Source: Micron
From the newsletter
The vaccine alliance Gavi is doubling down on developing microarray patches for Africa. This is a form of administering vaccines through a painless patch on the skin. The patches do not require cold storage unlike traditional vaccines, a fact that solves vaccine cold chain challenges across the continent.
Motivated by the vaccine access inequalities during the COVID-19 pandemic, global health partners recommend the patches for hard-to-reach rural areas with unreliable power supply.
One in four health facilities in Africa operate without electricity and while the use of solar energy in hospitals has picked up in the recent past, there are still millions of children missing out on routine immunisation because of broken cold chains.
More details
Microarray patches are small stick-on patches covered with tiny projections that carry a dried form of the vaccine. When applied to the skin, the projections penetrate the outer layer and dissolve. This way, it delivers the antigen to immune cells. Unlike liquid vaccines, the patches remain stable at ambient temperatures for limited periods, reducing dependence on refrigeration.
In April 2025, Gavi and partners published a prioritisation assessment that identified 11 vaccine candidates suitable for microarray patches. They include measles-rubella, hepatitis B, HPV, rabies, yellow fever, COVID-19, seasonal and pandemic influenza and several bacterial diseases.
Clinical development is most advanced for measles-rubella vaccine patches. Phase 1/2 trials conducted in Gambia and reported in May 2023 showed comparable immune responses to injected vaccines in all ages, with no serious side effects.
Additional trials are ongoing for influenza, COVID-19 and hepatitis B patches. In February 2023, Vaxxas launched a Phase 1 influenza patch study in adults, with stability testing showing storage at 40°C for up to 12 months. This indicates reduced cold chain requirements.
Nearly 1 billion people in Africa rely on healthcare facilities that either lack reliable electricity access or have no electricity at all. In Sub-Saharan Africa alone, a total 25,000 healthcare facilities are entirely without electricity, while around 70,000 health centres experience an unreliable electrical supply.
Our take
Vaccine patches are a low-cost method to control future pandemics because of the reduced need for cold chain management and simplified delivery during outbreaks.
Administering vaccines using patches removes the need for syringes and needles, making the process painless. This helps reduce vaccine hesitancy in some communities and lowers costs by eliminating the need to purchase and dispose of injection equipment.