BEAT-BK will see the effect of immunosuppression reduction/modification with and without IVIG on BKPyV infection, allograft function, allograft loss, acute transplant rejection, immunosuppression load and death in kidney and simultaneous kidney pancreas transplant recipients with polyomavirus infections (BKPyV).
Inclusion Criteria: 1. Aged 2 years or above 2. Have received a kidney or simultaneous pancreas-kidney transplant 3. Have BKPyV-Viremia (detected by RT-PCR) with a viral count ≥ 5,000 copies per mL, or histological confirmation of BKPyVAN, within 3 weeks prior to randomisation. 4. Be able to provide informed consent or consent given by a parent or guardian (if age \<18 years) or other authorised person Exclusion Criteria: 1. Contraindications to receiving IVIG as a treatment 2. Current active acute rejection (≤ 3 months prior) 3. Treating clinicians would regard as unsafe to be enrolled 4. Limited life expectancy (\< 12 months) 5. Receiving Belatacept as part of their immunosuppression protocol 6. Currently undergoing or who have previously received, viral-specific T-cell therapy for BK viremia 7. Prior infection and treatment for BKPyV-Viremia 8. Received IVIG treatment in the past with last IVIG treatment \< 4 weeks prior to randomisation