Clinical Focus


  • Emergency Medicine

Academic Appointments


Professional Education


  • Master's Degree, Stanford University Food Research Institute, International Economics - Agriculture (1995)
  • Residency: Yale School of Medicine Dept of Emergency Medicine (2001) CT
  • Medical Education: Stanford University School of Medicine (1996) CA
  • Board Certification: American Board of Emergency Medicine, Emergency Medicine (2002)

Clinical Trials


  • Evaluation of the 4th Generation QuantiFERON-TB Test (QFT-Plus) for the Detection of Tuberculosis Infection Not Recruiting

    To compare the positivity rate of the investigational assay to the currently approved QuantiFERON-TB Gold In-Tube assay.

    Stanford is currently not accepting patients for this trial. For more information, please contact Mark Holodniy, MD, 650-852-3408.

    View full details

All Publications


  • Promising Strategies to Support COVID-19 Vaccination of Healthcare Personnel: Qualitative Insights from the VHA National Implementation. Journal of general internal medicine Giannitrapani, K. F., Brown-Johnson, C., Connell, N. B., Yano, E. M., Singer, S. J., Giannitrapani, S. N., Thanassi, W., Lorenz, K. A. 2022

    Abstract

    BACKGROUND: In August 2021, up to 30% of Americans were uncertain about taking the COVID-19 vaccine, including some healthcare personnel (HCP).OBJECTIVE: Our objective was to identify barriers and facilitators of the Veterans Health Administration (VHA) HCP vaccination program.DESIGN: We conducted key informant interviews with employee occupational health (EOH) providers, using snowball recruitment.PARTICIPANTS: Participants included 43 VHA EOH providers representing 29 of VHA's regionally diverse healthcare systems.APPROACH: Thematic analysis elucidated 5 key themes and specific strategies recommended by EOH.KEY RESULTS: Implementation themes reflected logistics of distribution (supply), addressinganyvaccine concerns orhesitancy (demand), and learning health system strategies/approaches for shared learnings. Specifically, themes included the following: (1) use interdisciplinary task forces to leverage diverse skillsets for vaccine implementation; (2) invest in processes and align resources with priorities, including creating detailed processes, addressing time trade-offs for personnel involved in vaccine clinics by suspending everything non-essential, designating process/authority to shift personnel where needed, and proactively involving leaders to support resource allocation/alignment; (3) expect and accommodate vaccine buy-in occurring over time: prepare for some HCP's slow buy-in, align buy-in facilitation with identities and motivation, and encourage word-of-mouth and hyper-local testimonials; (4) overcome misinformation with trustworthy communication: tailor communication to individuals and address COVID vaccines "in every encounter," leverage proactive institutional messaging to reinforce information, and invite bi-directional conversations about any vaccine concerns. A final overarching theme focused on learning health system needs and structures: (5) use existing and newly developed communication channels to foster shared learning across teams and sites.CONCLUSIONS: Expecting deliberation allows systems to prepare for complex distribution logistics (supply) and make room for conversations that are trustworthy, bi-directional, and identity aligned (demand). Ideally, organizations provide time for conversations that address individual concerns, foster bi-directional shared decision-making, respect HCP beliefs and identities, and emphasize shared identities as healthcare providers.

    View details for DOI 10.1007/s11606-022-07439-y

    View details for PubMedID 35260957

  • Protecting the healthcare workforce during COVID-19: a qualitative needs assessment of employee occupational health in the US national Veterans Health Administration. BMJ open Brown-Johnson, C., McCaa, M. D., Giannitrapani, S., Singer, S. J., Lorenz, K. A., Yano, E. M., Thanassi, W. T., DeShields, C., Giannitrapani, K. F. 2021; 11 (10): e049134

    Abstract

    OBJECTIVE: Early in the COVID-19 pandemic, US Veterans Health Administration (VHA) employee occupational health (EOH) providers were tasked with assuming a central role in coordinating employee COVID-19 screening and clearance for duty, representing entirely novel EOH responsibilities. In a rapid qualitative needs assessment, we aimed to identify learnings from the field to support the vastly expanding role of EOH providers in a national healthcare system.METHODS: We employed rapid qualitative analysis of key informant interviews in a maximal variation sample on the parameters of job type, rural versus urban and provider gender. We interviewed 21 VHA EOH providers between July and December 2020. This sample represents 15 facilities from diverse regions of the USA (large, medium and small facilities in the Mid-Atlantic; medium sites in the South; large facilities in the West and Pacific Northwest).RESULTS: Five interdependent needs included: (1) infrastructure to support employee population management, including tools that facilitate infection control measures such as contact tracing (eg, employee-facing electronic health records and coordinated databases); (2) mechanisms for information sharing across settings (eg, VHA listserv), especially for changing policy and protocols; (3) sufficiently resourced staffing using detailing to align EOH needs with human resource capital; (4) connected and resourced local and national leaders; and (5) strategies to support healthcare worker mental health.Our identified facilitators for EOH assuming new challenging and dynamically changing roles during COVID-19 included: (A) training or access to expertise; (B) existing mechanisms for information sharing; (C) flexible and responsive staffing; and (D) leveraging other institutional expertise not previously affiliated with EOH (eg, chaplains to support bereavement).CONCLUSIONS: Our needs assessment highlights local and system level barriers and facilitators of EOH assuming expanded roles during COVID-19. Integrating changes both within and across systems and with alignment of human capital will enable EOH preparedness for future challenges.

    View details for DOI 10.1136/bmjopen-2021-049134

    View details for PubMedID 34607860

  • Cumulative Faults with Serial Testing for Latent Tuberculosis in Low-Risk Populations. Annals of the American Thoracic Society Thanassi, W. T., Buchta, W. G. 2016; 13 (7): 1187-1188

    View details for DOI 10.1513/AnnalsATS.201603-213LE

    View details for PubMedID 27388409

  • Negative Tuberculin Skin Test and Prediction of Reversion of QuantiFERON Interferon Gamma Release Assay in US Healthcare Workers INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY Thanassi, W., Noda, A., Hernandez, B., Friedman, L., Dorman, S., Yesavage, J. 2016; 37 (4): 478-482

    Abstract

    QuantiFERON tuberculosis tests (QFT) reverted in (612) 77% of 1,094 low-risk healthcare workers (HCW) testing less than 1.16 IU/mL. Of HCW testing greater than 1.1 IU/mL, 33 (59%) of 56 with negative tuberculin skin tests (TST) reverted vs 8 (6%) of 125 with positive TSTs. Retesting low-risk QFT-positive and TST-negative HCW is prudent.

    View details for DOI 10.1017/ice.2015.324

    View details for Web of Science ID 000372796200018

  • Summary of Meeting Proceedings on Addressing Variability around the Cut Point in Serial Interferon-gamma Release Assay Testing INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY Daley, C. L., Reves, R. R., Beard, M. A., Boyle, J., Clark, R. B., Beebe, J. L., Catanzaro, A., Chen, L., Desmond, E., Dorman, S. E., Hudson, T. W., Lardizabal, A. A., Kapoor, H., Marder, D. C., Miranda, C., Narita, M., Reichman, L., Schwab, D., Seaworth, B. J., Terpeluk, P., Thanassi, W., Kawamura, L. M. 2013; 34 (6): 625-630

    Abstract

    On June 13, 2012, a group of key stakeholders, leaders, and national experts on tuberculosis (TB), occupational health, and laboratory science met in Atlanta, Georgia, to focus national discussion on the higher than expected positive results occurring among low-risk, unexposed healthcare workers undergoing serial testing with interferon-γ release assays (IGRAs). The objectives of the meeting were to present the latest clinical and operational research findings on the topic, to discuss evaluation and treatment algorithms that are emerging in the absence of national guidance, and to develop a consensus on the action steps needed to assist programs and physicians in the interpretation of serial testing IGRA results. This report summarizes its proceedings.

    View details for DOI 10.1086/670635

    View details for Web of Science ID 000318766800013

    View details for PubMedID 23651895

  • Delineating a Retesting Zone Using Receiver Operating Characteristic Analysis on Serial QuantiFERON Tuberculosis Test Results in US Healthcare Workers. Pulmonary medicine Thanassi, W., Noda, A., Hernandez, B., Newell, J., Terpeluk, P., Marder, D., Yesavage, J. A. 2012; 2012: 291294-?

    Abstract

    Objective. To find a statistically significant separation point for the QuantiFERON Gold In-Tube (QFT) interferon gamma release assay that could define an optimal "retesting zone" for use in serially tested low-risk populations who have test "reversions" from initially positive to subsequently negative results. Method. Using receiver operating characteristic analysis (ROC) to analyze retrospective data collected from 3 major hospitals, we searched for predictors of reversion until statistically significant separation points were revealed. A confirmatory regression analysis was performed on an additional sample. Results. In 575 initially positive US healthcare workers (HCWs), 300 (52.2%) had reversions, while 275 (47.8%) had two sequential positive tests. The most statistically significant (Kappa = 0.48, chi-square = 131.0, P < 0.001) separation point identified by the ROC for predicting reversion was the tuberculosis antigen minus-nil (TBag-nil) value at 1.11 International Units per milliliter (IU/mL). The second separation point was found at TBag-nil at 0.72 IU/mL (Kappa = 0.16, chi-square = 8.2, P < 0.01). The model was validated by the regression analysis of 287 HCWs. Conclusion. Reversion likelihood increases as the TBag-nil approaches the manufacturer's cut-point of 0.35 IU/mL. The most statistically significant separation point between those who test repeatedly positive and those who revert is 1.11 IU/mL. Clinicians should retest low-risk individuals with initial QFT results < 1.11 IU/mL.

    View details for DOI 10.1155/2012/291294

    View details for PubMedID 23326660

    View details for PubMedCentralID PMC3544373

  • TENSION PNEUMOPERITONEUM JOURNAL OF EMERGENCY MEDICINE Lin, B. W., Thanassi, W. 2010; 38 (1): 57-59
  • FEVER, ABDOMINAL PAIN, AND LEUKOPENIA IN A 13-YEAR-OLD: A CASE-BASED REVIEW OF MENINGOCOCCEMIA JOURNAL OF EMERGENCY MEDICINE Hsia, R. Y., Wang, E., Thanassi, W. T. 2009; 37 (1): 21-28

    Abstract

    The presenting symptoms of meningococcemia are protean, and the illness is rapidly progressive and often fatal, making it simultaneously one of the most dangerous and most important illnesses the Emergency Physician can encounter. It attacks the young and it is highly contagious. This report uses one of the many unusual presentations of meningococcemia as a framework for discussing the epidemiology, presentation, diagnosis, and treatment of meningococcal disease.

    View details for DOI 10.1016/j.jemermed.2007.11.083

    View details for Web of Science ID 000267505800005

    View details for PubMedID 18657927

  • Impact of HIV on admissions and deaths in a tuberculosis hospital - recommendations for admission and discharge criteria SAMJ SOUTH AFRICAN MEDICAL JOURNAL Thanassi, W., Post, F. A., Shean, K., Bekker, L. G., Maartens, G. 2003; 93 (6): 463-464

    Abstract

    Mortality and HIV prevalence rose concordantly at Brooklyn Chest Hospital from 1998 to 2001. Death and unconfirmed tuberculosis (TB) (15% of adult admissions in a sample from 2000) were associated with HIV seropositivity. Excluding unconfirmed TB and shortening length of stay would increase the number of patients able to benefit from hospitalisation.

    View details for Web of Science ID 000184273800032

    View details for PubMedID 12916389

  • The Lyme disease vaccine: Conception, development, and implementation ANNALS OF INTERNAL MEDICINE Thanassi, W. T., Schoen, R. T. 2000; 132 (8): 661-668

    Abstract

    In the past 20 years, remarkable strides have been made toward understanding and preventing Lyme disease in humans. In December 1998, the U.S. Food and Drug Administration approved a recombinant outer surface protein A vaccine against Lyme disease (LYMErix, SmithKline Beecham, Philadelphia, Pennsylvania). The vaccine, which is derived from a lipidated outer surface protein of the causative spirochete Borrelia burgdorferi, is important because it may decrease the morbidity and financial costs associated with Lyme disease. Its mechanism is unique because it works inside the tick vector itself, preventing the human from becoming infected.

    View details for DOI 10.7326/0003-4819-132-8-200004180-00009

    View details for Web of Science ID 000086497500008

    View details for PubMedID 10766685

  • Successful vaccination for Lyme disease: a novel mechanism. Expert opinion on investigational drugs Thanassi, W. T., Schoen, R. T. 1999; 8 (1): 29-35

    Abstract

    Two vaccines are on the horizon for the prevention of Lyme disease, the most common vector-borne illness in the US and Europe. This review describes the pathogenesis and clinical illness of Lyme disease, as well as the sequence of events that led to the development of these novel vaccines. The results of the most recent Phase III human trials are reported.

    View details for DOI 10.1517/13543784.8.1.29

    View details for PubMedID 15992056

  • Immunizations for international travelers WESTERN JOURNAL OF MEDICINE Thanassi, W. T. 1998; 168 (3): 197-202

    Abstract

    Each year more than 45 million Americans travel abroad for work or pleasure, and over 20 million of these travel to rural areas or developing countries. While the major medical risks of international travel are often exaggerated, the incidence of minor illness is not. Persons going to Asia, Africa, or Latin America for one month run a 65% to 75% chance of becoming ill, although only 1% will require hospitalization. The two most common illnesses that affect travelers, which do have immunizations and are often overlooked by physicians, are influenza and hepatitis A. The risk of illness to the traveler varies by health and age status, by the region to be visited, by the time of year, and by the length of the journey. Immunization advice for the traveler, therefore, is complicated and is best approached in a systematic manner. This article outlines six steps to sound immunization advice. These steps include ascertaining the traveler's special individual needs, routine immunization status, and routine travel immunization status, as well as the entry requirements for the country to be visited, geographically indicated vaccines, and immunizations as indicated for extended stays abroad.

    View details for Web of Science ID 000072574000015

    View details for PubMedID 9549428

    View details for PubMedCentralID PMC1304870

  • Immunizations and travel. Emergency medicine clinics of North America Thanassi, W. T., Weiss, E. L. 1997; 15 (1): 43-70

    Abstract

    Determining the appropriate immunizations for international travelers is a complex, multifaceted process. This article proposes a stepwise and systematic approach to the immunization needs of the traveler-patient. Vaccines for routine health maintenance as well as special issues of the elderly, pregnant, immunocompromised, and child are important in the initial evaluation. Specific travel immunizations (i.e., those for routine travel, those required by a country, those that are geographically indicated and immunizations for extended stays) comprise the remainder of the immunization interview. Health care providers should also be familiar with cost and risk statistics, both the risk of the traveler contracting an illness overseas and the risk of side effects from the vaccines themselves. With such cost-benefit analysis, the provider can offer the traveler immunizations as well as information.

    View details for DOI 10.1016/S0733-8627(05)70285-6

    View details for PubMedID 9056570

  • Acceptability of a rice-based oral rehydration solution in Port Moresby General Hospital's Children's Outpatient Department. Papua and New Guinea medical journal Todaro, W., Wall, C., Edwards, K., Cleghorn, G. 1995; 38 (4): 278-83

    Abstract

    The guardians of children brought to the Port Moresby General Hospital's Children's Outpatient Department with a chief complaint of diarrhoeal disease were questioned regarding their preference of glucose-based vs rice-based oral rehydration solution (ORS) in order to determine the acceptability of a rice-based ORS. Of the 93 guardians interviewed, greater than 60% preferred the glucose-based solution in its mixability, appearance and taste, and 65% initially reported that their children preferred the taste of the glucose solution. However, after a 30-minute trial, only 58% of children still preferred the glucose solution. In a country where diarrhoeal disease is a leading cause of child death and guardians are the primary health care providers, the acceptability of an ORS is critical to the morbidity and mortality of Papua New Guinea's children.

    View details for PubMedID 9522868

  • A 3-hour quantitative comparison of glucose-based versus rice-based oral rehydration solution intake by children with diarrhoea in Port Moresby General Hospital. Papua and New Guinea medical journal Wall, C., Todaro, W., Edwards, K., Cleghorn, G. 1995; 38 (4): 284-6

    Abstract

    Measurements were made of the intake of a WHO/UNICEF glucose-based and a rice cereal-based oral rehydration solution (ORS) by children with diarrhoea. Twenty children who presented to the Children's Outpatient Department at Port Moresby General Hospital with acute diarrhoea and mild dehydration were randomly assigned to an ORS and measurements were taken over the following 3 hours. For data analysis, the patients were paired by weight. Testing the means of the paired samples by t test showed that there was no significant difference between the amount of rice ORS and the amount of glucose ORS taken over 3 hours.

    View details for PubMedID 9522869