---

Background: Noticing the sensitivity of measles virus to temperature and light, maintaining its stability is highly important in live vaccines. The aim of the study is to evaluate the stability of measles vaccine produced by AIK-C strain. Materials and Methods: In this experimental study, three lyophilized vaccine vials were incubated at 37˚C for one week and their stability was evaluated via accelerated test. In addition, reconstituted vaccines were incubated at 4˚C, 25˚C, and 37˚C for 0, 4, 8, 12, 16 hours after reconstitution and their remaining infectious virus titer was measured using CCID50 method. Half-life of the reconstituted measles vaccine was evaluated according to linear regression analysis. Results: When the reconstituted vaccine was incubated at 4˚C, 25˚C, and 37˚C, the titer loss per hour was equal to 0.05, 0.1 and 0.2 Log10 CCID50, respectively. Also, the half-life of this vaccine at these temperatures was 5.31, 2.26, and 1.36 hours, respectively. Conclusion: The loss of potency for measles vaccine produced by AIK-C strain is 0.33 Log after storage at 37°C for one week, while the reported amounts for commercial vaccines such as Mevilin-L, Attenuvax, Edmonston-Zagreb, and Rimevax are 0.7, 0.7, 1 and 0.78, respectively. Lyophilized and reconstituted vaccine containing AIK-C strain is more stable in comparison with Edmonston B, Schwartz, Biken-CAM, and Leningrad strains. The stability of the reconstituted AIK-C strain vaccine is similar to Moraten strain at 37˚C.