Measles and polio vaccination using a microneedle patch to increase vaccination coverage in the developing world

Abstract

Despite the existence of effective vaccines for both diseases, measles and poliomyelitis still cause significant worldwide morbidity and mortality. The live-attenuated measles and inactivated polio vaccines are both given using a standard needle and syringe injection. This method of delivery poses many problems for large-scale vaccination campaigns. Microneedles are micron-scale needles which have the potential to overcome many of these hurdles. In the first study, we showed that the measles vaccine could be successfully incorporated into a solid, metal microneedle system which induced potent neutralizing antibody titers after administration into cotton rats. This response was statistically identical to the same dose delivered using a subcutaneous injection. The second study focused on enhancing the stability of the measles vaccine after drying and long-term storage. Using a new assay developed from a measles virus variant engineered to encode for green fluorescent protein, it was determined that a combination of sucrose and threonine provided the highest stabilizing effect. Vaccine mixed with this solution retained more than 90% of its activity after 6 months of storage at 4°C and 25°C. The third study involved the incorporation of the measles vaccine into a dissolving microneedle patch. These patches were used to vaccinate rhesus macaques and the immune response was found to be statistically identical to the same dose delivered by syringe injection. Furthermore, after creation and storage, these patches retained 100% of their infectivity after 2 months at 4°C and 25°C. The final study attempted to create a dissolving microneedle patch containing a full dose of the inactivated polio vaccine. These patches were then used to deliver a full dose of IPV into the skin of a rhesus macaque. This delivery method produced neutralizing antibody titers to IPV type 1 and 2 that were statistically identical to the same dose delivered using a needle and syringe. Overall, these studies show that the microneedle patch was a safe, simple and effective method for measles and polio vaccination. This delivery platform has the potential to overcome many of the hurdles that currently stand in the way of measles elimination and polio eradication.