Is is possible to not abbreviate the author name of only one reference in my bibliography?

Your problem is not caused by IEEEabrv.bib, which simply contains the abbreviated names of IEEE journals; it is rather caused by the style IEEEtran.bst, which is programmed to abbreviate author names.

According to this, maybe you could write your author as

author = {{\relax World Health Organization} and others}

The \relax solution didn't work for me, but putting the author in double brackets like this got rid of the problem:

author = {{The Agda Team}}