The endgame to the COVID-19 pandemic requires the identification and manufacture of a safe and effective vaccine and a subsequent global immunization campaign. However, the vaccine supply chain is complicated by the requirement for cold chain distribution logistics and sufficiently trained vaccinators to administer the vaccine by injection. This complicated supply chain adds to the cost and delays full global roll-out of a pandemic vaccine resulting in delayed and inequitable vaccine coverage.
We have been addressing this problem by creating an easy-to-administer skin patch that thermostabilizes vaccines. As vaccine administration only requires placing the patch on the skin, we have removed the need for needles, syringes, biohazardous waste and training of healthcare workers. Ease-of-administration is critical to ensure cost-effective, high vaccine coverage and disease eradication, as evidenced by the success of the oral polio vaccine. The patch format stabilizes the vaccine out of cold chain conditions, thereby simplifying vaccine distribution and logistics. Skin delivery of thermostabilized vaccines therefore presents several advantages compared to intramuscular delivery, including increased compliance due to simplicity of vaccination, broadening the profile of the immune response and the potential for dose sparing.
Here, we will discuss our previous work on developing these skin patches, which use dissolvable microneedles to stabilize vaccine in the solid state and deliver it into the body. We will discuss our previous work on incorporating different vaccine platform technologies into these skin patches, including adenovirus virus vectors, lipid-based, nucleic acid-based and subunit vaccines, which are the leading platforms used in successful COVID-19 vaccines.