Post-vaccine immunity against hepatitis B in Moroccan children

Abstract

Background: Hepatitis B is a major public health issue worldwide. Immunization of infants against this disease has been effective in Morocco since 1999. However, evaluation of post-vaccination response is rarely performed in our setting. The purpose of this study was to evaluate immunity against HBV in fully vaccinated children in the city of Marrakech in Morocco and to investigate the factors influencing the level of post-vaccination immunity. Methods: A descriptive cross-sectional study was conducted on fully vaccinated children who have medical and vaccination records, from three primary healthcare centers in Marrakech. Children with anti-HBs antibody levels between 10 and 100 IU/L were considered moderately immune, and those with antibody levels above 100 IU/L as highly immune, while those with antibody levels below 10 IU/L were considered non-immune. Results: Of the 123 children recruited, 114 (92.7%) had protective anti-HBs antibody titers, of which 37 (30%) were moderately immunized and 77 (62.7%) were highly immunized, and nine (7.3%) were non-immune. Age, birth weight, vaccine type, and time since the previous dose have all been significantly associated with the degree of post-vaccination immunity. Anti-HBs antibody levels were not significantly related to factors potentially linked to post-vaccination non-response, such as chronic disease, immunosuppressive medication and others. Conclusion: Our findings denote that the HBV vaccine used in The Moroccan Expanded Program on Immunization (EPI) is effective against HBV. Nevertheless, in non-responders, corrective actions such as re-vaccination and monitoring of post-vaccination anti-HBs antibody levels should be implemented.