Scientists are creating next generation vaccines that are contagious

What if you never got ill again? Ever. I’m not talking about not getting Cancer, although there is a new vaccine being trialled for that in China, I’m talking about what if you never had to get any of those illnesses that cause you to take days off work, like the flu? Or the measles… but unlike today’s world where you avoid getting some of those diseases because you’ve been to the doctors to get vaccinated, what if you were ‘just immune.’

In today’s world being protected against infectious diseases without ever having to get vaccinated might at first sound like a magic trick, but magic tricks, or science fiction to give it another name, has a habit of becoming science fact and those things that years, decades or even centuries ago first looked like magic, well, let’s face it, as readers of my blog know probably better than anyone else, they become part of our every day.

Today’s vaccines are incredible – they’ve been used to eliminate Smallpox, purge Ebola and Rubella and saved millions of people dying each year from Diptheria, Tetanus and Whooping Cough, to name just six.

Thanks to a phenomenon known as Herd Immunity, we all know that when enough people get vaccinated infectious diseases have a much harder time spreading. But often it’s hard to reach enough people, particularly in rural and remote locations, to get this phenomenon to kick in, so scientists are now taking a leaf out of the virus’ own playbook and they’re starting to develop vaccines that spread from one host to another. In other words – they’re creating vaccines that are contagious, and that could be a game changer.

While it’s early days for these kinds of vaccines, and inevitably there’s a long road ahead, because to begin with scientists have to be able to demonstrate that these new vaccines will be safe to use in the wild, the new strategy would certainly be more effective than today’s where everyone lines up be stabbed with a needle, and it could be cheaper, and far more effective at preventing disease too. And all of that sounds like it could be a win…

So far there are three main techniques that are being trialled and developed. The first is to create a weakened, but live, version of the virus vaccine that can spread briefly before it dies out, but there is a drawback. Rarely, the live vaccine can mutate enough to revert back to its virulent form. The oral Polio vaccine, for example, contains three strains of the virus, one of which has been eradicated in the wild but which is also most likely to cause the most problems.

“Most vaccine designs don’t consider transmission,” says James Bull, an evolutionary biologist at the University of Texas at Austin.

“[and] if we did intentionally design transmissible vaccines, they might be more likely than regular vaccines to revert. That’s because they reach more people and have a chance to replicate and make new generations. That means more chances for mutations and evolution. Then your transmissible vaccine turns back into the disease effectively,” adds Scott Nusimer, a mathematical biologist at the University of Idaho in Moscow who’s collaborated with Bull in the past.

One way around this would be to make a live vaccine that is only weakly transmissible. This vaccine would only spread a little bit before dying out. In this case this kind of vaccine wouldn’t be able to eradicate a disease, but fewer people would need to be directly vaccinated and it would still make a serious dent in any outbreaks.

“Even a little bit of transmission goes a long way,” says Nusimer, “and we would save a lot of money. If we had a transmissible version of the Measles, Mumps, and Rubella (MMR) vaccine, we could bring down the cost of immunisation by roughly $50 million per year. It’s astronomical the amount of money you would save, even with a weakly transmissible vaccine.”

Fundamentally though it’s also likely that scientists could also genetically engineer a live vaccine in new ways, for example, using powerful Gene Drives, that could thwart its ability to evolve into something nasty.

The second technique, which could, for example, be used to vaccinate bats that carry the Ebola virus, uses transmittable vaccines that target animals and humans that are already ill using benign viruses, such as Cytomegaloviruses (CMV), which are already carried by up to 80 percent of the US human population without any side effects, that can infect an animal or human without making them sick, or at least sicker.

In this kind of vaccine the live CMV’s would be engineered to carry a tiny fragment of another, disease causing virus that the immune system would recognise and attack, and should that virus revert, it would simply lose its effectiveness as a vaccine. Furthermore the vaccine could also be stripped of the genetic instructions that enable it to replicate.

“It doesn’t have any disastrous consequences because it just goes back to being a cytomegalovirus,” says Nusimer.

“The next stage is to determine whether immunity from a self-disseminating version of the vaccine provides protection,” Jarvis says, “with CMV’s, nature and evolution has done your work for you as these viruses have evolved to spread easily.”

Finally, and the third technique that scientists are investigating, which is catchily called “Therapeutic Interfering Particles,” or TIPs, gives viruses a taste of their own medicine so to speak and scientists are designing debilitated, transmissible viruses that, unlike vaccines, are intended for people who are already infected, and that acts like a parasite.

An example here could be a new viral vaccine that’s used to treat HIV, in this example the new vaccine would enter all the cells that are infected with HIV and compete with HIV directly for the cells resources, ‘starving’ HIV’s ability to gain the resources it needs to grow and replicate. However, in this case scientists think that new TIPs vaccines could unwittingly start a new viral arms race where HIV tries to mutate to one up the new vaccine, and that could be a bad thing…

However, and if all else fails then we’ll just have to thank our lucky stars that we’ve already been able to create new genetic organisms that are naturally already resistant to every known virus on the planet – and one day, who knows, maybe we’ll be able to genetically engineer artificial humans that can do the same… but that’s all sci fi drivel and that would just be stupid. Or would it…?