The vaccination is a global issue of controlling infection agents and non-infectious diseases that require modern technologies and scientific knowledge. During the COVID-19 pandemic the work is continuously implemented to control the situation. The vaccination can affects controlling outbreaks all around the world. Besides, applying several types of vaccines in various countries to control second peak of the pandemic can be considered as significant factor that positively impacts host immune response. However, there are different barriers to vaccination programs worldwide in areas of economy, technology, politics, demography, psychology, especially in countries with low economic level. Although vaccination program started in many countries, developing mass immunity in society is essential for pandemic termination. Iran and Russia also are involved in COVID-19 pandemic disease since January 2020, and they are still working to achieve mass immunity. The actual study was carried out to compare vaccination extent between Russia and Iran countries to evaluate vaccination impact on the COVID-19 pandemic and to review some main factors that influence vaccination to understand main barriers of vaccination in both countries.
Keywords: COVID-19; Iran; Russia; mass immunity; program; vaccination barriers; vaccine hesitancy.