Enteric and Diarrheal Diseases

We focus on advancing the development and delivery of vaccines to combat these diseases, which disproportionately affect children in lower-income settings. Our efforts include investments in vaccines for rotavirus, the most common pathogen that causes moderate to severe diarrhea, and the leading bacterial causes of diarrheal diseases, Shigella and cholera. We also focus on typhoid, a disease affecting populations with less access to safe sanitation, clean water, and medical services.

Rotavirus. Rotavirus is the most common cause of diarrheal hospitalizations and deaths in children under age 5 in lower-income countries. Existing rotavirus vaccines have been shown to dramatically reduce the number of hospitalizations and deaths. The World Health Organization (WHO) recommends their use in all countries, particularly in places where diarrhea is a major cause of child mortality.

We work closely with Gavi, the Vaccine Alliance, and national governments to support the introduction and sustainable delivery of rotavirus vaccines in all infants globally and to ensure adequate supply and appropriate formulations, packaging, and labeling.

We also work with vaccine manufacturers in emerging economies such as India and Indonesia to invest in new oral rotavirus vaccines that will diversify the market, increase vaccine supply, and decrease costs.

Despite the success of current rotavirus vaccines, their effectiveness is often lower in low-resource settings than in middle- and high-income countries. The reasons include a condition called gut enteropathy that is associated with multiple other enteric infections, inflammation and malnutrition, high maternal antibody levels, and the microbiome. We are working with several partners to develop next-generation rotavirus vaccines that are more effective and can help increase vaccine access in low-income settings.

Cholera. Cholera kills as many as 120,000 people each year. At least 47 countries in sub-Saharan Africa and Asia have endemic cholera, which means the disease is consistently present. Several recent outbreaks in Nigeria, Yemen, South Sudan, Zimbabwe, Cameroon, and elsewhere have severely strained these countries’ under-resourced health systems. For example, in 2021–2022, Nigeria experienced a surge in cholera cases, with thousands of cases and many deaths, highlighting the largest peak in disease in over a decade and showing the potential impact of outbreaks in endemic settings. A cholera outbreak in the Democratic Republic of the Congo between 2013 and 2017 resulted in more than 3,300 deaths. Simultaneous outbreaks of measles and Ebola overwhelmed the country’s health system, demonstrating the importance of strong health systems that reach communities quickly with lifesaving tools such as oral cholera vaccines.

With support from our foundation and other international partners, WHO established a global oral cholera vaccine stockpile in 2013, which is managed by Gavi—a key milestone for cholera prevention and control. The Global Task Force on Cholera Control has facilitated the shipment of more than 100 million doses of cholera vaccine to more than 26 countries for use during outbreaks and humanitarian crises and in endemic areas. The cholera vaccine supply remains insufficient, however, so we support additional vaccine manufacturers in emerging economies in producing more. Stable vaccine supply should lead to more competitive pricing and spur additional demand from countries with a high burden of cholera. Several countries have implemented successful cholera vaccination campaigns and expanded their requests for additional doses in subsequent years.

We also support the development of evidence-based policy guidelines for oral cholera vaccine use in outbreak settings, as well as better data collection to build a case for the targeted use of cholera vaccines in endemic or “hot spot” areas.

Typhoid. Every year, typhoid infections kill nearly 100,000 people, primarily children in lower-income countries. In recent years, cases of antibiotic-resistant typhoid have increased, making the disease even more dangerous.

Typhoid conjugate vaccines (TCVs) offer a solution. First developed in 2015 with our support, these vaccines are a game-changer for preventing the spread of typhoid. They are the first typhoid vaccines to be approved for use in children under age 2—one of the groups most vulnerable to typhoid. They also provide long-lasting immunity and reduce the need for antibiotics, which helps prevent drug-resistant strains of typhoid from emerging and spreading. TCVs were developed and are now manufactured in South Asia and Southeast Asia, where the burden of typhoid is greatest.

More than 36 million children have already received a dose of TCV, and the results have been promising and remarkably consistent: Studies have shown that TCVs can prevent 80% or more of typhoid cases. The vaccine has been included in routine childhood immunization programs in countries including Pakistan, Liberia, and Zimbabwe, and more countries are planning to introduce the vaccine soon. TCVs are helping us get closer to a world where no child dies from a vaccine-preventable disease.

Shigella. Shigella is a common bacterial pathogen in most low-income regions, with more than 93,000 deaths in children under age 5 in 2019. Shigella infection is also associated with significantly reduced growth. Due to its growing resistance to multiple drugs, therapeutic options are limited, which makes developing a vaccine a high priority.

No vaccine is currently available for Shigella, but we are working with public health partners, biotechnology companies, and in-country vaccine manufacturers to accelerate the development process, including investing in early-stage candidates and analytical tools.

We support several surveillance networks, including for global pediatric diarrheal disease surveillance through WHO and its regional offices, typhoid surveillance in South Asia and Africa, and the Child Health and Mortality Prevention Surveillance (CHAMPS) network, a global network of foundation-funded study sites.

We also invest in the development of affordable tools to assess disease burden, such as environmental surveillance, and we work with partners to model data to ensure their translation into rapid public health action. For example, we work with researchers at Imperial College London and partners at the Christian Medical College in Vellore, India; Malawi Liverpool Wellcome Trust in Blantyre, Malawi; and Kwame Nkrumah University of Science and Technology in Kumasi, Ghana, to validate environmental surveillance tools for typhoid alongside clinical surveillance. More recently, building on these efforts, our partners have implemented SARS-CoV-2 surveillance and environmental surveillance of multiple respiratory and enteric pathogens using a promising low-cost platform for enhancing outbreak and pandemic preparedness.

Our efforts include supporting the goals of the integrated Global Action Plan for Pneumonia and Diarrhea and the Immunization Agenda 2030. Our core partners in this work include Gavi, UNICEF, WHO, PATH, the International Federation of the Red Cross, and Save the Children.