After a punishing fall that left hospitals struggling, some Midwestern states are seeing a decline in new coronavirus cases. But the signs of improvement are offset by the infection’s accelerating spread on both coasts. States including Iowa, Michigan, Minnesota and Nebraska have seen decreases in the number of people testing positive for COVID-19 over the past couple of weeks. All, however, are still experiencing an alarming number of deaths and hospitalizations because of the earlier surge of cases.