let me explain to you.

Hepatitis B is sexually and blood transmission disease.
what's the problem with Hep B?
liver problem, this virus will cause liver damage, later liver cirrhosis, and some turn into liver cancer.
What's the problem when you have liver disease?
you'll become yellowish, you'll have abdominal pain, fluid start accumulate in your tummy, and it become bloated due to fluid shift into your tummy, and your immunity become very weak,
some develop things call portal hypertension where because of liver cirhosis, the circulation's pressure increase, this leads to other problem, such as oesophageal varices , where you can bleed from your esophagus, etc.

n conclusion, you wont die from the disease, but you die from the complication of liver failure, liver cirrhosis.

okie, back to the immiunization.
how can it protects you.
First, most 90% carrier in our population got it from their childhood, means from their close people, parents, or when they born...(if they are not immunized during birth)
the other 8% PROBABLY DUE TO SEXUALLY TRANSMITTED, and the rest probably due to other causes such as blood transfusion, sharing needle, etc.

If your parents are carrier, there's a chance that you might /might not get it, depends whether you're in the immunization program started in year 1985, if you're borned before that, then chances of you being Hep B carrier is higher if your parents are carrier. you should get yourself a check if you havent..

okie, next,
if you're not immunized with Hep B,
it's okie, because normal adults have adequate immunity to fight against Hep B virus, 1/10 normal adult (non immunized) will be infected with Hep B and become a carrier, while the rest 9/10 will free from the disease after infection, subsequent develop passive immunization after the infection.

Hep B Immunization.
the protection against Hep B infection depends on the immunization titre in your body. the higher antibody level in your blood, the lower risk you'll get.
generally, safe level >100 IU/L, minimum level 10IU/L
safe level protects up to 95%, while if between 10-100, u need a booster, and if less than 10IU, u need to take all 3 doses again.

in conclusion, Hep B is very prevalence in asian country...just becareful.