The fast spread of the Delta variant of the coronavirus in much of the world is thwarting plans in many countries to lift lockdowns and reopen economies, a major setback to efforts to contain the global Covid-19 pandemic.
The variant’s spread has heightened a likely feature of an extended global pandemic: the contrast between poorer unvaccinated countries where hospitalizations and death rates are surging and highly vaccinated populations where the link between rising case rates and serious illness has been largely broken.
Delta, which swept through India in May, is estimated to be at least twice as contagious as the original version of the virus.