Other ways to reduce the risk is to separate the vaccinations by two weeks and pre-treat. Talk to your vet about options, and have your vet talk to United Vaccine about what should be done in the event of a reaction. Intestinal blockages are also a problem. Ferrets in their explorations can swallow items that won't pass through their system. Don't wait to see if something will pass.
Ferrets are small animals and blockages are very dangerous.
Many items may not show up on X-ray too, so don't rely on that for a diagnosis. Things to watch for are dehydration and that it doesn't turn into pneumonia, which can quickly turn fatal. Insulinoma, resulting in low blood sugar is seen with frequency, and is treated with surgury, drugs or both. It is very important to treat insulinoma, seziures that result from the low blood sugar will cause brain damage, and eventually death. Adrenal disease is also frequently seen and is mainly treatable through surgical removal of the adrenal glands which are overproducing hormones.