The more-transmissible Delta variant of the coronavirus is surging across Africa, the continent with the least vaccines and weakest healthcare systems, feeding fears among epidemiologists and political leaders of a public-health disaster that could echo the tragedy that unfolded in India in the spring. The speed of the takeover of the variant, which was first identified in India and is forcing governments around the globe to tighten restrictions on social and economic activities, has shocked health experts in Africa, a continent that—in part thanks to its younger population—has recorded fewer Covid-19 deaths than other regions. Some are warning that previous infection from another strain of the virus may not protect against Delta, leaving swaths of the population that were believed to be immune once again vulnerable. In South Africa, families have been driving ailing relatives across state lines to try to secure one of the country’s few remaining intensive-care beds. On a recent June night, every one of the 30 Covid-19 patients in the intensive-care unit of Uganda’s largest hospital died as the oxygen supplies ran out. In Zambia’s capital, Lusaka, doctors say the mortuaries have run out of space.