Vaccines are generally very safe, and most side effects (like mild pain or fever) resolve on their own. However we ask all patients to wait for 30 minutes as a standard safety precaution. In extremely rare cases, a person may experience an immediate allergic reaction (anaphylaxis). This reaction might include symptoms such as hives, fainting, difficulty breathing, or swelling of the face/throat. While extremely uncommon (occurring in fewer than 1 in 1 million doses), it requires urgent medical attention. By staying in the clinic, you ensure that our medical team is right there to provide immediate and effective treatment if you feel unwell. Once treated, patients recover fully and quickly.