Professor Tim Spector

I mean, most of the stresses we get every day are not like our ancestors had.

We're not being chased by wild animals or being burnt out of our village, you know.

So the... And...

What really interested me was this whole link between what happens when you have a vaccination.

During Zoe, we looked at a million people's responses to the, if you remember, the Pfizer vaccine and the SK vaccine.

And what was really interesting was that people were actually depressed during that time.

So you had about 24 hours of depression, which was mimicking...

a more constant threat.

And this suddenly brought home this idea that you can trigger depression through a little shift in your immune system.

There's a really growing theory about people who have long-term depression is that their immune changes are switched on so that they're getting the equivalent of this constant tickling of the immune system by a vaccine.

So

That, to me, was a really important thing because I have vaccines.

I have regular vaccines.

I'm a big believer in vaccines.

But they do make you feel a little bit down.

That makes sense because your blood tests will show a spike in your proteins for inflammation.

Your immune system is kicking in.

That sends signals to your brain.

Your brain says, okay, it looks like I've got an illness coming here.

That illness behavior in some people then gets carried on.