Publisher Health

Epidemiologists are starting to hug again.

They’re also running errands, gathering outdoors with friends and getting haircuts in far greater numbers than before.

In a new informal survey this month by The New York Times, 723 epidemiologists in the United States responded to questions about their life now and how they are navigating this in-between phase of the pandemic, when vaccines have become widespread and cases are declining nationally, but herd immunity is not assured and Covid-19 remains a threat.

We have surveyed these public health experts periodically throughout the pandemic. As a group, they remain conservative in their choices about how to behave safely, and are more cautious than many Americans, whether by preference or necessity. But their increasing willingness to return to more prepandemic activities shows that even people most aware of what could still go wrong are starting to become more optimistic.

“Vaccines have given me freedom,” said Dianne Neumark-Sztainer, who leads the epidemiology division at the University of Minnesota. “I was very strict all year but am now returning, slowly, to life.”

What was making them most comfortable, they said, was vaccines. “I am feeling very hopeful about the prospect of Covid-19 being controlled as a result of public uptake of vaccination,” said Lindsey Ferraro, an epidemiology graduate student at the University of Alabama at Birmingham.

When enough Americans become immunized and infections decrease, they said, the country could enter a new phase, when coronavirus precautions would become less about minimizing risk as much as possible, and more about making choices based on one’s individual risk tolerance and health profile.

“I balance risks very carefully with benefits,” said Luther-King Fasehun, a doctor and an epidemiology Ph.D. student at Temple University. “I have my master’s level health economics training to thank for this. Some benefits are almost always worth it.”

Over all, the epidemiologists’ advice was to hold on to most precautions just a little bit longer, particularly when it comes to indoor activities or those with large groups of strangers.

“There is a strong likelihood that we will experience unexpected problems due to moving about as if the Covid pandemic was no longer a threat,” said Jana Mossey, an epidemiologist who retired from Drexel University.

But for some activities, federal health officials have begun updating their advice to the public and allowing more freedoms. The guidance has been somewhat vague, so we asked epidemiologists to expand on it.

The Centers for Disease Control and Prevention said that fully vaccinated people could gather indoors with other vaccinated people without precautions, but it did not specify how many households could do so at once.

In the survey, a plurality of epidemiologists said they would recommend limiting such gatherings to two households at a time. But a sizable number said larger gatherings among vaccinated people were OK.

“There are no magic numbers here,” said Noelle Cocoros, an epidemiologist at Harvard. “Establishing some guidelines are important, but as soon as you put a number on something, it becomes gospel for many people and impacts their understanding of risk.”

Some said the issue wasn’t about vaccine effectiveness, but about how to know and trust that everyone at a large gathering was fully immunized.

“Vaccinated people are quite safe,” said Maria Glymour, an epidemiologist at the University of California, San Francisco. “If you know everyone’s vaccinated, it’s OK. I’d just worry that with a large group, you of course cannot know that.”

Those who said that vaccinated people should continue to limit the number of people they see indoors noted that vaccines aren’t 100 percent effective, and that the more people are in a space, the more chances the vaccine has to fail. Many said they would hesitate to gather indoors until children could also be vaccinated. (The F.D.A. approved use of the Pfizer vaccine for children 12 to 15 this week.)

“It is not ‘one size fits all,’” said Alicia Riley, a sociologist and epidemiologist at the University of California, San Francisco, expressing a version of the profession’s unofficial motto: It depends. “How safe it is depends on the local levels of community transmission.”

The C.D.C. has also said that people no longer need masks when they are outdoors and can maintain physical distance from others, like on a walk, regardless of whether they’re vaccinated. Most epidemiologists agreed.

“This policy was always idiotic,” said Joe Lewnard, an epidemiologist at the University of California, Berkeley, who supported maskless exercise.

Others disagreed: “Even with the vaccine, we still have to be concerned about some of the variants to which the vaccines are less effective,” said Lorraine Dean, an epidemiologist at Johns Hopkins. “I still plan to wear my mask for quite a while.”

More said masks were necessary in outdoor situations when distance couldn’t be maintained, like picnicking or hiking. A quarter said masks were always necessary then.

“Think of always ensuring two of three: masks, distancing, outdoors, particularly if among nonvaccinated individuals,” said Eyal Oren, an epidemiologist at San Diego State University.

When it comes to outdoor activities with large crowds where it is hard to maintain distance, like at a concert or protest, the epidemiologists were almost all in agreement that masks were still necessary, regardless of vaccination status. Some suggested continuing to avoid such events if possible. “There will almost certainly be vaccinated and unvaccinated people mixing in such an event,” said Steve Ostroff, an epidemiologist with a private consulting practice.

The endless decision-making about how to behave in the pandemic remains complicated. But risk calculations are beginning to change. Eventually, pandemic decision-making for vaccinated people could become less about protecting society at large, and more about one’s own willingness to take on risk.

“I think that when all the high-risk groups are vaccinated, it is time to shift attention to letting everyone decide for themselves what risks they are comfortable with for themselves,” said Anders Huitfeldt, an epidemiologist at the University of Southern Denmark.

Some epidemiologists say this shift can happen as soon as individuals are vaccinated: “Being vaccinated should throw open the floodgates to everything you could do before,” said Zachary Binney, an epidemiologist at Emory.

But many said coronavirus precautions remained important for protecting high-risk people and slowing the virus’s spread, even for vaccinated people: “While I am comfortable taking personal risks, I would not tolerate risks that could harm others,” said Kevin Andresen, who leads the Covid response team at the Colorado Department of Public Health. “Covid precautions protect everyone, not just me.”

Assessing and balancing risk trade-offs is a key part of epidemiologists’ training. But even among epidemiologists, comfort with risk varies by the individual. Over all, 71 percent of the epidemiologists who completed our survey said they were extremely or somewhat risk-averse — especially when it comes to Covid-19.

“I live in Hawaii and free-dive with sharks,” said F. DeWolfe Miller, an epidemiologist at the University of Hawaii. “Preventing Covid transmission is another matter.”

Respondents said their Covid-19 risk tolerance was informed by the particulars of their daily life, like their need to work outside the home or the health status of their family members.

“I would be more comfortable taking risks if I did not have young, unvaccinated children whom I want to keep healthy and who need to be in day care for me to keep working,” said Stephanie Leonard, an epidemiologist at Stanford.

For some questions, variations in individual risk tolerance drove a large difference in answers. Epidemiologists who described themselves as risk-averse were nine points more likely than those who were more comfortable with risk to say that vaccinated people should limit indoor social gatherings to just one other vaccinated household, for example.

But on other questions, the experts were more united: They are almost all staying away from indoor fitness studios and say masks are still necessary in large crowds, even outdoors.

Their day jobs also influenced the risk they were willing to take. We surveyed two different groups. Members of the Society for Epidemiologic Research work primarily in academic research. The Council of State and Territorial Epidemiologists mainly works for governments that are trying to make decisions about how to balance reopening businesses and schools while still protecting public health. Members of the latter group have had to become more comfortable with accepting some level of risk.

Among the differences, government epidemiologists were 19 percentage points more likely than academics to have worked in a shared office in the last month. And 8 percent of the academics said fully vaccinated people should still avoid socializing indoors, while just a single government epidemiologist said so.

The epidemiologists are highly aware that risk is inherent in many things people do. More than at any time in the last year, most are feeling hopeful that Covid-19 will eventually become just another risk in daily life, but not one that paralyzes us.

“We’ve all learned how very resilient we are,” said Jane Clougherty, who teaches public health at Drexel University. “This too shall pass, and we are finally seeing the evidence.”