African green monkeys (AGM) do not develop overt signs of disease following simian immunodeficiency virus (SIV) infection. While it is still unknown how natural hosts like AGM can cope with this lentivirus infection, a large number of investigations have shown that CD8(+) T-cell responses are critical for the containment of AIDS viruses in humans and Asian nonhuman primates. Here we have compared the phenotypes of T-cell subsets and magnitudes of SIV-specific CD8(+) T-cell responses in vervet AGM chronically infected with SIVagm and rhesus monkeys (RM) infected with SIVmac. In comparison to RM, vervet AGM exhibited weaker signs of immune activation and associated proliferation of CD8(+) T cells as detected by granzyme B, Ki-67, and programmed death 1 staining. By gamma interferon enzyme-linked immunospot assay and intracellular cytokine staining, SIV Gag- and Env-specific immune responses were detectable at variable but lower levels in vervet AGM than in RM. These observations demonstrate that natural hosts like SIV-infected vervet AGM develop SIV-specific T-cell responses, but the disease-free course of infection does not depend on the generation of robust CD8(+) T-cell responses.

Contribution of CD8+ T cells to containment of viral replication and emergence of mutations in Mamu-A*01-restricted epitopes in Simian immunodeficiency virus-infected rhesus monkeys.

Here, we investigated the containment of virus replication in simian immunodeficiency virus (SIV) infection by CD8(+) lymphocytes. Escape mutations in Mamu-A*01 epitopes appeared first in SIV Tat TL8 and then in SIV Gag p11C. The appearance of escape mutations in SIV Gag p11C was coincident with compensatory changes outside of the epitope. Eliminating CD8(+) lymphocytes from rhesus monkeys during primary infection resulted in more rapid disease progression that was associated with preservation of canonical epitopes. These results confirm the importance of cytotoxic T cells in controlling viremia and the constraint on epitope sequences that require compensatory changes to go to fixation.

Increased loss of CCR5+ CD45RA- CD4+ T cells in CD8+ lymphocyte-depleted Simian immunodeficiency virus-infected rhesus monkeys.

Previously we have shown that CD8(+) T cells are critical for containment of simian immunodeficiency virus (SIV) viremia and that rapid and profound depletion of CD4(+) T cells occurs in the intestinal tract of acutely infected macaques. To determine the impact of SIV-specific CD8(+) T-cell responses on the magnitude of the CD4(+) T-cell depletion, we investigated the effect of CD8(+) lymphocyte depletion during primary SIV infection on CD4(+) T-cell subsets and function in peripheral blood, lymph nodes, and intestinal tissues. In peripheral blood, CD8(+) lymphocyte-depletion changed the dynamics of CD4(+) T-cell loss, resulting in a more pronounced loss 2 weeks after infection, followed by a temporal rebound approximately 2 months after infection, when absolute numbers of CD4(+) T cells were restored to baseline levels. These CD4(+) T cells showed a markedly skewed phenotype, however, as there were decreased levels of memory cells in CD8(+) lymphocyte-depleted macaques compared to controls. In intestinal tissues and lymph nodes, we observed a significantly higher loss of CCR5(+) CD45RA(-) CD4(+) T cells in CD8(+) lymphocyte-depleted macaques than in controls, suggesting that these SIV-targeted CD4(+) T cells were eliminated more efficiently in CD8(+) lymphocyte-depleted animals. Also, CD8(+) lymphocyte depletion significantly affected the ability to generate SIV Gag-specific CD4(+) T-cell responses and neutralizing antibodies. These results reemphasize that SIV-specific CD8(+) T-cell responses are absolutely critical to initiate at least partial control of SIV infection.