New typhoid conjugate vaccines offer important advantages over prior vaccines, including the ability to protect young children, longer lasting protection, and the potential to be a part of routine immunization of infants. To accelerate the introduction of these life-saving vaccines, the Typhoid Vaccine Acceleration Consortium (TyVAC), which formally launched at the April 2017 international typhoid conference organized by Sabin, held a meeting in October 2016 to plan typhoid conjugate effectiveness studies that will inform future vaccine policy and financing decisions.

At the October meeting, TyVAC convened a group of typhoid experts, including Sabin’s Vice President of Typhoid Programs, Dr. Denise Garrett, to discuss the design and implementation of TyVAC’s vaccine effectiveness studies. The meeting report, an effort led by Dr. James Meiring from the Oxford Vaccine Group, was recently published in the journal Vaccines. The abstract for the full meeting report is below:

Typhoid fever is estimated to cause between 11.9–26.9 million infections globally each year with 129,000–216,510 deaths. Access to improved water sources have reduced disease incidence in parts of the world but the use of efficacious vaccines is seen as an important public health tool for countries with a high disease burden.

A new generation of Vi typhoid conjugate vaccines (TCVs), licensed for use in young children and expected to provide longer lasting protection than previous vaccines, are now available. The WHO Strategic Advisory Group of Experts on Immunization (SAGE) has convened a working group to review the evidence on TCVs and produce an updated WHO position paper for all typhoid vaccines in 2018 that will inform Gavi, the Vaccine Alliance's future vaccine investment strategies for TCVs.

The Typhoid Vaccine Acceleration Consortium (TyVAC) has been formed through a $36.9 million funding program from the Bill & Melinda Gates Foundation to accelerate the introduction of TCVs into Gavi-eligible countries.

In October 2016, a meeting was held to initiate planning of TCV effectiveness studies that will provide the data required by policy makers and stakeholders to support decisions on TCV use in countries with a high typhoid burden.

Discussion topics included (1) the latest evidence and data gaps in typhoid epidemiology; (2) WHO and Gavi methods and data requirements; (3) data on TCV efficacy; (4) cost effectiveness analysis for TCVs from mathematical models; (5) TCV delivery and effectiveness study design. Specifically, participants were asked to comment on study design in 3 sites for which population-based typhoid surveillance is underway.

The conclusion of the meeting was that country-level decision making would best be informed by the respective selected sites in Africa and Asia vaccinating children aged from 9-months to 15-years-old, employing either an individual or cluster randomized design with design influenced by population characteristics, transmission dynamics, and statistical considerations.

To read the full report, please click here