Why Most Asians Have This Scar On Their Left Arm?

https://www.flickr.com/photos/theemergencyroom/2903749873
They are provided by the Ministry of Health (MOH) as part of the Expanded Programme of Immunisation (EPI). The visibility of a scar plays a role as it is an important index in the vaccination program. A child with no scar present would be given the BCG vaccine at Standard One in school.

If you find such a distinctive scar pictured above on one of someone's arms, usually their left, even on men and women of all ages, it's most probably a mark that was left due to the inoculation of the BCG, or 'bacille Calmette-Guerin' vaccine, through injection. 

Following the inoculation of the vaccine, the wound should eventually heal and form a scar that would last for a lifetime. The size and shape of the scar on the arm may differ from individual to individual, but usually people would be left with a puckered scar and its appearance is circular in shape.

But first, why BCG vaccine?
More than three billion people have been vaccinated with BCG since it was first introduced in 1921 to prevent tuberculosis (TB), a disease that spreads from person to person through the air.
According to the World Health Organisation (WHO), TB can be deadly - killing or debilitating more adults aged between 15 and 59 years than any other disease in the world.

Based on statistics provided by WHO, the largest number of new TB cases occurred in Asia (45% of new cases) followed by Africa (25% of new cases) in 2016.

WHO said that "in the global context, TB in intimately linked to poverty, and control of TB is ultimately a question of justice and human rights".

BCG is one of the most widely used of all current vaccines, but different BCG vaccination policies and practices that have been implemented vary across time and countries over the years of its existence.

For Malaysia, the BCG vaccines are given to newborns at birth.
They are provided by the Ministry of Health (MOH) as part of the Expanded Programme of Immunisation (EPI). The visibility of a scar plays a role as it is an important index in the vaccination program. A child with no scar present would be given the BCG vaccine at Standard One in school.