Viral vaccines: the next big step in immunization
The recent Ebola epidemic caused international panic, strict worldwide airport security, and killed more than 11,000 people, leaving researchers scrambling for cheap, efficient, and effective treatments. But it’s not all doom and gloom. Scientists are close to having a vaccine for Ebola and other deadly viruses, and new vaccine technologies, such as viral-vector-based vaccines and RNA vaccines, could soon revolutionize disease prevention.
There are many ways to treat disease. Vaccines are proactive, providing immunity to disease. Vaccines act like a “weakened” form of the disease, causing the body to generate antibodies that prevent illness when the real thing comes along. Vaccination is one of the main reasons why some deadly pathogens have all but disappeared. Take polio, for instance: once widespread, the disease is now rare in the Western world, and the WHO is aiming for a polio-free planet by 2018. Conversely, the unfounded phobia of vaccination has led to recent outbreaks of measles in the United States, Canada, and Mexico, including the highly publicized outbreak at Disneyland, California.
Vaccines work, but they can also have drawbacks. They can be expensive to make, requiring a combination of highly trained scientists, specialized equipment, and loads of funding. Their production can be resource-intensive and wasteful, typically requiring chicken eggs to help incubate the disease pathogens. An egg per vaccine may not seem like much, but hundreds of millions of vaccines are given each year, requiring the production of millions of nutritious eggs. Moreover, producing a vaccine can be slow, much too slow when considering the fast spread of many diseases, such as Ebola. But, surprisingly, it is the viruses themselves that hold some of the answers for speeding up vaccine production.
Viruses are icky. When a friend says, “I got a virus,” most of us take a step back, and for good reason. If you saw in detail how viruses work, you’d be more than creeped out. Ever seen a picture of a standard bacteria-targeting virus, like a bacteriophage? When these nasty critters land on a poor, unsuspecting bacterium, they insert their own genetic information into the host. The viral genes hijack the bacterial cell, take control of the cellular machinery, and use it to create more copies of the virus. And when the cell is finally filled to the brim with viral clones, the cell ruptures, spilling out hundreds of identical viruses into the world. And you thought your roommate’s mooching was bad.
In other words, a virus functions by inserting its own genes into a host genome, and then host proteins turn those viral genes into viral proteins and ultimately more viruses. The in-house enzymes can’t differentiate between viral and host genes. Moreover, the genes of viruses, bacteria, and humans are all decoded using the same universal language. This means that viruses could be engineered to deliver “good” instead of “bad” genes. For instance, viruses could be used as vectors for making and delivering antibodies to combat disease, which is exactly what scientists have in mind.
On paper, viral delivery vaccination systems and other types of genetically engineered vaccines are an upgrade to traditional egg-based vaccines. They’re fast to make — weeks not months. They’re efficient, partly because much of the vaccine genetic sequence analysis and engineering can be performed on computers using bioinformatics. And they require no eggs to incubate, no technicians to keep watch. In fact, the process is catered to automation and mass-production. Consider this: the annual flu vaccine begins production in February, well before the sniffles and coughs arrive. Specialists then get together to predict the three most common variants of the flu for next year. It’s really a whole lot of guesswork and, as such, their predictions can be hit or miss. But imagine if you could deliver an effective flu vaccine a mere week after the season begins! The effectiveness of flu vaccines would skyrocket.
Of course, there are downsides. Most importantly, control: how do we make sure that the “hijacked” cells don’t just keep pumping out antibodies? Science is still working on a functional off-switch for these other kinds of recombinant vaccines, but they’ve got an idea. Specialized vaccines provide immunity for a certain period of time before a booster shot must be reapplied. No booster, no immunity, no problem.
How far off are these vaccines? They’re already here. The Centre for Disease Prevention and Control (CDC) began research in 2013, and currently theirs is a seasonal flu vaccine that takes advantage of these kinds of methods. Vaccine approval processes take a long time, and the FDA is a mess of bureaucracy and red tape. But with the emergence of Ebola, the CDC may finally have the public support necessary to push through these developments. Many have hailed so called “viral vaccines” as the next big step in disease prevention. If anything, it shows that science is always ready to learn and find inspiration from nature.
This article originally appeared in Technophilic Magazine, and was written by Dennis He, a fourth-year science undergraduate student at the University of Western Ontario.
