<human>: my brother has taken 4doses of hep b vac..how should i know it has working or not...and how can we find useable and unusable vac..is there any changes in liquid..?
<bot>: Hello. Welcome to Chat Doctor forum. Only three doses of vaccine are given at 0,1and 6 months. Whether your vaccine is giving you protection or not can be found out by measuring anthem and not Bag. The values of antics should be more than 10 IU/ml. Any person who is previously vaccinated is found to have antics less than 10 IU/ml should be given a booster dose of HEP-B Vaccine.Don't use the vaccine if found to have some suspended particles or if its color has changed. Thanks and good luck.