Yes, they were all vaccinated. Every producer in Montana vaccinates against brucellosis.
As to what APHIS has done, I would ask them for some explanation, as to my knowledge they've done nothing other than issuing recommendations on further spacial separation, kind of what this elk occupancy agreement does (with no funding by APHIS).
They've not changed the rules related to quarantines on producers with enough positives within a certain period of time. They've not changed the rules related to a state losing its brucellosis-free status and huge consequences that come to all producers in a state where such happens.
I'm not sure if APHIS is handling CWD.
I'll give my brief summary on how illogical the APHIS rules are.
Producer level - If you get enough positives in your herd, you get placed under quarantine. You cannot sell any animals from your herd for at least 12 months, assuming you can avoid any further positives. Note, every positive in the GYE has been traced to elk, not bison. So, a producer who has a tolerance for elk ends up being at higher risk for positives. The financial hit is extreme. To carry your herd for a year, with feed, vet, and other costs is in the hundreds of thousands of dollars. You can't liquidate your herd, which you probably don't want to do given you many generations you've spent building that bloodline. You have to carry those costs and try to find a way to pay for your own living expenses with no money. By law, you are not allowed to sell any animals. All of this falls on your shoulders because you try to make some accommodations for elk. The rancher who grazes the hell out of his place and hazes elk continually has almost zero risk elk will want to be there, thus creating almost no risk.
Point being, given how financial punitive this positive designation can be, there is every incentive for producers to want no elk and almost zero incentive for producers to tolerate elk.
State level - As explained in the link from
@neffa3 above, a state can lose its brucellosis-free status if enough producers within that state go under quarantine. That's so friggin stupid. Why should a producer in Scobey lose their brucellosis-free state status when they are 350 miles from a problem in the Paradise Valley of Montana. There are WY/ID operations closer to the point of infection than many of the MT operators. For MT, WY, or ID to lose its brucellosis-free status would be a death nell for the working ranches in those states. These state wide threats are why Montana has declared war on free range bison, even though we've never had a known transmission from bison.
All of this comes to politics. The feedlot states benefit from the dark cloud that hangs over these Montana producers. They pay lower prices under the premise that they are taking on some disease risk. Yet, I've never seen a package of meat priced lower because it came from the brucellosis DSA (designated surveillance area).
You could get complete bipartisan vote in MT, ID, and WY for changes in APHIS rules related to financial penalties to producers. Likewise, you would likely get complete bipartisan opposition in the feedlot states where their constituents benefit from buying "disease risk" cattle and selling at full market prices.
Summary is this. We have brucellosis in elk at a very high prevalence in the Greater Yellowstone Region. Those elk benefit a ton of people and are the foundation of the entire wild food cycle. Billions are being made from tourism, millions from ranching and hunting, yet we have some crazy rules that result in incentives for fewer elk among the people who own the land where those elk live.
If a $0.25 fee was changed for every YNP vehicle, it would more than cover any damage losses caused by elk infecting cattle. And it would allow for huge amounts to provide incentive for more elk among those who have a personally high elk tolerance, yet cannot afford the financial costs of having more elk.
Hope that gives some insight. This is one of those places where hunters could be on the side of ag producers to the benefit of all; the producer, the hunter, and most importantly, the elk.