Moderna, whose coronavirus vaccine appears to be the world’s best defense against COVID-19, has been supplying its shots almost exclusively to wealthy nations, keeping poorer countries waiting and earning billions in profit.

After developing a breakthrough vaccine with the financial and scientific support of the U.S. government, Moderna has shipped a greater share of its doses to wealthy countries than any other vaccine manufacturer, according to Airfinity, a data firm that tracks vaccine shipments.

About 1 million doses of Moderna’s vaccine have gone to countries that the World Bank classifies as low income. By contrast, 8.4 million Pfizer doses and about 25 million single-shot Johnson & Johnson doses have gone to those countries.