Background and Aims: The safe, potent and effective live vaccines against Measles, Mumps and Rubella as important childhood diseases have been available for several decades. Several factors can affect the thermal stability of lyophilized vaccine. Methods: In this study, the effect of residual moisture on thermal stability of 61 batches of MMR vaccine was investigated using an accelerated method that has been recommended by World Health Organization (WHO). Results: Our results suggest that the best thermal stability for the lyophilized MMR vaccine is in a range of 1.51 to 2.00% of residual moisture with the minimum decrease in the all three components of the vaccines. Conclusion: It is suggested that the lyophilizators of MMR vaccine production lines should be programmed in a manner that the best range of residual moisture achieves.

Objective: Viral interference has been demonstrated in different systems, such as the effect of enterovirus infection on live-attenuated oral polio vaccine. In this study, the effect of reovirus which could exist in the human intestinal tract on poliovirus vaccine strains was investigated and could be an important factor to consider in oral polio vaccination. Methods: Cells were infected with reovirus, then superinfected with poliovirus. The amount of viral yields was measured by the TCID₅₀ and plaque assay methods. Polioviral RNA synthesis was studied by real-time RT-PCR and the viral RNA load was calculated. Viral protein synthesis was determined using the techniques of immunoflourescent staining and PAGE followed by the immunoblotting experiment. Results: Poliovirus superinfection of reovirus-infected cells resulted in inhibition of poliovirus replication. It was found that the inhibitory effect of reovirus was after establishment of its infection (2 h postinfection). There was no competition between the two viruses for cell attachment but poliovirus RNA and protein synthesis were inhibited. Conclusion: Infection of cells with reovirus could interfere with the growth of poliovirus upon superinfection. This phenomenon could be important to consider when using attenuated poliovirus vaccine.

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Background and Aims: Rubella virus is a human pathogen that causes congenital rubella syndrome (CRS) when infection occurs during early pregnancy. Vaccination programs have been remarkably successful in controlling natural rubella infection and CRS. Moreover, ongoing surveillance for all cases of rubella and CRS is a vital component of a prevention program. Although the WHO recommends the use of molecular epidemiology, little is known about circulating strains and genotypes of rubella virus (RUBV) in Iran. This study was designed to analyze the genetic characteristics of the wild type isolated in Iran. Methods: The partial E1 gene was amplified from the isolated Iran MF rubella virus and Takahashi vaccine strain in comparison with 22 reference strains. The sequence of the E1 gene of the rubella virus isolate was compared by phylogenic analysis. Results: Nucleic acid sequencing confirmed the isolated virus was Rubella (96 % identity in 784 bases) the sequence was subsequently submitted and registered to the GenBank with accession number DQ975202. The created phylogenetic tree of rubella virus reference sequences showed that the isolated MF rubella virus was classified into genotype 2B. Conclusion: Based on our data, this is the first report of rubella virus genotyping in Iran. The history of some eradicated viral diseases shows that us how molecular tools are helpful in surveillance. However, more comprehensive molecular epidemiologic studies are required in order to reach Rubella virus elimination goal.