To improve the lack of vaccination coverage and monitoring in developing countries, researchers have developed a system for implanting a vaccination record under the skin. Visible thanks to a modified smartphone, it would allow doctors to know if a patient is vaccinated against a particular disease.
“Millions of people are still deprived of vaccination coverage” in the world, alert the World Health Organization. However, an unvaccinated person is vulnerable to potentially fatal diseases. Eventually, this can lead to the “re-emergence of previously controlled diseases, the spread of diseases in countries where they had been eliminated and a heavy price that will continue to be paid by millions of people”, writes the WHO.
Also, to better monitor the vaccination of people living in developing countries, where paper vaccination cards are often incorrect or incomplete and electronic medical records do not exist, researchers at MIT have developed a system based on nanoparticles injected under the skin. Thanks to a smartphone, a doctor can therefore check whether the person has been vaccinated or not. This technique, currently only tested on rats, was described on Wednesday December 18 in the journal Science Translational Medicine.
The researchers created copper-based nano-crystals, called quantum dots, 3.7 nanometers in diameter and encapsulated in 16-micrometer microparticles (1 micrometer corresponds to one millionth of a meter and 1 nanometer to one billionth) . Everything is injected through a patch of microneedles 1.5 millimeters in length.
Small dots visible thanks to a modified smartphone
Scientists tested this system on rats. After being applied to the skin for two minutes, the microneedles dissolve and leave small dots under the skin, forming a circle or a cross. If these points are invisible to the human eye, a modified smartphone, pointed at the skin, allows them to appear on the screen. These small dots would be injected at the same time as the vaccine. Thus, years later, a doctor could point his smartphone at someone and check whether the patient has indeed been vaccinated against this or that disease.
While the researchers hope to be able to test their method within the next two years, it will only be useful if it becomes proprietary. Moreover, nothing says that the populations will accept to be marked under the skin for each vaccine. Finally, regarding children, what will happen to the points when they grow up? In order to see more clearly, the Bill Gates Foundation, which funds this work, is conducting opinion polls in Kenya, Malawi and Bangladesh.
The eternal fear of the vaccine
However, some people may refuse vaccines. According to Michel Zaffran, director of the poliomyelitis eradication program at the WHO, like some Westerners, some people in developing countries believe the rumors that vaccines make people sick or are intended to sterilize children, even women. Governments are not helping by mobilizing sufficient human and financial resources. A situation that is all the more complicated since, according to Unicef, 29% of children are not registered at birth, which automatically excludes them from official registers.
“This reflects a lack of prioritization on the part of governments to make vaccination a national and public good”, denounces Michel Zaffran.
In July, the WHO and Unicef presented a worrying report on vaccination coverage in the world. According to their finding, in 2018, nearly 20 million children did not receive vaccines that could prevent deadly diseases, most of them living in poor or conflict-affected countries. “If these children fall ill, they are at risk of serious complications, and are less likely to have access to the treatments and care that would save them,” recalled the WHO at the time.
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