Dr. Kathleen Neuzil

Typhoid may seem like a distant memory in industrialized countries, but for many low- and middle-income countries (LMICs) it continues to cause millions of illnesses and about 150,000 deaths per year in endemic areas and during outbreaks. Spread through contaminated food and water, typhoid typically burdens young children and adolescents under the age of 15. Recently, we have witnessed several outbreaks, including those in Zimbabwe,  Zambia, and Pakistan, where thousands of typhoid cases have been reported. Without treatment, typhoid can cause serious short- and long- term complications, and even lead to death. While antibiotic treatment has greatly improved outcomes in typhoid patients, the effectiveness of antibiotics is becoming increasingly limited. The World Health Organization (WHO) has called antibiotic resistance one of the biggest threats to global health today, and treating typhoid is no exception. Drug and multi-drug resistant typhoid has been increasingly reported in LMICs in Southeast Asia and sub-Saharan Africa where typhoid burdens are highest, and treating drug-resistant typhoid may become prohibitively expensive. As global experts met this week at the International Caparica Conference in Antibiotic Resistance to discuss ways to address this growing issue, I reflected on ways that we can combat this looming threat for typhoid: 1. We need to accelerate the introduction of typhoid vaccines alongside proven water, sanitation, and hygiene (WASH) interventions. Just as we know how to treat typhoid, we also know how to prevent it: WASH precautions are key. However, given the significant burden of typhoid among hard-to-reach populations where WASH progress may be slow, we need an integrated approach to prevention that includes vaccines. Currently, two vaccines are globally available and are effective in preventing typhoid—an oral live attenuated vaccine and an injectable Vi capsular polysaccharide vaccine. In 2008, WHO recommended that both vaccines can be used during outbreaks and in endemic areas, but uptake has been low and neither are used routinely. Newer typhoid conjugate vaccines (TCVs) have the potential to overcome the shortcomings of the current vaccines by allowing for longer-lasting protection, fewer doses, and greater suitability for children younger than two years old in routine childhood immunization programs. The Typhoid Vaccine Acceleration Consortium (TyVAC), a partnership between the Center for Vaccine Development at the University of Maryland School of Medicine, the Oxford Vaccine Group at the University of Oxford, and PATH, an international nonprofit, is committed to ensuring that prevention and control of typhoid is a global health priority. We work with local and global partners to accelerate the introduction of TCVs in LMICs as part of an integrated prevention strategy. 2. We need research and development to advance the typhoid vaccine, drug, and diagnostics pipeline to prevent, accurately diagnose, and treat typhoid. One of the challenges of typhoid is that an infected person presents with symptoms that are often mistaken for other diseases, which leads to frequent misdiagnoses. Current diagnostics require blood or bone marrow and a lab to analyze the results, which is not feasible for many low-resource health facilities. Knowing that a patient has confirmed typhoid allows the physician to provide the proper course of treatment and helps combat antibiotic misuse. A robust vaccine and drug pipeline will help ensure that we continue to have a range of prevention and treatment tools at our disposal for typhoid. There are currently several TCVs in various stages of development. New vaccines provide a mechanism for protection against typhoid that can avert cases that may be drug resistant. As more vaccines and drugs become available, access improves and costs can come down due to healthy market competition. The time is now for us to #TakeonTyphoid. We cannot afford to risk typhoid becoming untreatable—not when we can strengthen prevention through immunization with TCVs and improvements in WASH.