Immunization can protect against 25 different infectious agents or diseases, from infancy to old age, including diphtheria, measles, pertussis, polio, tetanus and COVID-19.

The World Health Organization (WHO) estimates active immunization currently averts 2 to 3 million deaths every year.

However, 22.6 million infants worldwide are still missing out on basic vaccines, mostly in developing countries.

[3] Previously, Immunization Week activities were observed on different dates in different regions of the world.

Immunization Week was observed simultaneously for the first time in 2012, with the participation of more than 180 countries and territories worldwide.