The chief scientist of the World Health Organization (WHO) is warning of “even more dire situations” worldwide in the Coronavirus pandemic if high-income countries start administering vaccine boosters ahead of poorer countries without vaccines.

With the US health officials recommending booster shots for all Americans who have already been vaccinated, Dr. Soumya Swaminathan expressed concern that leaving billions of people in the developing world unvaccinated could foster emergence of new variants, like the Delta variant, that is driving new cases in the United States and beyond.