Vaccines often cause a minor cosmetic bump. If you see people with a triangle of bumps on their shoulder for example they have received a common vaccine for healthcare workers.

And the smallpox one can leave an even bigger scar. I suppose they don't want the liability for that which could impact the model's income

Tabloid glamour models obviously aren't excluded, the posters joke was a reference to this

> excluded groups on the trial (page 3,

Ahh ok! :D

Now that you mention it I had heard of the British Page 3 tradition but it didn't occur to me at the time.