Infections in U.S. are trending downward

The worst of the current wave of coronavirus infections seems to be behind us, with the seven-day rolling average of new cases trending down in almost every part of the United States. Nationally, that average peaked Jan. 8 at nearly 260,000 new cases; the figure for Feb. 3 — 136,442 — amounts to a 47 percent drop from that peak.

Some parts of the country, including the Upper Midwest, are experiencing bigger decreases in new cases than others. Four states in the region — Minnesota, North Dakota, South Dakota and Iowa — have seen average daily cases fall by 80 percent or more.

The places with the steepest decreases tend to be small counties where the overall case count is relatively small, leading to wild swings in the data. Restricting the data to about 600 counties that had at least 100 daily cases at their recent peak shows that cases have fallen 60 percent on average.

Most of the areas showing smaller decreases experienced their winter peaks later, meaning they haven’t had as much time to come down. For example, the Midwest peaked in mid-November, while the Eastern Seaboard peaked in mid-January.

The current decline remains most pronounced in the Midwest. In Hennepin County, home to Minneapolis, daily cases have fallen to roughly 200 from 1,200. Wayne County, home to Detroit, saw a similar drop, to 220 from 1,200.

Even while U.S. cases broadly are trending downward, some parts of the country are still reporting new cases at a rate higher than during the worst peak they experienced last year. For some states that saw surges early in the pandemic when widespread testing was not yet available, these early peaks may be understated.

Maine, for example, saw relatively low case counts until November, when cases began to rise before peaking in late January at nearly 12 times the level of the state’s peak last year. Even so, its current daily case count is tame compared with some other parts of the country — such as Texas, whose rate is triple that of Maine when adjusted for population.

In New York state, areas outside of New York City weren’t hit as hard as the city was in the spring last year but faced a brutal second wave this winter. Hawaii is the only state where the first wave was more severe than the second wave in terms of reported cases.

It remains to be seen whether the new variants of the coronavirus circulating in parts of the country will trigger another surge in cases. The more contagious variant first identified in the United Kingdom has now been detected in more than half of states. On the other hand, as more people are vaccinated, transmission rates could fall. While both vaccines currently approved in the United States require two shots, studies show that even one dose offers strong protection against the virus.