Immunogenicity of double doses of hepatitis B vaccine in cirrhotic patients in waiting list for orthotopic liver transplantation: a randomized clinical trial / Imunogenicidade de doses dobradas da vacina contra o vírus da hepatite B em pacientes cirróticos em lista de espera para transplante de fígado: estudo clínico randomizado

Patricia Rodrigues Bonazzi

BACKGROUND: Vaccine against hepatitis B is recommended for all cirrhotic patients, by another etiology, in waiting list for liver transplantation. However the vaccine response described in this population is lower than in immunocompetent adults. Strategies to increase its immunogenicity are discussed in the literature, as the application of double doses, usually recommended in immunocompromised populations. This study compared response to the vaccine against hepatitis B virus in a single dose regimen with a double dose regimen, and evaluated the influence of other features associated with vaccine response in cirrhotic on the waiting list for liver transplantation. METHOD: A prospective and randomized clinical trial was conducted between October 2006 and September 2008. Adopting confidence interval of 95% and a power of 80%, calculated sample comprised 103 patients in each group. Considering an estimated mortality of 10%, final calculated sample resulted in 113 patients to receive the scheme 0, 1, 2 and 6 months with a single dose, and 113 to receive a similar scheme with double doses. Vaccines used were Euvax and Butang. Vaccine immunogenicity was assessed measuring anti-HBs after the third and fourth dose of vaccine. RESULT: We selected 738 patients in waiting list for liver transplantation and included 232. There was no statistically significant difference between the groups that received single or double doses in the analysis of vaccine response after the third dose (35.2% vs. 37.2%, p = 0,8). Overall seroconversion after the fourth dose was 66.9% (85/127). There was no difference between the groups with double and single dose after the fourth dose (64.5% vs. 69.2%, p = 0,57), but analysis adjusted for some confounding factors such as age , BMI, MELD and blood group, found odds of seroconversion among patients who received double doses 2.57 times that of patients who received single doses. This difference was statistically significant, but confidence interval included 1 (OR = 2.57, 95% CI = 1 to 6.63, p = 0.043). Features as age, BMI and blood group were predictors of vaccine response after the fourth dose of vaccine. CONCLUSION: There was no difference in vaccine response between single and double doses in cirrhotic patients after the proposed scheme. The poor response after accelerated schedule (0.1 and 2 months) does not contribute to adopting this scheme in clinical practice. Number of doses and interval between them may be more important to vaccine response than single or double doses.

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