Scientists have been working on cold viruses for over 70 years,

but they've never found an effective cure.

The cold is the world's most prevalent infectious disease,

adults get between two and four colds a year and children get

way, way more.

So this means that you'll probably get over 200 colds in your lifetime.

And at any one point, hundreds of millions of people around the world

have a cold.

So we're going to talk about why it's so difficult to cure the cold

in a moment. But before that, we should go back to

the very first time we thought we were going to cure it.

The golden age of cold research starts in 1957,

with a scientist named Winston Price at Johns Hopkins University.

Price is the first person to ever isolate a cold virus in a laboratory,

and this is a really big deal because while people had described

the symptoms of a cold for thousands of years, nobody had ever found

the agent that causes it.

So Price becomes sort of like a minor scientific celebrity.

And he then announces that he's going to create a vaccine for it.

But, the vaccine doesn't work very well, it only protects against

a very, very small proportion of infections and Price has no idea why.

Now this is pretty disappointing, but it's good to think about

what's going on in science at the time.

People are incredibly, incredibly optimistic about the potential for

research and especially medical research.

The polio vaccine had just been created in 1955,

and it's the dawn of the age of antibiotics.

And after the Second World War, governments are really, really,

keen to invest in ambitious projects with definite goals

that solve big problems in society.

And so the cold becomes one of these things,

and a huge amount of funding comes down on the problem.

It moves beyond Price's lab and cold research centres open

across the entire world.

And my favourite one of these is the Common Cold Research Unit

in Salisbury, in England.

So the scientists there put ads in the local paper,

basically advertising a two week vacation in the countryside -

as long as you were willing to be locked in a drafty corridor or

to huff bags of cold infected air and let scientists observe you

for a couple hours every day.

And so what scientists unpick over the next 30 years from all of this,

is that the cold isn't caused by one virus, it's caused by seven different

viral families, and each one has subtypes which are called "serotypes"

which are recognised differently by the immune system.

And so, this is why the cold is so difficult to cure

and it's why Price's vaccine never worked, it was only for the one

cold family and one serotype he'd isolated.

The problem is, at the time that this is all known in the 1980s,

vaccine technology could only fit in a few serotypes per injection,

without causing an enormous immune response.

And so, you basically have the science that we know at an impasse

with the technology at the time.

And people have been working on colds for almost a generation,

25 or 30 years, and the scientific imagination has a tendency to wander.

Elite virologists and government funding

start moving more into other projects,

like AIDS - which is incredibly deadly

and almost a total mystery at the time.

And so colds kind of go out of favour as a topic of research

and the common cold unit even shutters in 1990.

Since then, we've gotten way better at dealing with infectious diseases.

We've eradicated smallpox, gotten measles, mumps, rubella,

tetanus, whooping cough, all kinds of things under control.

And so cold research has undergone a bit of a renaissance lately.

There's two totally different approaches that are both

quite promising.

In the UK, there's a group that's taking a look at every single

cold serotype, and trying to find a piece in common that they can target

a vaccine to.

It's quite like an elegant, direct approach.

And then there's an American company who's trying to create

a super vaccine.

So this would be one shot, with all 50 of the most common cold

serotypes in it. It's sort of a brute force approach.

But, despite the promise of all this research, there's still one big

hurdle to getting it finished and that has more to do with the

business of science than science itself.

The thing is,

vaccines aren't very good bets for pharmaceutical companies.

They're incredibly expensive to develop

and failure rates are really high, even late in trials.

It takes about $1 billion American dollars and almost a decade

to develop a successful vaccine.

Of all the thousands of pharmaceutical companies that

there are, only about five work on vaccines really seriously

and these are the biggest and richest companies.

And when it comes down to it, would you really get an expensive injection

just to avoid a few days discomfort? I probably wouldn't.

So, even after all the progress over the past 70 years

we'll probably continue to suffer from colds.

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