Hep B is a sexually transmitted and a blood borne pathogen of concern. To make this short and sweet, with a hx of being vaccinated you should obtain your hep B titers first to see if you have not lost your protection (about 30% of the population's hep B vaccine immunity diminishes with time), if not have fun in Korea. If titers are low or negligent, try to get at least 2 of the three shots prior to your trip. Good luck!

Hi,
People in a high risk group for Hep B virus should take the vaccine wherever they are .If you are in a high risk group such as health care professionals or with unprotected sexual contacts ,or with diseases that require Blood or its contents,..or with IV drug use(in addiction) &.. ,you have to pay much attension to this issue.If you have done your vaccination completely before,i recommend you to check your Ab titer (Anti Hep B Anti body :Anti HBV IgG Ab).It is a simple blood test that its titer shows your immunization against Hep B virus.If it is in a range of protection,you don't have to be worry about taking a new vaccine and if not you should visit your doctor for further works.

if you already had the complete series, then, you should not need to repeat it. You may however,want to check your titer to ensure you have active immunity. You should consult with the travel medicine devision managed by an infectious disease doctor...

For true immunity, you need to complete a SERIES of shots for Hep B. Start at least 6 months before your trip if possible.

It is true that the prevalence for HBV among Asian countries is higher, in general. However, if you have had the three (3) HBV series immunizations, you should be fine. If you have worries or doubts, you can have a titer completed. Depending on the results, a booster may be in order. You should have this test and booster completed at least 4 weeks before your trip.

No I believe that the original series offers a lifetime of protection unless there are mitigating circumstances, in which case public health would make it mandatory for US travelers.