Conjugate and 23-valent pneumococcal polysaccharide booster vaccination in asplenic patients with thalassemia major: A randomized clinical trial study

Background: Pneumococcal vaccine provides protection against invasive pneumococcal disease in population at risk. This study was conducted to compare the antibody response to 13-valent pneumococcal conjugate vaccine and 23-valent pneumococcal polysaccharide vaccine in patients with thalassemia major. Methods: A randomized cross-over clinical trial was performed on 50 asplenic patients with thalassemia major who referred to thalassemia center at Bouali Sina Hospital, Sari, Iran from 2013 to 2014. Patients were divided into two equal groups. The first group received 13-valent pneumococcal conjugate vaccine (PCV) injected into the deltoid muscle at first and received 23-valent polysaccharide vaccine (PPV) by the same way two months later. The second group received PPV vaccine at first and PCV13 two months later. Levels of serum antibody were checked and measured by enzyme-linked immunosorbent assay (ELISA) before vaccination, and then 8 weeks after the first injection and 2 months after the second injection in all patients. Each time 0.5-ml dose of the vaccine was injected. Results: Of the 50 patients, three cases were excluded due to lack of cooperation and avoidance of vaccination.  From 47 patient participants, 28 (59.6%) were males and 19 (40.4%) were females with age ranged between 20 to 44 years (average age of 29.6±1.4 years). Pneumococcal IgG levels in a group that used PCV before PPV (Group A) increased from 114.5±87.7 to 1049±720 U/ml (p=0.0001) and in another group that used PPV before PCV (Group B) increased from 115±182.2 to 1497.3±920.3 U/ml (P=0.0001). Conclusion: It can be concluded that PCV vaccine before PPV can be more effective in asplenic thalassemia major patients as a booster dose.