Which of the following is NOT a proper practice when preparing a vaccine?

When preparing a vaccine, proper practices are critical to ensure patient safety and the effectiveness of the immunization process. One key aspect of vaccine preparation is maintaining sterility and minimizing contamination during the procedure.

Removing the vaccine cap using hands is not a proper practice because this can introduce contaminants from the skin to the vial. Hands carry bacteria and other pathogens, and touching the cap can compromise the sterility of the vaccine. In contrast, the other options represent proper practices: checking the expiration date ensures that the vaccine is still effective, using an alcohol pad to swab the vial helps to disinfect the rubber stopper and reduce the risk of injecting any bacteria, and making sure the syringe is free of air bubbles is essential for accurate dosing and to prevent complications during administration. Each of these practices contributes to a safe and effective vaccination process.