Could a polio vaccine help us fight COVID-19? When I first heard that idea I
thought there's no way, polio has nothing to do with coronaviruses. Turns out it's
not as crazy an idea as I first thought. I called up one of the researchers who's
proposing it, Dr. Robert Gallo. Dr. Gallo was one of the co-discoverers of HIV and
he is a huge name in biomedical research.
[DR. GALLO] This has a chance. A moment like this is
for a decisive action and we think it has a real chance of stopping the epidemic.
[SAM] So how could a vaccine for polio keep you from contracting a
totally unrelated disease? Generally speaking, it comes down to what the oral
polio vaccine does to your immune system. More specifically, how it interacts with
your innate immune system, versus your adaptive immune system.
[DR. OZOG] Think of your favorite spy movie, you know like when the spy is invading the
compound, like James Bond's trying to get in to sneak into the the base of the bad
guy the innate immune system is kind of more like the guard dog that's you know
walking around. It's, it's not specifically looking for a James Bond
but it knows that anybody who comes over the wall wearing a ski mask it needs to get bit.
[SAM] Your innate immune system is the guard dog. It's not looking for anything
specific it just attacks anything that looks dangerous.
[DR. OZOG] I would say the adaptive response is more like a Special Forces sniper. It has the picture
of James Bond it, knows what James Bond looks like, and it knows exactly who they're targeting.
[SAM] When you give someone any form of a vaccine you're training
the sniper. You're giving your adaptive immune system a picture of the virus and
saying, next time you see this kill it. The oral polio vaccine doesn't just
train the sniper. It also startles the guard dog.
That's because it's what's called a live, attenuated vaccine. A live, attenuated
vaccine contains a complete virus or bacteria that's been weakened in the lab.
It wakes up the guard dog and that guard dog
is angry. Or, to use actual scientific terms here,
it activates your innate immune response. Unlike the oral polio vaccine the polio
vaccine you have injected is not live and attenuated, it's what's called an
inactivated vaccine. Inactivated vaccines don't use
complete live virus and bacteria. They're made using a physical process like heat,
or chemicals like formaldehyde to inactivate little pieces of bacteria or
viruses. Those pieces, great at building adaptive immunity, but they don't really
spook the guard dog. So the idea here is that the oral polio vaccine would amp up
your innate immune response which would release that guard dog on SARS-CoV-2.
Now you might be wondering why your innate immune system isn't just doing
that on its own. Why would it need help from a live attenuated vaccine to stop
COVID? So it turns out that SARS-CoV-2 can make your innate immune system act
kind of erratically and even block it from responding. That causes lung
inflammation and fluid buildup that you would see in severe COVID cases. Taking
the oral polio vaccine might help keep that from happening.
[DR. OZOG] You could fight off the virus early before it really establishes a good
infection, and then later on hopefully that's enough to prevent this
inflammatory lung destruction that happens in the in the later process
of SARS-CoV-2 infection. [SAM] So the big question is will the live attenuated
oral polio vaccine wake up your innate immune system's guard dog enough to
prevent you from getting COVID-19?
[DR. GALLO] This has a chance, if it works. Am I a hundred
percent sure? No, I'm a hundred percent sure of almost nothing, so you know, not
a hundred percent sure, but we think it has a real chance of stopping the epidemic.
[DR. NIZET] So I think we're looking at interventions that might buy us a little bit of time
before a bonafide SARS-CoV-2 vaccine emerges in 2021, hopefully.
[SAM] I also want to mention that the oral polio vaccine is not the only live, attenuated
vaccine that's being considered. Vaccines for tuberculosis and measles are also in
the mix, and the idea is that they would also boost your innate immune response.
Even in the best case scenario these options are really only going to protect
you in the short term, so maybe for a few months at a time. That
means that you would have to take them every few months until there's a vaccine
for SARS-CoV-2 available.
[DR. GALLO] And when you develop a very good coronavirus vaccine,
which is specific, which is long lasting, that would be great. But the truth of the
matter is, it's certainly not in time for this epidemic, and further truth
of the matter is you never can give a date for a vaccine. I mean, I hear a lot
of suggestions for about the months will take to get it, but reality is, you have a
vaccine when you have a vaccine.
[SAM] So at the end of the day these are really just
buying as time. You can buy us even more time by staying home, washing your hands,
avoiding large gatherings, keeping your distance from other people, and wearing a
mask. Maybe just sit on your couch and binge your favorite American Chemical
Society YouTube series. Stay safe, everyone.