Wednesday is World Health Day, the second amid the COVID-19 pandemic. This year's theme is "Building a fairer, healthier world."

As of April 1, over 2.8 million people had died from the virus. COVID-19 has hit all countries hard, but its impact has been harshest on those communities which were already vulnerable, who are more exposed to the disease and less likely to have access to quality healthcare services.

The tree map shows cumulative administered doses per 100 people in different economies, grouped by their economic status defined by the World Bank. Each rectangle represents one economy. Due to limited space, some names are not shown.

As of April 1, of the half billion vaccines administered, 86 percent were in high-income economies and 0.1 percent in low-income economies.

The World Health Organization has called on governments and international organizations to work with affected communities and individuals to address the root causes of the inequities and to provide equitable access to COVID-19 vaccines within and between countries.

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Graphics: Yin Yating, Hu Xuechen