Even as some businesses called for a more immediate reopening of the economy, public health experts’ first reaction Monday to Governor Baker’s conservative plan was worry — that more interaction would make a second wave of infections possible, perhaps likely.
Scientists who have followed the disease’s spread told the Globe that Baker’s plan made sense, and they were encouraged by recent statistics showing a downward trend in infections. Still, they were unenthused with the loosening of social distancing measures and suggested that it may lead to a future spike in Massachusetts, where 5,800 people have died and more than 1,000 new infections are still reported each day.
“We’re going in the right direction but we still have a lot of cases per day," said Erin Bromage, a professor of immunology at University of Massachusetts Dartmouth. "It would be wise to get it lower before we start the interactions back up again.”
Baker’s plan allows for the immediate reopening of houses of worship, construction, and manufacturing sites, albeit with tight restrictions. Curbside retail, hair salons, and some lab and office spaces can follow next Monday under strict guidelines.
Several epidemiologists said that a return to worship services could be especially problematic — religious gatherings are the only ones in the state not limited to 10 people.
“Certainly, if you have 100 people inside a big room, that is a setting conducive for a super-spreading event," even if everyone wears masks, said Samuel Scarpino, an epidemiologist at Northeastern University.
Scarpino said he felt Baker’s guidelines were appropriate, but he thought an emphasis on screening workers for fevers and coughs could be misleading, given the high percentage of transmission caused by people with no symptoms.
“This is likely to give a false sense of security and will be frustrating when the inevitable spread happens from someone who wasn’t visibly sick,” Scarpino said, adding that mandatory masks, frequent testing, and heightened contact tracing are crucial.
On Monday, Baker acknowledged the risk of a second wave of infections as he seeks to return people to work — nearly 1 million people have been left unemployed by the pandemic. Baker said public health data would dictate when the state moves forward — or backward — in its four phases of reopening.
“These two will be inseparable: getting back to work and fighting COVID — until there is a medical breakthrough with treatments or a vaccine,” Baker said. “We cannot move forward unless we commit to continuing to slow the spread.”
Baker’s plan for the reopening of houses of worship capped attendance at 40 percent capacity. The plan also called for universal masks and encouraged outdoor services.
In a rural area with low coronavirus case counts, Bromage said, those house of worship guidelines are appropriate. But in an urban area such as Boston, with more cases, “that’s probably not enough."
Bromage said services should be as short as possible — the longer they go on, the more exposure congregants will have to an infected person in the audience. Group singing also raises risks, Bromage noted, because singing generates more viral droplets than talking or breathing.
Several large outbreaks have originated in churches. In Sacramento County, Calif., last month, 71 people connected to a single church became infected with the virus.
Dr. David Hamer, an infectious disease expert at Boston Medical Center and professor at Boston University School of Public Health, added that people should take special care in indoor spaces with less air circulation.
“Houses of worship worry me,” Hamer said. “Forty percent [of capacity] is still quite a few people.”
Hamer noted that cramped entrances and shared surfaces in religious spaces would only increase opportunities for infection.
The state’s plan allows for parks, beaches, and many other outdoor recreation sites to open beginning next Monday. Scientists said people working and spending leisure time outdoors have less to fear.
“Construction does not worry me,” Hamer said. “In most cases, construction teams can wear masks. They can maintain distance. There’s air circulation.”
Still, experts urged caution even in relatively low-risk outdoor settings.
“On the beach, people can spread out. But the flip side is, people are going to want to interact," Hamer said. He suggested that people should still be careful about shared spaces and activities.
Baker’s blueprint said he would make reopening decisions based on the continuous assessment of six key public health statistics: hospitalizations; deaths; hospital capacity; the proportion of all tests that are positive; the state’s ability to test for the virus; and its ability to trace the contacts of those infected.
Helen Jenkins, a biostatistics professor at Boston University, said she thought the public health metrics Baker used to guide the reopening were inadequate. Two of the six indicators — the rate of hospitalizations and deaths — tend to reflect what happened weeks earlier, “so if you act on those, it’s too late,” she said.
“They should be looking at more real-time measures,” Jenkins said, adding that the most important number to watch is a current estimate of “the reproductive number,” or the number of new infections caused by the typical case of coronavirus.
“This is really critical — at the moment, I’m not sure the stats he is looking at are sufficient.”
Dr. David Brown, chief of emergency medicine at Massachusetts General Hospital, praised Baker’s approach as thoughtful and inclusive of health care providers, public health officials, and business leaders’ opinions.
Still, Brown explained that an increase in virus transmission would be “inevitable" as society reopens.
“There will be some increase in the spread of the disease as we come together more," Brown said. "But we can slow that, and we can keep it manageable, and we can limit the impact if we’re thoughtful.”
Brown said he was encouraged that the state will continue to monitor indicators related to hospital capacity. “It’s one of the things that I, as an emergency physician on the front lines, anticipate and worry about,” he said.
Each of the scientists interviewed by the Globe urged people to maintain vigilance and stay 6 feet apart, wash hands frequently, wear face coverings in public, and limit indoor interactions.
“If we maintain those strategies . . . I think we can continue to slow the spread of the virus to a manageable disease burden," Brown said. “As long as we keep that number [of cases] low, or relatively low, so that we can manage those patients, then the health care system won’t get overrun as we reopen society.”