In the field of cell and gene therapy, there are two main types of viral vectors: adeno associated virus (AAV) and Lentivirus (LV). The manufacture of these vectors is dependent on the regulatory requirements dictated by its end use. AAVs are most commonly used to deliver gene therapies – meaning they will be administered directly to a patient. In contrast, LV is typically used as an input material to genetically modify cells used for cell therapies (e.g. CAR-Ts) and is not included in the final product delivered to the patient.