Efficacy and safety of azithromycin versus placebo to treat lower respiratory tract infections associated with low procalcitonin: a randomised, placebo-controlled, double-blind, non-inferiority trial.
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2023-04
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Abstract
Background
Lower respiratory tract infections are frequently treated with antibiotics, despite a viral cause in many cases. It remains unknown whether low procalcitonin concentrations can identify patients with lower respiratory tract infection who are unlikely to benefit from antibiotics. We aimed to compare the efficacy and safety of azithromycin versus placebo to treat lower respiratory tract infections in patients with low procalcitonin.Methods
We conducted a randomised, placebo-controlled, double-blind, non-inferiority trial at five health centres in the USA. Adults aged 18 years or older with clinically suspected non-pneumonia lower respiratory tract infection and symptom duration from 24 h to 28 days were eligible for enrolment. Participants with a procalcitonin concentration of 0·25 ng/mL or less were randomly assigned (1:1), in blocks of four with stratification by site, to receive over-encapsulated oral azithromycin 250 mg or matching placebo (two capsules on day 1 followed by one capsule daily for 4 days). Participants, non-study clinical providers, investigators, and study coordinators were masked to treatment allocation. The primary outcome was efficacy of azithromycin versus placebo in terms of clinical improvement at day 5 in the intention-to-treat population. The non-inferiority margin was -12·5%. Solicited adverse events (abdominal pain, vomiting, diarrhoea, allergic reaction, or yeast infections) were recorded as a secondary outcome. This trial is registered with ClinicalTrials.gov, NCT03341273.Findings
Between Dec 8, 2017, and March 9, 2020, 691 patients were assessed for eligibility and 499 were enrolled and randomly assigned to receive azithromycin (n=249) or placebo (n=250). Clinical improvement at day 5 was observed in 148 (63%, 95% CI 54 to 71) of 238 participants with full data in the placebo group and 155 (69%, 61 to 77) of 227 participants with full data in the azithromycin group in the intention-to-treat analysis (between-group difference -6%, 95% CI -15 to 2). The 95% CI for the difference did not meet the non-inferiority margin. Solicited adverse events and the severity of solicited adverse events were not significantly different between groups at day 5, except for increased abdominal pain associated with azithromycin (47 [23%, 95% CI 18 to 29] of 204 participants) compared with placebo (35 [16%, 12 to 21] of 221; between-group difference -7% [95% CI -15 to 0]; p=0·066).Interpretation
Placebo was not non-inferior to azithromycin in terms of clinical improvement at day 5 in adults with lower respiratory tract infection and a low procalcitonin concentration. After accounting for both the rates of clinical improvement and solicited adverse events at day 5, it is unclear whether antibiotics are indicated for patients with lower respiratory tract infection and a low procalcitonin concentration.Funding
National Institute of Allergy and Infectious Diseases, bioMérieux.Type
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Tsalik, Ephraim L, Nadine G Rouphael, Ruxana T Sadikot, Maria C Rodriguez-Barradas, Micah T McClain, Dana M Wilkins, Christopher W Woods, Geeta K Swamy, et al. (2023). Efficacy and safety of azithromycin versus placebo to treat lower respiratory tract infections associated with low procalcitonin: a randomised, placebo-controlled, double-blind, non-inferiority trial. The Lancet. Infectious diseases, 23(4). pp. 484–495. 10.1016/s1473-3099(22)00735-6 Retrieved from https://hdl.handle.net/10161/26952.
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Scholars@Duke

Ephraim Tsalik
My research at Duke has focused on understanding the dynamic between host and pathogen so as to discover and develop host-response markers that can diagnose and predict health and disease. This new and evolving approach to diagnosing illness has the potential to significantly impact individual as well as public health considering the rise of antibiotic resistance.
With any potential infectious disease diagnosis, it is difficult, if not impossible, to determine at the time of presentation what the underlying cause of illness is. For example, acute respiratory illness is among the most frequent reasons for patients to seek care. These symptoms, such as cough, sore throat, and fever may be due to a bacterial infection, viral infection, both, or a non-infectious condition such as asthma or allergies. Given the difficulties in making the diagnosis, most patients are inappropriately given antibacterials. However, each of these etiologies (bacteria, virus, or something else entirely) leaves a fingerprint embedded in the host’s response. We are very interested in finding those fingerprints and exploiting them to generate new approaches to understand, diagnose, and manage disease.
These principles also apply to sepsis, defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Just as with acute respiratory illness, it is often difficult to identify whether infection is responsible for a patient’s critical illness. We have embarked on a number of research programs that aim to better identify sepsis; define sepsis subtypes that can be used to guide future clinical research; and to better predict sepsis outcomes. These efforts have focused on many systems biology modalities including transcriptomics, miRNA, metabolomics, and proteomics. Consequently, our Data Science team has utilized these highly complex data to develop new statistical methods, furthering both the clinical and statistical research communities.
These examples are just a small sampling of the breadth of research Dr. Tsalik and his colleagues have conducted.
In April 2022, Dr. Tsalik has joined Danaher Diagnostics as the VP and Chief Scientific Officer for Infectious Disease, where he is applying this experience in biomarkers and diagnostics to shape the future of diagnostics in ID.

Micah Thomas McClain

Christopher Wildrick Woods
1. Emerging Infections
2. Global Health
3. Epidemiology of infectious diseases
4. Clinical microbiology and diagnostics
5. Bioterrorism Preparedness
6. Surveillance for communicable diseases
7. Antimicrobial resistance

Geeta Krishna Swamy
Dr. Geeta Swamy, MD, is Professor of Obstetrics and Gynecology in the Division of Maternal-Fetal Medicine, having served as the director of the Duke Perinatal Research Center and Vice Chair for Research and Faculty Development in the Department of ObGyn. She has achieved international acclaim as a clinician researcher and expert in the field of maternal immunization and perinatal infection. As a consultant to the World Health Organization, Dr. Swamy contributes her knowledge to advance international work to evaluate the immunogenicity, safety, and efficacy of vaccines in pregnant women. The American College of ObGyn has grown to be the “collective voice” for women’s health, and Dr. Swamy has been a leader within that organization for the last two decades. She currently serves as the Co-Principal Investigator for the NIH-NIAID Vaccine Treatment and Evaluation (VTEU) and CDC Clinical Immunization Safety Assessment. In addition, she has been a leader at Duke and nationally in promoting a culture of scientific integrity and transparency in research. She has been instrumental in developing and leading the School of Medicine’s research initiatives in administration, regulatory oversight, and compliance. In 2018, she became Vice Dean for Scientific Integrity in the School of Medicine and Associate Vice President for Research for Duke University. In these roles she oversees the Duke Office of Scientific Integrity (DOSI) which houses the Advancing Scientific Integrity, Services, & Training (ASIST) initiative, conflict of interest, clinical quality management, incident response in research, and research misconduct. She also oversees the Duke Office of Research Initiatives, the Duke Health IRB, Office of Research Administration (ORA), and Office of Research Contracts (ORC).

Emmanuel Benjamin Walter
Dr. Emmanuel Walter, MD, MPH, Professor of Pediatrics, serves as the Duke Human Vaccine Institute (DHVI) Chief Medical Officer and directs the Duke Vaccine and Trials Unit. In these roles, Dr. Walter provides strategic and operational leadership for clinical research conducted at the Institute. In addition, he provides oversight of regulatory compliance for DHVI clinical research activities.
Dr. Walter has dedicated his career to advancing research and clinical practice in vaccinology, infectious diseases, and child health. He currently serves as the principal investigator for the Duke Clinical Core of the Collaborative Influenza Vaccine Innovations Centers (CIVICs) funded by the National Institute of Allergy and Infectious Diseases (NIAID). The goal of this work is to evaluate promising next generation influenza vaccine candidates in Phase I and Phase I/II clinical trials and human challenge studies. He is also the Duke Principal Investigator for the CDC-funded Clinical Immunization Safety Assessment Project which conducts studies to identify risk factors and preventive strategies for adverse events following immunization, particularly in special populations. Lastly, he is the Principal Investigator for the CDC-funded coordinating center of the influenza and other respiratory virus vaccine effectiveness network. This work provides national estimates for influenza and other respiratory virus vaccine effectiveness in persons presenting with respiratory illness in the ambulatory setting.
Dr. Walter's focused area of interest include vaccine development, vaccine safety, vaccine effectiveness, vaccine coverage, prevention and treatment of infectious diseases.
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