At 0 , 1 , 6 , and 8 months , group 1 received a 1 mL intramuscular dose of mpHBV ( containing 40 g HBsAg ) as a single injection , while group 2 received a 1 mL intramuscular dose of a licensed hepatitis B vaccine as two injections ( each containing 20 g HBsAg ; 40 g HBsAg total ) .