COVID-19 cases are rising in what experts say is a warning sign

Though vaccination has thus far staved off a rise in hospitalizations and deaths, epidemiologists warn that the current uptick in cases could still balloon into a surge.

Nurse Alyssa Velotta drew a dose of the vaccine at a clinic set up by the East Boston Neighborhood Health Center at the Wonderland Ballroom, in Revere.Pat Greenhouse/Globe Staff

Even as more and more people get vaccinations, Massachusetts is once again seeing its daily case counts of the coronavirus rise, with the average number of new infections at its highest since mid-February.

Massachusetts on Friday reported 2,301 new COVID-19 cases, bringing the seven-day average of daily cases to 1,796.7. The threat of a surge looms larger in some towns than in others: This week, the state listed 32 communities as high-risk for COVID-19, up from just 20 communities the week before.

“It is concerning,” said Dr. David Hamer, an infectious disease expert at Boston University and physician at Boston Medical Center. “If this worsens, then the governor may need to move us back to an earlier phase of opening.”

Public health experts pointed to a number of factors that could be driving infections: increased circulation of a more-contagious variant of the coronavirus; pandemic fatigue, and springtime optimism that have led the public to be less vigilant; and Governor Charlie Baker’s continued loosening of public health guidelines.

Many epidemiologists have warned for weeks that these factors could combine to produce an uptick in cases. Now, with cases rising, they said it is clearer than ever that to avoid a surge, the state must exercise caution and resist the urge to let down our collective guard.

“This was predicted. ... And in my mind, this is all so unnecessary,” said Dr. Ashish Jha, dean of the Brown University School of Public Health. “It feels like the governor has just stopped listening to public health experts. And I appreciate that he’s got to look at a broad swath of issues, but it still remains a public health problem.”

“It’s really a risky situation at this moment with these variants ... and I wish this was not the moment that the governor had decided to relax restrictions,” Jha said.

The governor’s office has repeatedly emphasized the state’s victories in combating the pandemic. COVID-19 hospitalizations are down 19 percent since March 1, and 80 percent of people over the age of 75 have received at least one vaccine dose, Sarah Finlaw, Governor Baker’s press secretary, said in a statement shared with the Globe on Friday. The state’s overall vaccination rate is among the highest in the nation.

“This progress has enabled Massachusetts to take additional steps to safely reopen our economy and the Administration will continue to carefully monitor all public health data as the Commonwealth continues to move through the phased reopening process,” Finlaw said.

As of Friday, the number of people fully vaccinated — with either two shots of the Moderna or Pfizer vaccines or one shot of the Johnson & Johnson — rose to 1,194,905. Baker officials have said they aim to vaccinate 4.1 million adults.

Governor Baker also noted in a press conference this week that many new cases are in young adults, who are less likely to be hospitalized or become severely ill.

Children and teenagers, about 22 percent of the state’s population, accounted for a quarter of new cases in the two weeks prior to March 20, the Department of Public Health’s most recent report shows. People in their 20s, about 14 percent of the population, accounted for 20 percent of new infections.

In the same time period, cases among the oldest groups, people in their 70s and those age 80 and older, dropped.

Experts agreed that high vaccination rates among the state’s most vulnerable populations will go a long way toward preventing a dramatic increase in hospitalizations and deaths in the event of another surge.

“The patterns that we’ve been familiar with before are going to be different now that vaccinations have started going out,” said Helen Jenkins, a BU epidemiologist. “What we hope to see is that the shape of the epidemic curve for cases starts to uncouple from the patterns we see in hospitalizations and deaths” as high-risk groups are protected, she said.

But experts said that preventing infections in all age groups remains a worthwhile, and even urgent, goal.

“If we have another surge, which we may be entering right now, we will still have a lot of hospitalizations, we will still have a lot of deaths,” said Samuel Scarpino, a Northeastern University epidemiologist.

People of all ages can suffer long-term health complications following a COVID-19 infection, Scarpino said, and even young people can die from the disease.

Rising infections among children and teenagers are of particular concern, Scarpino said, since plans for vaccinating them remain uncertain. Throughout the pandemic, children have played a limited role in transmission, as they are less likely to be infected than adults. But that could change, Scarpino said, due to more contagious variants such as the B.1.1.7 variant first identified in the United Kingdom.

“If we see kids and teenagers actually making up their proportional share of cases when previously they hadn’t been, that means that they are now playing a bigger role in the epidemiology of COVID,” he said. “It’s going to make it harder for us to get to herd immunity threshold in general because we’re going to have to vaccinate more people.”

The number of communities that are considered high-risk for COVID-19 has increased for two weeks in a row. Among those currently seeing high levels of community risk, some, including Lynn and Lawrence, have spent much of the past year battling some of the state’s highest rates of transmission. A number of communities on Cape Cod are also high-risk.

Several experts expressed frustration at the recent increase in infections — and the state’s continued relaxation of pandemic rules. While the state’s vaccine rollout has been encouraging and a new normal is within our reach, they said, progress is a reason to practice caution for just a few weeks longer, rather than speed ahead.

“What we need to be focused on is getting out of this, getting to the new normal. And you know, we’re just not there yet,” Scarpino said. “But we could get there faster, with a lot fewer deaths and a lot fewer hospitalizations, if we hold off on all of this widespread reopening.”