That's an interesting question.
On the one hand, yes, the WTS says in every one of its missives regarding the vaccines, "medical treatments are a matter for personal decision, we do not make rules for others".
On the other hand, The WTS views its Bethel workers as a sort of "family", and the bosses (GB, branch committee members) are the "family heads". And in WT-world, "family heads" have the authority to set "family rules".
As an example, in the US Bethel, it is absolutely forbidden to watch "R-rated" (age 17+) movies, a restriction that is not written out explicitly for non-Bethelites (a non-Bethelite might get "strong counsel" from the local elders, but that's really different).
Breaking a "Bethel family rule" is grounds for dismissal.
In WT-world, a "family head" can make medical decisions for his family.
So....on the one hand, the sooner a sort of "herd immunity" is reached, the sooner things get back to "normal". Vaccines are the quickest, safest way to "herd immunity". On the other hand, it's a broad ethical issue - can employers require their employees to receive the vaccine? It is an open question, there will probably be lawsuits in the future regarding this.
I have no idea what the WTS will do.