Roderick Murray made a significant rejoinder, as I recall. He said that we do not approve the substrate on which a vaccine is produced, we only approve or disapprove of the vaccine after it's made, which gave him considerable wiggle room to deny any responsibility for a five or seven year delay, in which several people died, because of… In manufacturing facilities, I should say, not vacinees, where primary monkey kidney was used.

As a result of that, and Frank Perkins' absolute agreement with my belief, and that of Drago Ikić, that these cells should be used for vaccine production, was an important personality also in promoting this idea. Frank gave several papers advocating this in the UK, at World Health Organisation meetings. I remember one distinctly, in France in… at a rabies meeting, but there are many examples of his… his advocacy that could be made. In the early '70s I learned that Pfizer laboratories, in Sandwich, Kent, was planning to make a poliovirus vaccine.

This was, I believe, one of the first vaccines that was destined ultimately to be used in the United States, or at least to be submitted for licence in the United States. The Pfizer company asked me to help them in some of the manufacturing technicalities, which I did do on several occasions, when they invited me to Sandwich to give a couple of lectures and look at some of the technical problems. So that in approximately 1972, I think it was, the first vaccine produced in the UK against polio in WI-38 was... was available for public use, and about the same time, or a year or so later it became available in the United States.