Editor's note: PATH is co-hosting the 7th International Conference on Microneedles on May 15-17, 2023, in Seattle, Washington. Registration is now open, please visit the conference website or email MAPs@path.org with any questions.
Imagine opening your mail to receive a vaccine instead of traveling to a health clinic. The vaccine can be administered at home because it requires no refrigeration, no needle, nor the assistance of a highly trained health expert. This kind of future, while still years off, could be possible with the development of microarray patches (MAPs).
MAPs consist of microscopic projections that are applied to the body like a small adhesive bandage, painlessly penetrating the skin to deliver vaccines and medicines that protect against life-threatening diseases.
These groundbreaking patches could reduce illness and death for billions of people by making vaccines, as well as other essential medicines and diagnostics, easier to transport, store, and deliver. But scaling up MAP technology is a highly complex endeavor that will require significant technical effort, funding, and political will.
How MAPs address key shortcomings of current, injectable vaccines
While current, injectable vaccines have been immensely effective in inoculating people against deadly pathogens, the way they must be transported, delivered, and administered can pose obstacles to widespread vaccine accessibility. MAP technology addresses several of these obstacles by enabling:
Simplified logistics and transport. Many vaccines need to be kept between 2°C–8°C during their transport through the “cold chain”—from the manufacturing line all the way to health clinics around the world. Currently, some mRNA COVID-19 vaccines need to be stored at extremely cold temperatures (–70°C), which is costly and can limit the number of locations where the vaccine can be delivered and stored. In contrast, a MAP formulation could be designed to enhance stability of the vaccine.
“Certain MAPs could be stored at room temperature for a few days or weeks, which has enormous implications for supporting faster distribution and more equitable access to vaccines.”— Courtney Jarrahian, Co-director, MAPs Center of Excellence
Less vaccine antigen needed per dose. Unlike vaccines that are delivered into the muscle or subcutaneously (in the tissue layer under the skin)—such as the current COVID-19 and measles-rubella vaccines—MAPs deliver vaccine into the skin. Not only is this method less painful, but it might also create a stronger immune response with less vaccine. This could ultimately accelerate the uptake of vaccines since a limited amount of vaccine antigen could be used to vaccinate more people.
More delivery settings. Setting up mass vaccination programs to rapidly vaccinate vulnerable populations can be a logistical challenge, from finding trained staff to deliver injections to maintaining safety and accuracy during vaccination campaigns. Since MAPs are easy to apply, they could be distributed in new ways, such as door-to-door household delivery by community health workers, rapid vaccination via drive-through clinics, or by mail in conjunction with a telemedicine appointment.
Put simply, MAP technology has the potential to address limitations of current vaccines and to facilitate more equitable and efficient access to vaccines.
Making MAPs a reality
Recognizing the enormous possible impact, PATH has been partnering with public health agencies, MAP developers, manufacturers, and pharmaceutical companies for more than a decade to assess and advance MAP delivery technology for a variety of global health applications.
The PATH Center of Excellence for Microarray Patch Technology facilitates the advancement of MAPs technology to increase access to critical vaccines and essential medicines to meet global health needs and to improve equity. It has identified six high-potential areas for developing MAPs products: the measles-rubella vaccine, hepatitis B birth dose for infants, rabies vaccine, human papillomavirus vaccine, hormonal contraception, and long-acting antiretrovirals for HIV.
MAPs are also one of the three high-priority innovations identified through the Vaccine Innovation Prioritisation Strategy, a partnership between Gavi, the Vaccine Alliance; the World Health Organization (WHO); the Bill & Melinda Gates Foundation; UNICEF; and PATH. One vaccine MAP of high interest is measles-rubella (MR), which was prioritized by the WHO Strategic Advisory Group of Experts on Immunization in 2016. An MR MAP could increase vaccine access, facilitate virus elimination and ultimate eradication, and improve health—particularly for children in poor and difficult-to-reach communities where MR vaccine coverage is lowest. Two leading MAP developers are currently conducting Phase 1 clinical trials.
“Such MAP applications could ensure that people in low-resource settings could access lifesaving vaccines and essential medicines more easily and efficiently, a functionality that is frequently requested by stakeholders.”— Jennifer Foster, Senior Technical Officer, MAPs Center of Excellence
But to make the widespread application of MAPs a reality, stakeholders—especially from the private sector—need to pledge support in three key areas:
1) Accelerating development of the MAP platform to bolster evidence that MAPs work and can be used with various vaccines and essential medicines.
2) Developing manufacturing capacity to enable larger scale clinical trials, validation of the manufacturing process, and regulatory approvals.
3) Securing commitments from private-sector partners to provide the vaccine (or antigen) for testing and to participate in building the manufacturing, clinical, and regulatory pathways.
This support requires significant, coordinated technical resources, financial investment, and political will from stakeholders, but—according to Jessica Mistilis, Senior Manufacturing Engineer at the Center of Excellence for MAP Technology—two key obstacles currently stand in the way.
First, despite strong excitement about the technology, the development of safe and effective MAPs for global markets could take up to a decade—if not more.
“Mass production of MAPs takes time because it requires the invention of highly complex manufacturing equipment that can precisely form and/or coat the microscopic needles at very high speeds, while ensuring the safety and quality.”— Jessica Mistilis, Senior Manufacturing Engineer, MAPs Center of Exc.
It can take several years to conduct the clinical trials for each new vaccine or medicine, which are required to demonstrate efficacy and safety to regulatory authorities.
Second, MAPs are a disruptive technology, meaning they have the potential to replace entrenched technologies and systems that have already been researched, funded, developed, and used for decades. Despite strong interest, pharmaceutical companies and other stakeholders may be hesitant to invest in long-term research and development for a novel technology when technologies and systems for delivering vaccines and medicines inexpensively already exist.
A promising tool for pandemic response
Mobilizing efforts to address these obstacles has real-life implications for improving global health. As the COVID-19 pandemic has so clearly illustrated, vaccine inequity has a direct impact on the severity and duration of a pandemic. Ongoing challenges with manufacturing, shipping, storing, and administering the COVID-19 vaccine in low-resource settings have contributed to widening gaps in vaccine access and long-term effects of the pandemic.
“MAPs could potentially avoid logistical challenges because they are simpler to transport, store, and administer.”— Darin Zehrung, Co-director, MAPs Center of Excellence
Rapidly deploying vaccines through MAPs could help prevent or reduce the impact of an epidemic or pandemic, and investments in advancing MAPs for COVID-19/pandemic applications are underway. The Beyond the Needle program at the US Biomedical Advanced Research and Development Authority (BARDA), for example, is focusing on MAPs and their potential to transform health security.
Despite investment in research on MAPs, the potential for large-scale use of vaccine MAPs is still years away. Making MAPs a reality requires additional focus and resources from both the public and private sectors. By prioritizing investment in manufacturing facilities and close cross-sector collaboration, the global community can accelerate access to this promising technology.
To learn more about how you can support the development of MAPs to improve vaccine equity, reach out to the PATH Center of Excellence for Microarray Patch Technology at MAPs@path.org.