About 30,000 marathoners from 122 countries and all 50 U.S. states will hit the streets on Monday in and around Boston, where the city’s Public Health Commission reports that the Covid positivity rate has risen to 6.6 percent, passing its “threshold of concern” of 5 percent.
The agency urged residents to mask, to test before joining indoor gatherings, to gather outdoors if possible, and to get booster shots to protect themselves and others in the coming days as Easter, Passover, Ramadan and public school vacations converge. The city’s positivity rate has risen by 4 percentage points since early March, it noted.
This month the Omicron BA.2 subvariant has flattened the steep downward glide in official case counts that Boston and the rest of the country had been on after the BA.1 surge in the winter. The turn is not unexpected, but it comes as in-person gatherings have resumed, vaccinations have flatlined, officially reported tests are falling and politicians and many Americans want an end to most restrictions.
And while hospitalizations and deaths remain on the decline nationally, concerns are rising for unvaccinated and unboosted people, who remain more vulnerable to serious illness and death.
BA.2, which is more transmissible and has spread even faster than BA.1, has quickly risen to account for what the Centers for Disease Control and Prevention estimates to be 86 percent of all U.S. cases. Twenty states, including the entire Northeast, have seen their daily cases rise by at least 30 percent in the past two weeks. Experts believe that two new subvariants may be contributing to this growth.
The rise of at-home testing obscures the data, and suggests that the true case increase may be far higher. Some newly available treatments are most effective when administered early in an infection, making testing more urgent.
“We’re right to be worried about our publicly available test results,” said Dr. Cassandra Pierre, the associate hospital epidemiologist and director of public health programs at Boston Medical Center, who emphasized that nationally, testing capacity has diminished. “I’m absolutely concerned because I see transmission in family and work groups, and to vulnerable people.”
At the height of the Omicron wave in early January, the United States was administering an average of 2.5 million tests per day. That number has dropped to an average of about 540,000 at the start of this week, according to the C.D.C.
Notable efforts to brake cases popped up this week, including the C.D.C.’s two-week extension of the federal transportation mask requirement; the White House’s renewal of the Covid public health emergency for at least three more months; Philadelphia’s announcement that its indoor mask mandate will return; and several universities’ reinstatement of their mask policies.
“Philadelphia is really the way it’s supposed to work,” said Samuel Scarpino, the vice president of pathogen surveillance at the Rockefeller Foundation’s Pandemic Prevention Institute. “The thing they do well is that they have public, published measures that say: If we hit this, the masks go on. People are ready, and it’s not a surprise.”
The C.D.C., as of Thursday, does not recommend mandated masking for Philadelphia, nor for almost the entire rest of the country. Using data on new Covid-related hospital admissions and the percentage of hospital beds occupied by Covid patients, it says that only 0.4 percent of counties in the United States have high community levels of the virus.
“When you use hospital-based metrics, you may be losing the story of what’s happening in a vulnerable community,” Dr. Pierre cautioned. She said that state and county data has become even more obscured because many states are phasing out testing, and because community testing centers have closed after the federal government ended a program that reimbursed providers for virus-related care for the uninsured.
BA.2 set off case surges earlier this year in Europe, where pandemic trends have acted as a harbinger for the United States. Americans have lower booster coverage than Europeans, Dr. Scarpino noted, and less immunity because more time has elapsed since most people got their second or third doses. “The risk is higher here than in the U.K. and in Europe,” he concluded.
Massachusetts, where new infections and positivity rates are rising, is offering family-friendly vaccination clinics at zoos, bowling alleys and Six Flags New England during next week’s school vacation period. The state is offering gift cards and free admission to some of the attractions, reminiscent of last year’s incentives when vaccines became widely available.
“It makes sense that we want to move forward because we can’t constantly stay on red alert,” Dr. Pierre said. “But this is not the time to do that.”
“There’s this assumption that future variants will be kinder and gentler, but there’s no evidence of that. What we experience now is something different from what we might experience in the fall or winter.”