Immunoglobulins for preventing hepatitis A.

BACKGROUND: Hepatitis A (infectious hepatitis) is a common epidemic disease. Immunoglobulins for passive immunisation are used as prevention.

OBJECTIVES: To assess the beneficial and harmful effects of the pre- and post-exposure prophylaxis with immunoglobulins for preventing hepatitis A.

SEARCH STRATEGY: We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, The Chinese Biomedical Database, and Science Citation Index Expanded for trials until October 2008. In addition, we read through reference lists of the identified publications and handsearched three journals.

SELECTION CRITERIA: Randomised clinical trials on immunoglobulin prophylaxis for preventing hepatitis A, irrespective of blinding, publication status, or language.

DATA COLLECTION AND ANALYSIS: Data were extracted by two authors and verified by a third author. Results were presented as relative risks (RR) with 95% confidence intervals (CI). The primary outcome was occurrence of hepatitis A (infectious hepatitis).

MAIN RESULTS: We included 13 trials with 567,476 participants randomised to pre- or post-exposure prophylaxis. The trials had high risk of bias. The trials were heterogeneous in terms of study setting, participants, interventions, and outcome measures. Our meta-analysis with six randomised trials showed that immunoglobulins, when used for pre-exposure prophylaxis, significantly reduced the number of adult patients with hepatitis A at 6 to 12 months (1020/286503 versus 761/134529; RR 0.53; 95% CI 0.40 to 0.70; random-effects model) in comparison with no intervention or inactive control. Four trials showed a similar effect in children aged 3 to 17 at 6 to 12 months follow-up (917/210822 versus 677/78960; RR 0.45; 95% CI 0.34 to 0.59). Comparing different doses of immunoglobulins, higher dosage was generally more effective than lower dosage (1.5 ml better than 0.75 ml and 0.75 ml better than 0.1 ml) in preventing hepatitis A. No significant systemic adverse events were reported. One trial showed that immunoglobulin was more effective than placebo for post-exposure prophylaxis. It appeared that there was no significant difference between immunoglobulins and inactivated hepatitis A vaccine in seroconversion to hepatitis A vaccine antibodies at four weeks (RR 1.16; 95% CI 0.98 to 1.38), but immunoglobulins were significantly less effective than vaccine regarding antibody levels at 8, 12, or 24 weeks.

AUTHORS' CONCLUSIONS: Immunoglobulins seem to be effective for pre-exposure and post-exposure prophylaxis of hepatitis A. However, caution is warranted for the positive findings due to the limited number of trials, year of conductance, and risk of bias. Conductance of rigorous trials will be justifiable.