Greetings, I want to ask, I have done the vaccine 3 times in 2017. I check this 2019, the anti-HBs level was detected 25.31 with a reactive reference value of u0026gt; = 1.0 negative u0026lt; 10 units of IU / LA. small? Do I have to be a booster? And what about the bosteer regulations? I have vaccinated 3 times but why doesn’t the result reach 100 huh? Is it because the type of vaccine used is not good?