Preliminary assessment evaluation of the quality of Thailand SPF chicken eggs used in the measles bulk vaccine production at POLYVAC

Abstract

POLYVAC is producing Measles vaccine using chicken embryo cells from SPF eggs imported from Germany. To have more suppliers, research was conducted to evaluate the suitability and quality of Thai SPF eggs with the production of the Measles Bulk. Thai Eggs achieved the internal standards: rejection due to cracks < 10%, eggs without embryos or with dead embryos < 15%. Thai SPF eggs were used for four production tests with two concentrations of 20 x 104 and 25 x 104 cells/ ml, and two MOI concentrations of 0.002 and 0.003 in parallel with the standard operating procedure. The results: production test with a concentration of 25 x 104 cells/ml and MOI concentration of 0.003 had a bulk product titre of 5.71lg PFU/0.5ml, which is equivalent to the titre of 5.77 lg PFU/0.5 ml of the standard operating procedure using German SPF eggs. Cell growth during each stages from Thai SPF eggs meet the standards (CGI – Cell Growth Index > 50%); sterility, not contaminated with mycoplasma, hemadsorption virus and extraneous agents… meet the WHO and Japanese standards. These results are the basis for POLYVAC to validate the material at the production scale, moving towards officially using Thai SPF eggs in the production of the Measles bulk vaccine.