Comparing live attenuated and inactivated hepatitis A vaccines: an immunogenicity study after one single dose

While three types of hepatitis A vaccines are available in China, little data are available to compare them in terms of early antibody response. We conducted a trial to compare antibody response at 7, 14 and 28 days.

We randomized primary school children in Gansu and Jilin provinces into four groups to receive either (1) Chinese live attenuated hepatitis A vaccine (H2 strain), (2) domestic inactivated hepatitis A vaccine (Healive(®)), (3) imported inactivated hepatitis A vaccine (Havrix(®)) or (4) hepatitis B vaccine (Control group). We compared groups at 7, 14 and 28 days in terms of proportion of sero-conversions (≥10 mUI/ml), and Geometric Mean Concentration (GMC) of antibodies measured with a Microparticle Enzyme Immunoassay (MEIA). We compared rates of self-reported adverse events following immunization (AEFI) in the first three days.

204 children received the H2 vaccine, 208 received Healive(®), 214 received Havrix(®), and 215 received hepatitis B vaccine (no differences across groups in terms of age, sex, weight and height). At seven days, sero-conversion proportions were 25%, 35%, 27% and 2% (p<0.0001) with GMC of 6 mIU/ml, 8 mIU/ml, 6 mIU/ml and 3 mIU/ml, respectively for the four groups. At 28 days, sero-conversion proportions were 98%, 100%, 93% and 3% (p<0.0001) with GMC of 47 mIU/ml, 71 mIU/ml, 67 mIU/ml and 3 mIU/ml, respectively. AEFI were benign and did not differ across groups (p=0.94).

While our study was not able to identify differences between Havrix(®), Healive(®) and H2 vaccine in terms of sero-conversion proportion and GMC between seven and 28 days, further studies should evaluate non-inferiority or equivalence of the Chinese vaccines, particularly with respect to the GMC concentration for the H2 vaccine since it could affect long-term protection.