THis does not meet current best practices. As we learned from this lesson, it can increase the risk of transmission for bacteria and blood-borne pathogens. The vials might be from different batches, and their contents might not be identical. They could have different expiry dates, which means one might not be as effective. Plus, there’s no way to be sure if they were stored or handled correctly, so it’s safer to stick to the standard dosing protocols to ensure you’re getting the full, safe dose. Mixing and matching just adds too much uncertainty and risk.