We know that typhoid conjugate vaccines, in combination with improvements in water, sanitation, and hygiene (WASH), are effective tools for typhoid prevention. However, ensuring equitable vaccine access requires innovative approaches, especially in resource-limited settings where additional barriers exist. For example, traditional vaccine delivery–using a needle and syringe–depends on a cold-chain and trained vaccinators. In addition, partial contents of multidose vials are often wasted as they expire soon after a first dose is drawn.
Vaccine Microarray Patches (MAPs) are an example of a new vaccine delivery method that uses tiny projections coated with a dried vaccine formulation to deliver the vaccine to immune cells under the skin. This needle-free technology has significant potential to impact typhoid control and human health.
SK bioscience, a global vaccine and biotech company, and Vaxxas, an Australian biotechnology company, recently announced their partnership to develop a new high-density microarray patch (HD-MAP) for typhoid conjugate vaccine (TCV) administration. This partnership combines SK bioscience’s recent advance in developing SKYTyphoid™ TCV with Vaxxas’ unique patch technology. Based on favorable safety and immunogenicity results from clinical trials, SKYTyphoid™ TCV is expected to obtain World Health Organization (WHO) prequalification this year.
This HD-MAP is complementary to traditional vaccine delivery. Benefits of HD-MAP vaccine products include (1) the potential for an increased immune response with fewer doses, (2) no cold chain requirement, (3) a single-dose presentation, (4) less waste since there is no syringe nor glass vial, and (5) they can potentially be administered by a parent or teacher instead of only trained healthcare workers, all of which are critical factors in making vaccines more accessible for hard-to-reach populations in limited-resource settings.
For TCV, already a single-dose vaccine, a HD-MAP may open new options for reaching children in schools or reaching more remote communities where carrying cold boxes, syringes, and other vaccination supplies can be a limiting factor.
The HD-MAP TCV will undergo preclinical studies followed by a Phase I clinical trial. The project is expected to be completed within two years. Adding this innovative technology to the global toolkit will help address issues of vaccine storage, distribution, and accessibility, which offers hope that typhoid vaccines can reach even more high-risk populations. In the meantime, the two current WHO-prequalified TCVs will likely soon be joined by a third, increasing global TCV availability. Decision-makers should continue to prioritize the current WHO-recommended TCVs–to take on typhoid–while novel approaches to vaccine delivery are underway.
Cover photo credit: PATH.
