INTRAMUSCULAR VERSUS INTRADERMAL HEPATITIS B REVACCINATION IN HEALTHY NON-RESPONDER CHILDREN： A 5-YEAR PROSPECTIVE RANDOMIZED STUDY

Objective: With the same times of injection to compare low-dose intradermal regimen with routine-dose intramuscular inoculation in revaccination of non-responders to hepatitis B vaccine. Methods: 40 healthy non-responder children collected by screening were administrated a three-dose revaccination randomly by intramuscular or intradermal route (10 vs 2 g per dose), and regularly tested for serologic markers up to five years. By the end of follow-up, a booster dose (5 μg) was given to those who had lost anti-HBs of ≥10 mIU/mL (seroprotection) and anamnestic response was estimated thereafter. Results: All 17 intramuscular and 22 of 23 intradermal children effected seroprotection after revaccination. Intradermal children lost seroprotection over time significantly rapider compared with intramuscular children (Log Rank test, P = 0. 029). In year 5, 50% of intramuscular but only 18.2% of intradermal children still maintained seroprotection (P = 0.075). 12-14 days after the booster dose, all the eight intramuscular children developed an anamnestic response with anti-HBs titer increasing greater, but two of the 18 intradermal children failed to mount seroprotective level. Conclusion: Three-routine-dose intramuscular revaccination was significantly effective than low-dose intradermal one with the same times of injection, especially in long-term immunity. We recommend routine-dose intramuscular protocol in revaccination of non-responders.