It is usually possible to get the hepatitis B vaccine when you have your period, but it is recommended to avoid the menstrual period. Hepatitis B vaccination requires no allergy to proteins, and is not recommended for patients with fever, acute illness, or acute exacerbation of a chronic disease, which may lead to worsening of an adverse reaction or aggravation of the disease and affect the vaccine’s efficacy; however, menstruation usually does not affect the vaccination and efficacy of the Hepatitis B vaccine. Therefore, it is usually okay to get the hepatitis B vaccine when you have your period. Some people may have an adverse reaction to the hepatitis B vaccine. Menstruation itself can be uncomfortable and may increase the likelihood of an adverse reaction to the vaccination. It is recommended to avoid the menstrual period and wait until the period is over before getting the Hepatitis B vaccine. If you need to take the Hepatitis B vaccine during menstruation, you can consult a professional doctor for specific advice to avoid discomfort.