[syhprum (OP)]

Presumably regular grocers eggs are not suitable do the eggs have to come from certified virus free stocks and do they have to be fertile, what do they cost and how many are required to make the seasonal Flu vaccine for the UK ?

[evan_au]

They would need to be free of salmonella.

Salmonella is endemic in commercial chicken farms - fortunately, most of us cook our eggs before eating...