Scientists Propose ‘Tattoos’ To Solve Vaccination Issues

According to Wikipedia, the widespread use of vaccinations has “greatly reduced the incidence of many diseases in numerous geographic regions,” a fact most people already know. But tracking who’s received vaccinations and which ones remains a daunting task for medical professionals, especially when it comes to keeping tabs on children. Now, a group of MIT researchers funded by the Bill & Melinda Gates Foundation says that invisible tattoos may be the best way to deal with this tracking issue, although there are some ethical concerns with their proposed solution.

In a paper recently published in the journal Science Translational Medicine (via Futurism), the group of researchers, led by Kevin J. McHugh et al., says that it is exploring a novel approach for maintaining accurate vaccination records by testing the implantation of “near-infrared quantum dots,” or NIR QDs, into pig skin, rat skin, cadaver flesh, and synthetic human skin. NIR QDs are water-soluable, biocompatible fluorescent nanocrystals—with diameters ranging from 2 to 10 nanometers—that emit near-infrared light and are safe for deep tissue insertion. As of right now, researchers are exploring NIR QDs for numerous medical uses, including, most notably, in vivo tumor imagining.

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An illustration of how the NIR QDs would be applied and read. Kevin McHugh / Rice University 

In the case of vaccinations, the plan is to inject NIR QDs concurrently with a given vaccine via a small patch of partially dissolvable microneedles. (The video below offers a demonstration of this process on synthetic human skin.) After insertion into a person’s skin, the NIR QDs would then continuously emit a wavelength of light not visible to the human eye, but easily imaged by certain types of cameras. This would effectively imprint a kind of invisible tattoo on people who receive vaccinations, identifing them as already inoculated. The NIR QDs used in this particular study were readable with a modified smartphone aided by machine learning algorithms.

The researchers say that they could read NIR QDs nine months after initial injection into rat skin, and resisted photobleaching even after receiving the simulated equivalent of five years of exposure to sunlight. The researchers also found that the NIR QDs didn’t interfere with the efficacy of the vaccines they accompanied, and they can easily customize their injection patterns in order to label or distinguish between different types of vaccinations.

This method of injecting invisible tattoos along with immunizations could potentially address the challenge of keeping accurate vaccination records in poorer countries, where centralized medical databases are hard to create or maintain. According to the researchers, if this method does indeed prove itself to be effective, it could eventually help to mitigate the 1.5 million vaccine-preventable deaths that occur each year. This would be particularly critical for children, who are especially susceptible to infectious diseases thanks to their relatively underdeveloped immune systems.

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A look at the partially soluble patch of microneedles. Kevin McHugh / Rice University

Looking forward, these researchers would like to survey health care workers in various developing countries in Africa, with the intent of gaining insight into the most effective way to implement this kind of tattooed record keeping. But there people who are wary of this method of invasive record keeping, like Grace Lee, an infectious disease pediatrician at Stanford University’s Lucile Packard Children’s Hospital. Lee, who wasn’t involved in the research, told Smithsonian Magazine that this kind of record keeping could potentially lead to confusion, as the NIR QDs could be misapplied, or misread thanks to their fading over time. Lee also told Smithsonian that this kind of on-the-body record keeping could lead to privacy concerns and discrimination, which could potentially render the benefits of the invisible on-the-body vaccination records totally moot.

A video of the soluble patch of microneedles containing the NIR QDs being applied to synthetic skin. 

What do you think about this method of using invisible markers to keep track of who and who hasn’t been vaccinated? Is this a brilliant way to save tons of lives in developing countries, or just a frightening invasion of privacy? Let us know your thoughts in the comments!

Feature image: Kevin McHugh / Rice University