RIO DE JANEIRO—In early May possibly, the new coronavirus swept through the crowded properties in Alley 24 of Rocinha, just one of the premier of Brazil’s favelas, or slum communities.

20 of the 35 users of Ivanete Dias de Carvalho’s prolonged household who are living crammed jointly here arrived down with signs of Covid-19, from substantial fevers to fluid-stuffed lungs. Handful of had been ready to get a take a look at. Her 65-yr-aged aunt died.