Twelve studies were included (n=640), 11 of which were randomised controlled trials (RCTs).
The pooled OR of failure to respond to HBV at completion of vaccination against HBV was 0.36 (95% CI: 0.21, 0.62) using a fixed effects model, with no evidence of heterogeneity. Pooled OR of failure to respond to vaccination over follow-up was 1.1 (95% CI: 0.47, 2.5) using a random effects model, with weak evidence of heterogeneity (p=0.04). The mean estimate for peak anti-HBs antibody titres for ID compared with IM was 341 ± 226 versus 333 ± 259 mIU/L.
A significant association between seroprotection rate and number of vaccine shots was evident (p=0.002). No liver-related adverse-events were reported in the studies, with the rate of minor local/systemic reactions after ID vaccine varying between 0 to 100% and after IM vaccine between 0 to 36%. Liver related adverse-events were not recorded.
There was no evidence of publication bias.