vaccine

[Melanie Courtot]

Hi all,

I would like to mireot the vaccine term from VO into OBI, under
MaterialEntity.

Definition is: vaccine is a processed material entity that establishes
or improves immunity in a host (e.g., human) to a particular disease.
Most vaccines are developed to protect against infectious pathogens.
Other vaccines are also developed, such as cancer vaccines and
autoimmune disease vaccines.

Let me know if you have any objection, otherwise I'll update the file
on Thursday.

Thanks,
Melanie