Gravediggers bury a deceased COVID-19 patient at the Parque Taruma cemetery, Manaus, Brazil, where the disease has caused a huge number of deaths.PHOTO: BRUNO KELLY/REUTERSHerd immunity is expected to arise when a virus cannot spread readily, because it encounters a population that has a level of immunity that reduces the number of individuals susceptible to infection. On page 288 of this issue, Buss et al. () describe the extent of the largely uncontrolled severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic in Manaus, the capital of Amazonas state in Brazil. Their data...…Gravediggers bury a deceased COVID-19 patient at the Parque Taruma cemetery, Manaus, Brazil, where the disease has caused a huge number of deaths.PHOTO: BRUNO KELLY/REUTERSHerd immunity is expected to arise when a virus cannot spread readily, because it encounters a population that has a level of immunity that reduces the number of individuals susceptible to infection. On page 288 of this issue, Buss et al. () describe the extent of the largely uncontrolled severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic in Manaus, the capital of Amazonas state in Brazil. Their data...WW…