Many of the states that have suffered the worst recent coronavirus outbreaks have seen notable declines in new cases and hospitalizations over the last two weeks, according to a New York Times database.
In Michigan, which has had one of the country’s steepest drops, the average number of daily cases sank 45 percent and hospitalizations tumbled 32 percent over that time period, as of Tuesday.
The average number of new cases is down 30 percent in Minnesota, 38 percent in Pennsylvania and 33 percent in Florida in the past two weeks. In the same three states, hospitalizations are down 20 percent, 27 percent and 11 percent.
The progress for states like Michigan, which recently began to recover from one of its worst stretches in the pandemic, could indicate that vaccinations are beginning to rein in the virus in the United States. Hospitalization data can often lag behind case numbers for a number of reasons.
The director of the Centers for Disease Control and Prevention, Dr. Rochelle Walensky, testified at a Senate hearing on Tuesday that while she was encouraged by the gains against the pandemic, she urged Americans to remain vigilant to the threat of the virus around the world.
Ms. Walensky said getting a vaccine was the fastest way to end the pandemic.
“But even with this powerful tool, while we continue to have community transmission, we must also maintain public health measures we know will prevent the spread of this virus, mask hygiene, hand hygiene, and physical distancing,” she said.
Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said in an interview that the vaccines were a key contributor to improvements in case numbers and hospitalizations, but that the virus had behaved in surprising ways and there remained aspects about which experts still needed to learn more.
As an example of the virus’s unpredictable ebbs and flows, Dr. Osterholm pointed to Indiana, which borders Michigan and has lower vaccination rates but did not see the same recent spike in case numbers as its northern neighbor.
“I don’t see us having a national surge. We’re not going to be like India. I do think the vaccine levels have surely helped us tremendously in taking that off the table,” Dr. Osterholm said. “But I do think at the state level, where we have substantial populations that need to be vaccinated, we could still see substantial activity.”
After reaching an average peak of 3.38 million doses reported a day in mid-April, the pace of U.S. vaccinations had declined. Nearly all states now have a glut of vaccine doses that could be quickly redirected to adolescents after the Pfizer-BioNTech vaccine has been authorized for 12- to 15-year-olds.
President Biden is pursuing a strategy focused on local outreach and expanded accessibility to the vaccine to help reach his goal of at least partly vaccinating 70 percent of Americans by Independence Day.
Making it easier to get vaccinated could appeal to the roughly 30 million Americans who say they would get the shot, but have not yet done so for myriad reasons. Local officials and private businesses are also offering a wide range of different incentives, like free subway rides, beer, baseball tickets and cash payouts, to convince more reluctant Americans to get vaccinated.
The changes in the trajectory of the virus in the United States come as other regions of the world, especially India and Southeast Asia, are getting hit hard. A number of variants are also spreading around the world, and scientists told a U.S. congressional panel on Wednesday that variants will pose a continuing threat to the nation.
Dr. Tedros Adhanom Ghebreyesus, the director general of the W.H.O., said on Monday that the world was seeing a plateau in known cases, “but it is an unacceptably high plateau with more than 5.4 million cases and almost 90,000 deaths last week.”
He continued, “Any decline is welcome but we have been here before, over the past year many countries have experienced a declining trend in cases and deaths, have relaxed public health and social measures too quickly, and individuals have let down their guard only for those hard won gains to be lost.”