It may sound far-fetched, but vaccines that are designed to spread from one individual to another, much in the same way that viruses do, instead of needing to be injected into each person, are in the works. It means that governments would only need to persuade a small percentage of the population to get vaccinated, and then everyone else would essentially “catch” the vaccine as it spreads throughout the population via airborne droplets in the same manner that colds and flu spread.
Development is proving challenging, however, as making a transmissible vaccine requires determining a way to package a virus or bacteria so it can be transmitted easily from one individual to another without causing them to become seriously ill.
One approach being explored is engineering a very mild form of whatever virus scientists wish to protect against in a lab, making sure it is contagious enough to infect a significant proportion of the population quickly enough that most people’s immune systems will start producing antibodies that can fend off the virus. However, it must be weak enough to avoid causing the health effects of the full-strength virus.
Another option is packaging some DNA from the dangerous pathogen scientists are targeting inside a highly contagious yet relatively harmless existing virus, such as the virus that causes the common cold.
It’s an approach that has already been tested on rabbits in Spain in 2000. Researchers injected 70 rabbits with a transmissible vaccine and then returned them to the wild. Those rabbits quickly passed the transmissible vaccine on to hundreds of other rabbits, which put an end to a deadly virus that had been affecting their population. In other parts of Europe, similar techniques are being tested using pigs to stem the spread of African swine fever.
There are lots of reasons to be wary of such an approach. While proponents claim it can provide protection to a lot of people in a short amount of time and reduce the number of vaccine doses that need to be produced, it is important to keep in mind that, like all vaccines, self-spreading vaccines still have the power to kill people. A 2019 paper from the UK’s Department of Health and Social Care said that with such vaccines, “Some people will die who would otherwise have lived, though fewer people die overall.”
This brings us to one of the biggest problems with the vaccine: The majority of patients who ultimately receive it will not have given their consent. Unfortunately, there is already precedent for this sort of thing. For example, fluoridating drinking water can help prevent tooth decay, and it’s been done to many Americans’ water without their consent, putting them at risk of other health problems connected to fluoride and denying them of the freedom to make their own risk-versus-reward assessment.
There is also the potential for weakened viruses to mutate into more potent forms when they are free to spread among the population. Moreover, the science used in self-spreading vaccines could be hijacked by nefarious individuals or groups to create biological weapons. Even testing these types of vaccines has the potential to put an end to mankind given how quickly they are designed to spread. It's absolutely terrifying to think of all the ways that self-spreading vaccines could possibly go wrong.
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