Publications by authors named "Chad D Nix"

The yellow fever vaccine 17D has controlled yellow fever for almost 90 years and is considered highly successful. However, with recent outbreaks in South America and Africa, yellow fever continues to represent a significant threat to public and global health. Despite its longstanding success, few studies have characterized the capacity of 17D-immune sera to neutralize wild-type (WT) yellow fever viruses (YFVs).

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Background: Health care-associated infections (HAIs) pose a significant concern for patient safety, impacting one in 31 hospitalized patients in the United States. Traditional infection prevention strategies emphasize clinical and procedural factors. However, emerging evidence highlights the critical role of social determinants of health (SDOH).

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Although a live-attenuated yellow fever (YF) vaccine is known to elicit durable immunity, antibody titers may wane after vaccination. This study evaluated long-term immunity after vaccination against YF among individuals who resided in Korea and were vaccinated with YF virus- 17D prior to international travel. Serum was collected between December 2018 and December 2019 at the National Medical Center, Republic of Korea, from YF vaccine recipients who had been vaccinated for more than five years prior to sample collection.

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Infections with Chikungunya virus, a mosquito-borne alphavirus, cause an acute febrile syndrome often followed by chronic arthritis that persists for months to years post-infection. Neutralizing antibodies are the primary immune correlate of protection elicited by infection, and the major goal of vaccinations in development. Using convalescent blood samples collected from both endemic and non-endemic human subjects at multiple timepoints following suspected or confirmed chikungunya infection, we identified antibodies with broad neutralizing properties against other alphaviruses within the Semliki Forest complex.

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Objectives: To assess HIV pre-exposure prophylaxis (PrEP) prescribing habits by primary care providers and the number of patients at risk of HIV acquisition at a single medical centre in the Northwestern USA from 1 July 2018 to 31 June 2020.

Methods: An electronic cross-sectional survey was administered in April and May 2021 to providers in family medicine, internal medicine, adolescent and young adult health, student health and women's health clinics affiliated with the medical centre with questions pertaining to PrEP prescribing practices. Electronic medical record abstraction was used to quantify the number of eligible patients who sought care in primary care departments and the adherence to PrEP initiation guidelines from 1 July 2018 to 31 June 2020.

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In June 2021, a task force commissioned by the Board of Directors of the Association for Professionals in Infection Prevention and Epidemiology (APIC) evaluated the landscape of health inequity and health disparities as they apply to infection prevention in health care settings. This task force, consisting of infection preventionists across the country, convened to evaluate current literature, identify relevant issues and make recommendations to the APIC Board of Directors for action steps to be taken.

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We aimed to determine absolute and relative risks of either symptomatic or asymptomatic SARS-CoV-2 infection for late cardiovascular (CV) events and all-cause mortality. We conducted a retrospective double cohort study of patients with either symptomatic or asymptomatic SARS-CoV-2 infection (COVID-19+ cohort) and its documented absence (COVID-19- cohort). The study investigators drew a simple random sample of records from all patients under the Oregon Health & Science University Healthcare (n = 65,585), with available COVID-19 test results, performed March 1, 2020 to September 13, 2020.

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Yellow fever vaccine-associated neurotropic disease (YEL-AND) is a rare and serious complication following vaccination with the 17D live attenuated yellow fever vaccine. Cases of YEL-AND have presented as acute inflammatory demyelinating polyneuropathy, acute disseminated encephalomyelitis, and meningoencephalitis. To date, intracranial imaging of the progression and resolution of this disease has been minimally depicted in the literature.

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Under-recognition of dengue infection may lead to increased morbidity and mortality, whereas early detection is shown to help improve patient outcomes. Recent incidence and outbreak reports of dengue virus in the United States and other temperate regions where dengue was not typically seen have raised concerns regarding appropriate diagnosis and management by healthcare providers unfamiliar with the disease. This study aimed to describe self-reported clinical symptoms of dengue fever in a non-endemic cohort and to establish a clinically useful predictive algorithm based on presenting features that can assist in the early evaluation of potential dengue infection.

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Clostridioides difficile infection rates are higher in hospitalized hematopoietic stem cell transplantation (HSCT) recipients and patients with hematologic malignancy (HM) compared with the general population. This is related both to extensive exposure to antibiotics as well as to frequent and often prolonged hospitalization. In this population, with numerous potential causes of diarrhea, a subset of C difficile detected is presumed to represent colonization rather than clinical infection.

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Zika virus (ZIKV) emerged as a global public health threat throughout the Americas since 2014. Phylogenetically, the virus is composed of three main lineages, an African, Asian, and American lineage. The recent emergence and spread of ZIKV has raised questions regarding the breadth and potency of human primary ZIKV immune sera against antigenically diverse ZIKV.

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Background: The once-in-a-lifetime recommendation for vaccination against yellow fever virus (YFV) has been controversial, leading to increased scrutiny of the durability of immunity after 17D vaccination.

Methods: This is a cross-sectional analysis of 17D vaccinees living in nonendemic Portland, Oregon. Neutralization assays were used to determine YFV immunity.

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Chikungunya virus (CHIKV) and Zika virus (ZIKV) have recently emerged as globally important infections. This study aimed to explore the spatiotemporal heterogeneity in the occurrence of CHIKV and ZIKV outbreaks throughout the major international seaport city of Barranquilla, Colombia in 2014 and 2016 and the potential for clustering. Incidence data were fitted using multiple Bayesian Poisson models based on multiple explanatory variables as potential risk factors identified from other studies and options for random effects.

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