Seroprotection after Hepatitis B Vaccination in Expanded Programme on Immunisation

Aim: As part of a global strategy, Pakistan included the Hepatitis B (HB) vaccine in the national Expanded Programme on Immunisation (EPI) in 2004. The aim of this study was to know the status of seroprotection amongst those receiving HB vaccination in the EPI in Pakistan. Introduction: Hepatitis B vaccination has produced very convincing results in reducing disease burden in the developed world. As per the World Health Organisation (WHO) recommendations, most countries have included HB vaccination in the national EPI schedules. Pakistan included the HB vaccination in the EPI in 2004. There are various factors affecting seroprotection after HB vaccination done in the EPI, for example dosing schedule, maintenance of the cold chain and missing the birth dose, etc. There are no published studies to date regarding seroprotection status and anti-HBs antibodies levels after receiving the HB vaccination in the EPI in Pakistan. Methods: This study was conducted at the paediatric departments of Military Hospital (MH) and Combined Military Hospital (CMH), Rawalpindi from 1st January 2010 to 31st December 2010. One hundred and ninety-four children ranging from 9 months to 2 years of age, who had received HB vaccination according to the EPI schedule, were included. Blood samples were taken and tested for anti-HBs antibody levels by enzyme-linked immunosorbent assay (ELISA) at the Department of Biochemistry of Army Medical College, Rawalpindi. Anti-HBs antibody titres >10 IU/L was taken as seroprotection level as per WHO and kit manufacturers' standards. Results: Out of 194 children, 133 (68.6%) had anti-HBs titres > 10 IU/L (seroprotected) while 61 (31.4%) had anti-HBs titres 10 IU/L (protected) and 61 (23.2%) had anti-HBs titres 10 IU/L (protected). The difference was significant between the public sector procured and privately procured vaccine (p-value= 0.028). One hundred and thirty-two children received the HB vaccination at army vaccination centres (MH & CMH). Out of them 96 (72.7%) developed anti- HBs levels >10 IU/L (protected) and 36 (27.3%) had antibody titres 10 IU/L (protected) while 27 (41.5%) had antibody titres <10 IU/L (non protected). Conclusion: Seroprotection achieved after HB vaccination received in the EPI at 6, 10 and 14 weeks in combination vaccination form was 68.6%. This is low as compared to results reported internationally. Geometric mean titre (GMT) levels achieved in seroprotected vaccine recipients are also low (85.81 IU/L) when compared with international data. There is a need to look into relevant aspects of HB vaccination in the EPI to improve seroprotection in