The World Health Organization on Wednesday called for a global moratorium on countries offering third doses—booster shots—of COVID-19 vaccines to their general populations until at least the end of September.

The call comes in light of the vast inequity in vaccine distribution worldwide, with high-income countries gobbling up the majority of supplies. In a press briefing Wednesday, WHO Director-General Dr. Tedros Adhanom Ghebreyesus highlighted that 4 billion COVID-19 doses have gone into arms, but more than 80 percent have gone to high- and middle-income countries, which make up less than half of the world’s population.

Put another way, high-income countries have now administered 100 doses per 100 people, while low-income countries have administered 1.5 doses per 100 people due to low supply, Dr. Tedros said.