Q: My 22 year old mare had strangles two and a half years ago. I am wondering if it is safe to vaccinate her for strangles now.
A: Since your mare had strangles relatively recently, I would recommend having her antibody levels tested to see if they are still high. If they are 1,600 or higher, vaccination is unnecessary and use of vaccine could trigger an episode of purpura hemorrhagica.
Without testing, there is no way for sure to say if vaccination will be safe. Your veterinarian will be able to evaluate the antibody levels with a single blood test.
By Christie Ward, DVM, PhD, University of Minnesota