Implications and measurement of herd protection (indirect effects) for enteric vaccine development.

Diarrhea remains one of the top five causes of disease and death among young children in developing nations. Fortunately, scientists are making progress developing vaccines against enterotoxigenic E. coli (ETEC) and Shigella, two of the leading diarrhea pathogens. As vaccine developers start to consider field efficacy trials of these vaccines, they should be aware of the importance of evaluating not only vaccine direct effects on the immunized, but also the herd effects that vaccination can afford to the unimmunized in a community. In a workshop held at the conference titled "Vaccines against Shigella and ETEC (VASE)", we described to participants what herd effects are and we presented on methods used in cholera and rotavirus studies that could be useful for future ETEC and Shigella vaccine trials conducted in low and middle-income nations. We also presented evidence on the effects of vaccine herd effects for estimates of vaccine cost-effectiveness.

Using advocacy to increase investment in enteric vaccine development.

Catalyzing and sustaining momentum for long-term research investments can be a challenge, especially for enteric pathogens like ETEC andShigella that are most threatening to the health of children in low-resource areas, and whose vaccines would not be for global use. The 2018 Vaccines Against Shigella and ETEC (VASE) Conference included a workshop focused on building the capacity of scientists to communicate about their own research and advocate for additional attention and funding for enteric disease and vaccines research. Workshop presenters shared best practices and examples of advocacy, communications, and messaging tactics that have been used successfully during early stages of vaccine development research for other pathogens. The presentations were followed by an interactive, hands-on training for real-life communication opportunities for scientists that could result in increased research funding, including developing resonant messaging for relevant audiences and practicing interviews.

Development of a travelers' diarrhea vaccine for the military: how much is an ounce of prevention really worth?

Infectious diarrhea is one of the many threats to the deployed military, and given limited resources, a decision to pursue a vaccine acquisition strategy should be based on best evidence that weighs costs and benefits compared to alternatives. An economic model was developed to estimate the marginal cost to avert a duty day lost due to diarrhea for a vaccine acquisition strategy compared to current clinical management, for both multiplex and pathogen-specific vaccines. Vaccines against Campylobacter and enterotoxigenic Escherichia coli appeared to be more favorable than a Shigella vaccine. This model provides an evidence-based decision tool to support prioritization in vaccine development.