It's safe to say that vaccines have come a long way. Gone are the days of scraping some
pus from a cow and giving it to your wife and sons. Sure it was worth it to prevent
smallpox, but still...
After the last year we've seen just how progressive we can be at developing a vaccine. Never before have we
made one so efficiently, but COVID has done more than
just spark the development of COVID-specific vaccines, it has actually helped advance the
entire industry in an unprecedented way.
Vaccinology has been a Field of Dreams that's been replete with innovation for the last
225 years. And I think the COVID 19 pandemic that started more than a year ago has brought
this to the fore. My name is Bali Pulendran, I am a professor of pathology and microbiology
and immunology.
When it comes to the future of vaccines, there are a lot of avenues that are making strides
with things like mRNA vaccines, delivery systems, epigenetics, and universal vaccines... and spoiler
alert, we're getting a lot closer to a certain type of universal vaccine than you may think.
Vaccinology is a discipline that is positioned at the focal point of immunology, virology
microbiology, public health, economics, sociology, ethics, and even international diplomacy.
So when one thinks about the future of vaccines, one has to think about each of these elements,
the future of each of these elements.
One of the most exciting developments for the invention and distribution of vaccines
is mRNA.
mRNA vaccines is of course the new kid on the block, they've been extraordinarily efficacious
in protecting against COVID-19. And the thing that everyone says is that these vaccines
were developed in such a short time, in a period of 11 months or so. But the important point
to remember is that it's not as if we didn't know about the mRNA vaccines prior to the
emergence of COVID-19, there were teams of scientists working on this concept for years.
It just so happened that when COVID-19 emerged, they were rapidly able to pivot and to use
that technology, that investment that they had made over the last decade.
mRNA or messenger RNA vaccines are such game changers because of how they're made, a traditional
viral vaccine will deliver an inactivated, weakened or small piece of a virus to stimulate
an immune response. But the neat thing about mRNA vaccines, is that they deliver the genetic
instructions directly to your cells, telling them exactly how to make the specific protein
needed to generate that immune response. It's tapping into the way that mRNA typically helps
cells to build, maintain and repair things in our bodies using proteins.
Now why this is so unique is that if you didn't have this mRNA technology, you would not have
access to our own cellular factories the so called ribosomes, we would be so dependent
on manmade factories to produce these proteins and protein production is a whole new step
and that can take a very long time several months perhaps a year or longer. So effectively
what we've done is to bypass that entire protein production and use our body's own factories
to our benefit.
Right so mRNA means that you don't have to wait for all those proteins to be made, you
can just teach cells, how to make it on their own. It's a teach a man to fish kind of thing,
or like a teach a ribosome to mass produce a spike protein kind of thing. But even mRNA
vaccines are limited in that they teach the immune system to respond specifically to one
virus. So what if our vaccines didn't have to be so specialized per virus, or in the
case of something like influenza, so specific to each variant of the virus, the development
of a vaccine is predicated on the concept of teaching the immune system to recognize
a very specific antigen, and priming cells that recognizes antigen in this case. Now,
this is the concept on which vaccines are made immunological memory so that when this
person encounters that particular pathogen decades afterwards, he or she has these memory
cells that recognize that pathogen and have the capacity to respond in a much more accelerated
manner and a much more invigorated or enhanced manner.
But if we could pull everything we know about influenza viruses or the different kinds of
coronaviruses and teach the immune system to look for more than just individual antigens,
then we would bypass the need for these hyper specific vaccines. This vaccine would teach
the immune system to respond to anything that looks like a flu virus, even if it hasn't
encountered its exact makeup before.
So I would say over the next five to 10 year frame and I think I'm being quite conservative.
I wouldn't be surprised if we have something that looked like a universal influenza vaccine
that's ready for deployment. That's great,
but let's zoom out even further. Are we at all close to a vaccine that would just fight
off anything? One shot to rule them all?
Within a few seconds of you getting your COVID vaccine shot your innate immune system is
activated, and it teaches the T cells and the B cells to launch a vaccine response.
Now, recent work over the last, I would say two or three years, suggests that the innate
immune system can have another role. It's not just a short-lived response that merely
teaches the T and B cells to do their job, but it can also have a response that lasts
a bit longer, not just a few days but perhaps a few weeks and maybe even a few months, and
that response can actually fight off infections.
And this is where it gets interesting. Instead of having to wait for your adaptive immune
system that's those T and B cells to learn how to find and fight or virus, triggering
what are called epigenetic changes in the cells of the innate response could simply
tell the immune system to kill a virus right away.
So if you could deliver an adjuvant that could cause epigenetic imprinting and a heightened
degree of resistance in the innate immune system for some period of time, perhaps, you
know, a few weeks or maybe a few months, that would provide an effective sort of stopgap
measure that would confer a degree of protection against any virus that could emerge, then
effectively you bridge that gap that critical window of time of a few months in which people
are now being exposed to this virus but we don't have conventional vaccines.
So in short, you'd be getting a vaccine that turbocharges the innate response via epigenetic
imprinting to blast any virus that comes along, but that could be enough for us to keep a
disease at bay while we develop long term adaptive vaccines, when we have a mysterious
new virus going around. But while we wait for these turbo vaccines, those of us with
trypanophobia, just want to know when we can get vaccines that don't require a needle,
Are we
always going to get an injection, or are there other types of vaccines? Well this is a question
my 11 year old daughter asks me constantly, there are efforts underway to mucosal
vaccines. These are vaccines that can be delivered orally, perhaps intranasally, and the great
advantage of mucosal vaccines, is that they could be administered, much more easily and these
issues come into play in the developing world.