President Biden and his administration on Monday warned that rising COVID-19 transmission has put the nation on the verge of giving up its “hard-won gains” in the fight against the virus, and they urged state and local leaders not to prematurely let up on public health measures.
Biden, noting that there will be enough vaccines available to provide doses for nine of 10 US adults by April 19, implored leaders of state and local governments to continue requiring face coverings in public.
Biden’s stark warning over “reckless behavior” came as Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, described a “recurring feeling . . . of impending doom.”
“We have so much to look forward to, so much promise and potential of where we are and so much reason for hope,” Walensky said during a White House news briefing, her voice breaking at times. “But right now, I’m scared.”
As increasing vaccinations have put the pandemic’s end within reach, states including Massachusetts have steadily been accelerating their economic reopenings — and many people have also relaxed their personal precautions. In recent weeks, new cases have begun to mount after a period of relative stability.
The seven-day average of new cases in the United States is slightly less than 60,000 per day, which is about a 10 percent increase compared to the previous seven-day period, Walensky said. Several states are seeing more dramatic increases — Massachusetts among them, with a 15 percent increase in average daily cases from Friday, March 19 to Friday, March 26.
The state on Monday reported 1,464 new cases, 675 total patients hospitalized with COVID-19, and 15 new deaths. Hospitalizations have increased slightly in recent days, while deaths continue to decline — a trend experts say could be a sign that vaccinating the highest-risk state residents is preventing severe infections even as cases rise.
Epidemiologists have warned for several weeks that progress on vaccinations might not be enough to blunt other factors that could increase the risk: The continued reopening of the economy. The public’s fatigue with social distancing and other precautions. And — perhaps most importantly — the highly contagious B.1.1.7 variant of the coronavirus that is believed to be making up an increasing share of total infections.
Increasingly, the data are backing up experts’ concerns that without extreme caution and rapid vaccine distribution in the coming weeks, another COVID-19 surge could hit before widespread immunity does.
“The effort to get vaccine out before the variants become even more prominent is really a race,” said Dr. Marc Lipsitch, a professor of epidemiology at the Harvard T.H. Chan School of Public Health. “So everything that we have been saying for a while about the need to get vaccines out quickly and equitably to as many people as we can is even more true now.”
National voices have also joined the chorus in urging caution.
President Biden on Monday reminded the country that despite progress, “The war against COVID-19 is far from won.” In a White House announcement, he asked states that have relaxed mask-wearing mandates and other public health interventions to reverse course.
Experts said they understand the need for optimism and the temptation to breathe a sigh of relief. But as important as it is to be hopeful, they said, it is crucial to stay alert to ongoing risks.
“We are in a really critical time in the pandemic,” said Dr. Amber D’Souza, a professor of epidemiology at Johns Hopkins’ Bloomberg School of Public Health. “We are not yet at the levels of vaccination to achieve herd immunity and reduce transmission from vaccination. We are on the path. We are going to get there from vaccination, but we are not there yet.”
There is no consensus on exactly what level of immunization will prevent further surges. The herd immunity threshold — the point at which enough people are protected against the virus that it effectively can no longer spread — is estimated to be anywhere from 60 to 90 percent for this virus. Significant reduction in transmission could happen sooner, experts said, but it remains to be seen how soon.
With nearly 1.3 million adults fully vaccinated, Massachusetts outranks most other states for per capita vaccination. Even so, recent increases in infections have made it apparent that the state’s journey toward beating the virus is not yet over.
Governor Charlie Baker has moved forward with reopening the economy in recent weeks, most recently clearing the way for sports stadiums and arenas to welcome back small crowds, even as he has urged residents to remain vigilant and to avoid high-risk activities.
People in Massachusetts are required to wear face coverings in all public places.
As of last week, 32 communities in the state are considered high-risk for COVID-19, with dozens of others in the moderate risk category. A number of high-risk communities are clustered on Cape Cod, a region whose population skews older, but also one that leads the state in vaccination rates.
A Cape health official on Monday called for an emergency vaccine site to help combat the concerning uptick in transmission before it balloons into a deadly surge.
“It’s concerning when I look at the statistics for Yarmouth and then I look at what else is happening on the Cape over the last two weeks,” said Yarmouth Health Director Bruce Murphy. “We need to get ahead of this now.”
Boston, by contrast, has thus far escaped the worst of the state’s new outbreaks. Cases are increasing there, but at a rate that currently puts the city among those communities considered at moderate risk.
“We’ve doubled down. We have done so much messaging and so much outreach, and we haven’t stopped,” said Marty Martinez, chief of health and human services. Martinez said that effective vaccine distribution drives and a strategy of easing pandemic restrictions more slowly than the state have also helped the city keep transmission in check.
Still, in the past week, the city’s share of COVID-19 tests that are positive edged above 4 percent for the first time in six weeks.
“That’s starting to give us some pause about whether or not we’re going to see an uptick — and hopefully not another surge, if you would — but we’re concerned,” Martinez said. “Bostonians are doing all the things we’re asking them to do. We just need them to do it a little bit longer.”
Lipsitch, the Harvard epidemiologist, said that message applies to the state and nation.
Following social distancing guidelines and getting tested as often as needed remain as important as ever, Lipsitch said, and perhaps even more so, due to highly contagious variants.
“If you think of it as, you to start a fire with a hotter spark, this is a hotter spark,” he said. “All those factors, I think, are going to make the next few weeks definitely a period of high risk.”
Amanda Kaufman and John Hancock of the Globe staff contributed to this report. Material from The Washington Post and The New York Times was also included.
Dasia Moore is the Globe Magazine's staff writer. E-mail her at firstname.lastname@example.org. Follow her on Twitter @daijmoore.