Clinical Focus


  • Fellow
  • Infectious Diseases
  • Planetary Health
  • Emerging pathogens
  • Diagnostic challenges
  • Underserved patients
  • Women's health
  • Recurrent UTIs
  • Critical Care

Honors & Awards


  • Making your Mark Award, University of Southern California, School of Policy, Planning, and Development (2010)
  • Julian Wolfsohn Award for Outstanding Performance in Internal Medicine, Stanford University (2020)

Professional Education


  • Fellowship, Stanford University, Critical Care Medicine
  • Fellowship, Stanford University, Infectious Diseases and Geographic Medicine (2023)
  • Residency, Stanford University, Global Health/Internal Medicine (2021)
  • MD, University of California, San Francisco, School of Medicine (2018)
  • BS, University of Southern California, School of Policy, Planning, and Development (2010)

All Publications


  • Treatment of Mpox with Suspected Tecovirimat Resistance in Immunocompromised Patient, United States, 2022 EMERGING INFECTIOUS DISEASES Contag, C. A., Mische, L., Fong, I., Karan, A., Vaidya, A., Mccormick, D. W., Bower, W., Hacker, J. K., Johnson, K., Sanjuan, P., Crebbin, L., Temmins, C., Sahni, H., Bogler, Y., Cooper, J. D., Narasimhan, S. 2023; 29 (12): 2520-2523

    Abstract

    Reports of tecovirimat-resistant mpox have emerged after widespread use of antiviral therapy during the 2022 mpox outbreak. Optimal management of patients with persistent infection with or without suspected resistance is yet to be established. We report a successfully treated case of severe mpox in California, USA, that had suspected tecovirimat resistance.

    View details for DOI 10.3201/eid2912.230849

    View details for Web of Science ID 001113404100022

    View details for PubMedID 37856215

    View details for PubMedCentralID PMC10683816

  • Low infectivity among asymptomatic patients with a positive severe acute respiratory coronavirus virus 2 (SARS-CoV-2) admission test at a tertiary care center, 2020-2022. Infection control and hospital epidemiology Tayyar, R., Kiener, M. A., Liang, J. W., Contreras, G., Rodriguez-Nava, G., Zimmet, A. N., Contag, C. A., Srinivasan, K., McIntyre, K., Subramanian, A., Shepard, J., Tompkins, L. S., Pinsky, B. A., Salinas, J. L. 2023: 1-3

    Abstract

    We used a strand-specific RT-qPCR to evaluate viral replication as a surrogate for infectiousness among 242 asymptomatic inpatients with a positive severe acute respiratory coronavirus virus 2 (SARS-CoV-2) admission test. Only 21 patients (9%) had detectable SARS-CoV-2 minus-strand RNA. Because most patients were found to be noninfectious, our findings support the suspension of asymptomatic admission testing.

    View details for DOI 10.1017/ice.2023.210

    View details for PubMedID 37746805

  • Two cases of MPXV infection during pregnancy in heterosexual cisgender women without classic cutaneous lesions, Northern California, 2022. IDCases Renfro, Z. T., Contag, C. A., Lu, J., Solis, D., Huang, C., Sahoo, M. K., Yamamoto, F., Mah, J., Jones, M. S., Lin, J., Levy, V., Pinsky, B. A. 2023; 33: e01881

    Abstract

    As part of an epidemiologic survey, we screened remnant samples collected for STI testing for mpox virus. We identified two cases of presumed MPXV infection in pregnant, heterosexual cisgender women. Here, we describe their pregnancy and birth outcomes. Both patients required induction of labor and experienced labor complicated by chorioamnionitis.

    View details for DOI 10.1016/j.idcr.2023.e01881

    View details for PubMedID 37680215

    View details for PubMedCentralID PMC10480306

  • Monitoring routes of transmission for human mpox LANCET Karan, A., Contag, C. A., Pinksy, B. 2023; 402 (10402): 608-609
  • Use of a severe acute respiratory coronavirus virus 2 (SARS-CoV-2) strand-specific assay to evaluate for prolonged viral replication >20 days from illness onset. Infection control and hospital epidemiology Ferguson, J. D., Tayyar, R., Contreras, G., Kiener, M., Zimmet, A. N., Contag, C. A., Rodriguez Nava, G., Tompkins, L. S., Shepard, J., Rosenthal, A., Subramanian, A. K., Pinsky, B. A., Salinas, J. L. 2023: 1-3

    Abstract

    Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) real-time reverse-transcription polymerase chain reaction (rRT-PCR) strand-specific assay can be used to identify active SARS-CoV-2 viral replication. We describe the characteristics of 337 hospitalized patients with at least 1 minus-strand SARS-CoV-2 assay performed >20 days after illness onset. This test is a novel tool to identify high-risk hospitalized patients with prolonged SARS-CoV-2 replication.

    View details for DOI 10.1017/ice.2023.105

    View details for PubMedID 37381726

  • Health inequities continue to drive the public health threat of mpox. BMJ (Clinical research ed.) Karan, A., Contag, C., Barry, M. 2023; 381: p1391

    View details for DOI 10.1136/bmj.p1391

    View details for PubMedID 37353231

  • Prevalence of Mpox (Monkeypox) in patients undergoing STI screening in northern California, April-September 2022. Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology Contag, C. A., Renfro, Z. T., Lu, J., Shen, S., Karan, A., Solis, D., Huang, C., Sahoo, M. K., Yamamoto, F., Jones, M. S., Lin, J., Levy, V., Pinsky, B. A. 2023; 164: 105493

    Abstract

    Despite the sharp increase in mpox (formerly monkeypox) incidence and the wide geographic spread of mpox during the 2022 outbreak, the community prevalence of infection remains poorly characterized. This study is a retrospective epidemiologic survey to estimate mpox prevalence.Samples obtained for sexually transmitted infection (STI) testing from April to September 2022 in the public hospital and clinic system of San Mateo County, California were screened for mpox virus (MPXV) using polymerase chain reaction.16/1,848 samples from 11/1,645 individuals were positive for MPXV by qPCR. 4/11 individuals with positive MPXV testing were cisgender women, 2 of whom were pregnant at the time of sample collection. Both deliveries were complicated by chorioamnionitis. Anorectal and oropharyngeal samples were the most likely to be positive for MPXV (4/60 anorectal samples and 4/66 oropharyngeal samples compared with 5/1,264 urine samples and 3/445 vaginal samples).Our study is one of the first epidemiologic surveys for MPXV infection outside of sexual health/STI clinic settings. Relatively high rates of MPXV from oropharyngeal and anorectal samples reinforces the importance of MPXV testing at various anatomic sites, particularly if patients are presenting with non-lesional symptoms (pharyngitis, proctitis). However, the United States Food and Drug Administration (FDA) has not yet authorized non-lesional MPXV testing. The identification of MPXV in women in our cohort suggests that the rates of mpox in women may have previously been underestimated and highlights the risk of pregnancy complications associated with mpox.

    View details for DOI 10.1016/j.jcv.2023.105493

    View details for PubMedID 37220710

    View details for PubMedCentralID PMC10184869

  • Retrospective Screening of Clinical Samples for Monkeypox Virus DNA, California, USA, 2022. Emerging infectious diseases Contag, C. A., Lu, J., Renfro, Z. T., Karan, A., Salinas, J. L., Khan, M., Solis, D., Sahoo, M. K., Yamamoto, F., Pinsky, B. A. 2023; 29 (4): 848-850

    Abstract

    We retrospectively screened oropharyngeal and rectal swab samples originally collected in California, USA, for Chlamydia trachomatis and Neisseria gonorrhoeae testing for the presence of monkeypox virus DNA. Among 206 patients screened, 17 (8%) had samples with detectable viral DNA. Monkeypox virus testing from mucosal sites should be considered for at-risk patients.

    View details for DOI 10.3201/eid2904.221576

    View details for PubMedID 36918374

    View details for PubMedCentralID PMC10045697

  • Erythema Gyratum Repens Secondary to Pulmonary Tuberculosis. Annals of internal medicine Contag, C. A., Maloney, N., Tayyar, R., Aleshin, M. A., Novoa, R. A., Ho, D. Y. 2023

    View details for DOI 10.7326/L22-0453

    View details for PubMedID 36913686

  • Case Report: Monkeypox - Not Just a Rash. The American journal of tropical medicine and hygiene Contag, C. A., Karan, A., Studemeister, L., Bansil, R., Fong, I., Srinivasan, K., Salinas, J. L., Narasimhan, S., Cooper, J. D., Sahni, H. 2023

    Abstract

    Mpox (formally monkeypox) is an Orthopoxvirus associated with both zoonotic and person-to-person spread. Human mpox classically presents with rash and systemic symptoms. Although sporadic outbreaks of mpox have occurred worldwide, the 2022 outbreak is the first of pandemic significance. Thousands of geographically dispersed cases were reported beginning in May 2022. The clinical presentations and outcomes of mpox infection have varied greatly based on viral clade. Further guidance is needed for clinicians to diagnose and treat this emerging infection. We present five clinical vignettes of confirmed cases diagnosed in June and July 2022 in northern California to demonstrate the range of mpox disease, including myocarditis, pharyngitis, epididymitis, and proctitis. We note a significant overlap with HIV infection and a high rate of concurrent sexually transmitted infection. Given the heterogenous presentations of mpox disease, clinicians should maintain a high degree of suspicion in patients with oropharyngeal or genital lesions, proctitis, or new rash.

    View details for DOI 10.4269/ajtmh.22-0626

    View details for PubMedID 36716741

  • Use of a SARS-CoV-2 Strand-specific Assay to detect Relapse or Ongoing Infection at a Tertiary Care Center, California 2020–2022 Open Forum Infectious Diseases Contreras Anez, G. A., Ferguson, J., Contag, C. A., Tompkins, L. S., Shepard, J., Rosenthal, A., Subramanian, A., Pinsky, B. A., Salinas, J. 2022; 9 (Supplement 2)

    View details for DOI 10.1093/ofid/ofac492.089

  • Critical care service delivery across healthcare systems in low-income and low-middle-income countries: protocol for a systematic review. BMJ open Lim, A. G., Kivlehan, S., Losonczy, L. I., Murthy, S., Dippenaar, E., Lowsby, R., Yang, M. L., Jaung, M. S., Stephens, P. A., Benzoni, N., Sefa, N., Bartlett, E. S., Chaffay, B. A., Haridasa, N., Velasco, B. P., Yi, S., Contag, C. A., Rashed, A. L., McCarville, P., Sonenthal, P. D., Shukur, N., Bellou, A., Mickman, C., Ghatak-Roy, A., Ferreira, A., Adhikari, N. K., Reynolds, T. 2021; 11 (8): e048423

    Abstract

    INTRODUCTION: Critical care in low-income and low-middle income countries (LLMICs) is an underdeveloped component of the healthcare system. Given the increasing growth in demand for critical care services in LLMICs, understanding the current capacity to provide critical care is imperative to inform policy on service expansion. Thus, our aim is to describe the provision of critical care in LLMICs with respect to patients, providers, location of care and services and interventions delivered.METHODS AND ANALYSIS: We will search PubMed/MEDLINE, Web of Science and EMBASE for full-text original research articles available in English describing critical care services that specify the location of service delivery and describe patients and interventions. We will restrict our review to populations from LLMICs (using 2016 World Bank classifications) and published from 1 January 2008 to 1 January 2020. Two-reviewer agreement will be required for both title/abstract and full text review stages, and rate of agreement will be calculated for each stage. We will extract data regarding the location of critical care service delivery, the training of the healthcare professionals providing services, and the illnesses treated according to classification by the WHO Universal Health Coverage Compendium.ETHICS AND DISSEMINATION: Reviewed and exempted by the Stanford University Office for Human Subjects Research and IRB on 20 May 2020. The results of this review will be disseminated through scholarly publication and presentation at regional and international conferences. This review is designed to inform broader WHO, International Federation for Emergency Medicine and partner efforts to strengthen critical care globally.PROSPERO REGISTRATION NUMBER: CRD42019146802.

    View details for DOI 10.1136/bmjopen-2020-048423

    View details for PubMedID 34462281

  • Spontaneous loss of surface antigen among adults living with chronic hepatitis B virus infection: a systematic review and pooled meta-analyses LANCET GASTROENTEROLOGY & HEPATOLOGY Zhou, K., Contag, C., Whitaker, E., Terrault, N. 2019; 4 (3): 227–38

    Abstract

    Spontaneous loss of HBsAg (known as functional cure) in patients with chronic hepatitis B virus (HBV) infection significantly reduces liver-related complications. HBsAg loss has been suggested to be higher in non-endemic regions than in endemic regions in individual studies. We systematically determined a pooled annual rate of HBsAg loss in adults with untreated chronic HBV infection and examined the effect of regional endemicity.In this systematic review and meta-analysis, we searched PubMed and Embase for observational cohort studies and non-treatment arms of randomised controlled trials reporting proportions of patients with chronic HBV infection that achieved spontaneous HBsAg loss, published up to Oct 1, 2018. We excluded randomised controlled trials from meta-analyses because of substantial cohort differences. Two reviewers (KZ and CC) independently extracted data from accepted full-text studies, with discrepancies discussed with a third reviewer (NT). We assessed rate of HBsAg loss, and stratified results by whether the underlying cohort arose primarily from an endemic region (defined as having prevalence of chronic HBV greater than 2%) or non-endemic region. This study is registered with PROSPERO, number CRD42018074086.Of 5186 studies screened, 67 (11 randomised controlled trials, 39 prospective and 17 retrospective cohort studies) met the inclusion criteria and 56 were included in meta-analyses after exclusion of randomised controlled trials. Spontaneous HBsAg loss occurred in 3837 (7·8%) of 48 972 patients, with cumulative 352 381 person-years of follow-up. The pooled annual incidence of HBsAg loss was 1·17% (95% CI 0·94-1·41, I2=97%). Rates did not differ by endemicity: 1·19% (0·88-1·54) in endemic versus 1·29% (0·99-1·62) in non-endemic cohorts.Globally, spontaneous HBsAg loss occurs infrequently (about 1% per year) in treatment-naive adults with chronic HBV infection. The low and homogeneous rate of HBsAg loss highlights the need for new therapeutics aimed at achieving functional cure across different patient groups and geographical regions.NIH National Institute of Diabetes and Digestive and Kidney Diseases.

    View details for PubMedID 30679109

  • Whole-Genome mRNA Gene Expression Differs Between Patients With and Without Delirium. Journal of geriatric psychiatry and neurology Kalantar, K., LaHue, S. C., DeRisi, J. L., Sample, H. A., Contag, C. A., Josephson, S. A., Wilson, M. R., Douglas, V. C. 2018; 31 (4): 203-210

    Abstract

    To identify differences in gene expression between patients with in-hospital delirium from a known etiology (urinary tract infection [UTI]) and patients with delirium from an unknown etiology, as well as from nondelirious patients.Thirty patients with delirium (8 with UTI) and 21 nondelirious patients (11 with UTI) were included in this prospective case-control study. Transcriptomic profiles from messenger RNA sequencing of peripheral blood were analyzed for gene expression and disease-specific pathway enrichment patterns, correcting for systemic inflammatory response syndrome. Genes and pathways with significant differential activity based on Fisher exact test ( P < .05, |Z score| >2) are reported.Patients with delirium with UTI, compared to patients with delirium without UTI, exhibited significant activation of interferon signaling, upstream cytokines, and transcription regulators, as well as significant inhibition of actin cytoskeleton, integrin, paxillin, glioma invasiveness signaling, and upstream growth factors. All patients with delirium, compared to nondelirious patients, had significant complement system activation. Among patients with delirium without UTI, compared to nondelirious patients without UTI, there was significant activation of elF4 and p7056 K signaling.Differences exist in gene expression between delirious patients due to UTI presence, as well as due to the presence of delirium alone. Transcriptional profiling may help develop etiology-specific biomarkers for patients with delirium.

    View details for DOI 10.1177/0891988718785774

    View details for PubMedID 29991314

    View details for PubMedCentralID PMC6817976