Serological assessment of rubella immunity in Iranian children post 2019 elimination: A pilot study.

BACKGROUND AND AIM: The elimination of rubella in Iran, achieved in 2019, represents a significant public health success. A limited number of studies have investigated rubella IgG seropositivity levels in Iran across different populations over the last two decades. This study evaluated rubella vaccination coverage and immunity status among Iranian children born between 2016 and 2021, before and during the COVID-19 pandemic.

METHODS

Using ELISA, 722 serum samples from children negative for measles and rubella IgM antibodies were analyzed for rubella-specific IgG. Samples were divided into two groups: Group A (born 2016-2018, pre-pandemic) and Group B (born 2019-2021, during the pandemic). Vaccination status was obtained from parental reports.

RESULTS

Overall rubella IgG seropositivity was 75.3 %, with Group B showing significantly higher immunity (82.4 %) than Group A (68.6 %) (p < 0.001). Parental reports indicated MMR vaccination coverage of 95.7 % overall, with Group B coverage (98.9 %) significantly exceeding Group A (92.7 %) (p < 0.001). No significant gender differences were observed. Regional vaccination coverage varied, but rubella IgG positivity was consistent across provinces.

CONCLUSIONS

Despite maintaining high MMR vaccination coverage, the overall rubella immunity level in Iranian children in this pilot study remained below the WHO's recommended herd immunity threshold, posing a potential risk for rubella re-emergence. This finding underscored the ongoing surveillance and targeted immunization efforts to sustain rubella elimination in Iran.