She's nine weeks old now and had her vac shot at 6 weeks of age. So I don't think it was caused by the vaccination itself. I don't know when she was wormed and what product they used.
But I agree with you that nobody can be blamed for it. Freak accident despite all precautions.
Update from this morning is that she's very bouncy and being force fed now. Hopefully she can keep some food down soon.