Experimental preparation of Killed-Rotavirus vaccine and evaluation of immune potential compared to a current available Rotavirus vaccine

Abstract

RV is one of the commonest virusescauses a severe diarrheal-illness, especially in children under age of 5 years. RVGE is self-limiting illness; however, death of untreated cases with severe dehydration might be resulted. RV-related death is more common in developing-Africancountries, where individual income and healthcare is limited. To protect against RV complications and deaths, RV vaccination in neonatal-life is strongly recommended. Currently, variant attenuated RV vaccines have been approved for immunization against RVGE, as Rotarix® and Rotateq®.The RV immunization with attenuated vaccines in African countries is restrictedas result of the vaccine efficacy limitation among these populations; high vaccination cost, which does not match the individual income there; immunodeficiency/malnutrition problems in most African children, so constricted administration of active-virus vaccines; intussusception side effect that is a life-threatening condition; and virus reassortment events that might develop a novel RV strains with un-expected pathogenicity. To bypass most of these current frailtiesthose related mostly to the active-virus presence, the alternative inactivated-RV vaccination approach was endorsed. Dependently, the goal of the present study is to develop a pentavalent-IRVV that containing the most circulating RV strains within the Egyptian environment. Moreover, evaluating its effectiveness compared to a currently used attenuated vaccine.The designed-IRVV antigen pool were including G1/G2/G3/G9/P[8] antigens. That was achieved by isolating RV strains that having the selected G/P antigens from RV-positive fecal samples.These samples were collected from children hospitalized with severe gastroenteritis. The experimental preparation and formulation of the thermally-treated RV vaccinewas performed using the produced antigens pool.As an attempt for improving the IRVV immunogenicity, Alum-adjuvant was added. The experimental IRVV/IRVV-Alum immune potential was evaluated using the mice model. While three equal doses of Alum adsorbed and non-Alum adsorbed IRVV were injected subcutaneously at 0, 21, 35 time intervals,the reference Rotarix® group was vaccinated twice at 0, 28 time intervals. The collected sera wereprocessed using ELISA technique for evaluating RV specific-IgG that reflect the established immunogenicity against RVI.As result of the trial IRVV/Rotarix® difference in antigenic content and doses regimen, the comparative evaluation was reliant on achieving the IgG immunization level of 1:6400.