Immunity to rubella disease among people under 25 years in Ahvaz in 2013

Background: Rubella is an important childhood infectious disease caused by rubella virus. Complications of rubella, except in pregnant women, are negligible, but its importance is due to congenital rubella syndrome. To control the effects of congenital complications, rubella vaccination program is run. The goal of this study was to evaluate the status of immunity to rubella in Ahvaz, Iran.

 Methods: In this cross - sectional study, anti-rubella IgG antibodies were investigated in 865 individuals aged 1-25 years by ELISA method. The cut-off values of more than 11 IU / ml was considered as immune. Data were analyzed by SPSS-18 software using chi-square, ANOVA and Pearson correlation.

Results: Of the study subjects, 563 patients were female (65%) and 302 patients were male (35%) with the mean age of 12.7±7.1 yr. Seven hundred fifty nine subjects (87.7%) were immune against rubella. The level of immunity to rubella was different in various age groups (p=0.0001). The highest level of immunity (97.2%) was observed in the 19-25 year-old patients and the lowest level (79.0%) was seen in the 1-6 year-old individuals. Immunity rates were significantly higher in females than in males (P=0.010). Pearson correlation showed a significantly positive relationship between age and antibody titer. The antibody titer also increased with age increase (r=0.365; P=0.001).

Conclusion: The results of this study show that rubella vaccination program has been successful to create an appropriate immunity against rubella, especially in 19-25 year-old females, the main high-risk group.