EVALUATION OF POTENCY OF MUMPS VACCINE USED IN IRAN: COMPARISON OF WHO AND NIBSC METHOD IN CELL CULTURE

Vaccination against mumps is included in world health organization (who) program ofglobal immunization. safety and efficacy of vaccines must be confirmed by control units in charge ofpublic health. in iran, the secondary control on potency of vaccine has not been set up yet. we decidedto overcome this problem by developing who and nibsc methods in food and drug control lab.nine dilutions of vaccine from 10-1 to 10-5 in 0.51oglo steps were mixed with vero cell suspension. inwho n1ethod, the cell suspension was seeded in octaplicate (8 wells of each dilution) in 24-well plateand incubated at 36°c for 10 days, during which the cells were checked for cytopathic changeseveryday and positive wells were recorded. we used 5% serum and 1 x 105 cells for the assays. the testwas repeated with six different vaccines produced in one batch. the mean potency was 10 4.475±o.134ccidso/vial for each ten-dose vial. for nibsc method the dilutions of vaccine were added tohexaplicate (6 well per dilution) in 24-wells plate. after 3 hours, the medium was removed and overlaywas added. then the plates were incubated at 35°c for 10 days. after incubation period, the plaqueswere stained with methyl violet and counted. this assay was repeated three times and the mean ofresults was 5.93 10g1o pfu/dose. results indicate that the potency of the vaccine is in acceptable rangein either method. who method is simple and less time consuming compared to nibsc method.