Measles is considered one of the world’s most contagious diseases and continues to pose a significant global health risk. In fact, any community where vaccine coverage rates are below 95 percent is at risk of an outbreak.
The two-dose measles-containing vaccine is 97 percent effective at preventing measles. Vaccination, especially in children under age five, is key to protecting individuals and preventing outbreaks within communities, particularly in low- and middle-income countries.
Ensuring vaccine efficacy requires years of meticulous planning, including carefully regulated cold storage, transportation and administration. The measles vaccine relies on a "cold chain," a temperature-controlled delivery system to keep it safe and effective at every stage. This makes a vaccine's journey from a manufacturing plant to its destination, often on the other side of the world, complex and expensive.
In recent years, the COVID-19 pandemic, staffing shortages at vaccination sites and disruption of the cold chain have caused problems in vaccine distribution, especially in areas where limited access to electricity makes refrigeration difficult or impossible. These factors have contributed to an overall decline in measles vaccination. In 2023, nearly 35 million children missed at least one lifesaving measles vaccine dose.
A cold cargo container with vaccines is loaded onto an airplane.
Healthcare workers carry small fridges filled with vaccines. This is often the only solution for delivering vaccines to remote parts of the world.
In the absence of a global infrastructure to store, transport and administer vaccinations, disease protection and eradication has become even more difficult. It is the role of public health to address barriers and seek innovative solutions, and in the case of the measles vaccine, an innovative solution is on the horizon.
The Measles Rubella Microarray Patch
The measles and rubella microarray patch (MR-MAP) is a sticker roughly the size of a silver dollar coin and coated with microscopic needles that painlessly penetrate the skin to deliver the vaccine in just five minutes.
Because they require little or no refrigeration, MR-MAPs are easier both to transport and deliver, since volunteers, who could have little to no medical expertise, can be quickly trained to apply the patches. Since the MR-MAP's microneedles dissolve after use, their design eliminates the risk of needlestick injuries, which the World Health Organization estimates cause 39 percent of hepatitis C infections, 37 percent of hepatitis B infections and 4.4 percent of HIV infections globally.
“The MR-MAP vaccines have the potential to save lives,” said Dr. Stephen Crooke, Vaccine Immunology Lead in the Division of Viral Diseases at CDC. “Without access to measles and rubella vaccines, thousands of children will die or be born with severe birth defects due to these infections. Knowing that this technology has the potential to prevent that and could provide these children the chance at a healthy life is an exciting prospect.”
A child is administered the MR-MAP as part of the phase 1/2 trial in The Gambia.
The microarray patch before it is administered.
With support from the Bill & Melinda Gates Foundation, researchers at the Centers for Disease Control and Prevention (CDC), Micron Biomedical Inc., the Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine (LSHTM) and the CDC Foundation have just wrapped up a phase 1/2 trial of the MR-MAP in The Gambia, in West Africa. In the trial, over 90 percent of infants were protected from measles, and 100 percent were protected from rubella. More importantly, the immune response from the MR-MAP was shown to be comparable to that of the injectable vaccine.
The MR-MAP vaccines have the potential to save lives.
“By improving vaccination coverage among children in hard-to-reach populations, you could close immunity gaps and reduce the overall incidence of measles on a global scale,” explained Dr. Crooke. “This would bring us closer to achieving our worldwide measles elimination goals and could result in thousands of deaths averted.”
While the results have been promising, this technology must go through more trial phases before it can be scaled up. Microarray patches have been listed as a priority innovation by Gavi, the Vaccine Alliance, a global leader in protecting lives through vaccinations. We are excited about the future promise of this technology, and are continuing our work in evaluating the vaccines–likely including phase 2 trials in The Gambia next year. According to Dr. Crooke, “The next 5-10 years are going to be very exciting.”
Photos courtesy of MRC Unit The Gambia at LSHTM and UNICEF.