Editor's Note: (This story has been updated to reflect the US Centers for Disease Control and Prevention's latest guidance as of December 21. )
(CNN) If you're wondering whether you should go to in-person religious services during the winter holidays this year, CNN Medical Analyst Dr. Leana Wen recommends thinking about it like your finances.
Just like a financial budget helps you figure out what your spending limits are, a "coronavirus budget" can help you figure out where your boundaries are in terms of potentially risky activities -- including religious services, she said. With the spread of the "very contagious Omicron variant" and high Covid-19 case numbers in general, Wen added, "we need to take additional precautions."
"If going to church is the most important thing and, unfortunately, people at church are of unknown vaccination status (and) all close together without masks, somebody who is unvaccinated could still decide 'That is the most important thing to me, so I'm going to continue doing this one activity,'" said Wen, an emergency physician and visiting professor of health policy and management at the George Washington University Milken Institute School of Public Health. "'But I'm not also going to go to an indoor restaurant.'"
For many places of worship, it's business as usual. But some churches, synagogues, mosques and other houses of worship have been offering virtual or outdoor services, and will be doing so for holiday events. Other groups still holding in-person services indoors, such as the Roman Catholic Archdiocese of Boston, have implemented mask mandates and require churches to designate areas for those who want to physically distance. The Archdiocese of San Antonio is encouraging unvaccinated people to wear masks to services and asking that sick people stay home until they haven't had symptoms for at least 24 hours.
"Pastors have the authority to grant dispensations from the obligation to attend Sunday Mass on an individual basis for those who need such consideration," according to an Archdiocese spokesperson.
This weekend, The Temple in Atlanta is hosting only virtual Shabbat worship services and Torah studies.
"Making sure that we are fully vaccinated and receive a booster if eligible to receive that at this time" is "the only thing that we have in our arsenal to protect ourselves," said Dr. Ada Stewart, a family physician with Cooperative Health in Columbia, South Carolina, and the board chair of the American Academy of Family Physicians.
Being fully vaccinated in time for December holiday services isn't possible given vaccine dosing schedules (people are considered fully vaccinated two weeks after their second dose in a two-dose series or after their single-dose vaccine). But getting vaccinated now and developing some immunity "is better than nothing," Stewart said.
"If you are unvaccinated by choice, you are potentially endangering others, and I do not believe that you should be going to nonessential public services or to nonessential public spaces," Wen said.
Here are some things to keep in mind when attending in-person religious services right now, regardless of your vaccination status.
Vaccinated and unvaccinated people who do decide to attend in-person services should get tested (by a medical professional or self-test) beforehand, Wen suggested. People who are immunocompromised -- or living with people who are immunocompromised -- should be particularly cautious regardless of vaccination status, since immune-weakening conditions make someone at higher risk for serious disease and death if they get Covid-19.
Everyone should also "follow local public health measures as well as the rules put in place by the individual houses of worship," Stewart said. These may vary and change frequently, so checking before attending a service is important.
Even if you're vaccinated, wearing a mask to protect yourself and others is still a good idea since you or others could have an infection without knowing, Wen said. Mask-wearing and physical distancing -- staying at least 6 feet away from people who don't live in your household -- are especially important if you're in an area of substantial or high transmission of Covid-19, according to the CDC.
"Quality of mask really matters. There is no place for cloth face masks at this point," Wen said. "We need to be wearing at least a three-ply surgical mask. You can wear a cloth mask on top of that, but do not just wear a cloth mask alone." KN95 and N95 masks are great options, she added.
Also, avoid poorly ventilated spaces -- well-ventilated spaces have the ability to open windows and doors and use window fans. They also have properly operating ventilation systems and HEPA (high-efficiency particulate air) filtration systems that enhance air cleaning.
Ask your house of worship whether it uses a HEPA filtration system, and if staff are regularly cleaning, with soap or detergent, frequently touched surfaces like pews, pens or offering plates. You could bring sanitizing wipes to use if needed. The risk of getting infected with coronavirus by touching contaminated surfaces is generally low, the CDC has said. But it depends on several factors, including the infection rate in your community.
The likelihood of surface transmission can be further reduced by properly wearing masks and handwashing. Before and after the service, wash your hands with soap and warm water for at least 20 seconds, or use hand sanitizer -- especially after greetings that involve touching.
The CDC has recommended a few steps to reduce the potential risk involved with sharing materials: Avoid or limit use of shared objects such as pens, hymnals, religious texts, bulletins or other worship aids. Ask whether your church can instead photocopy or electronically display or project prayers, songs and texts.
Houses of worship can also use stationary collection boxes for offerings instead of passing a basket or accept contributions online.
If food is offered at or after services, choose pre-packaged foods instead of buffet or potluck meals, if possible. During the holidays, taking communion is an important sacrament for some, but does increase risk.
"I would not advise for people to take part in gatherings with food with members of your church," Wen said, but "if you're removing your mask, everybody needs to be vaccinated and tested. Or it needs to be outdoors."
Regardless of congregants' vaccination or test status, if you take communion, do so very quickly. "Use common-sense measures that reduce your risk -- don't take off your mask for 30 minutes while awaiting communion," Wen said. "Keep it on the entire time you're there, put the wafer in your mouth and then put your mask on immediately after."
If you have children, the CDC has also provided resources for preventing the spread of coronavirus in child care settings. Whether children should attend Sunday school depends on the setting, Wen said.
For unvaccinated children older than 2, "there should be enforced masking at all times, ideally (6-feet) distancing," she said.
"Outside is much better than inside," Wen added. "If it's inside, at least have it be in a well-ventilated space. We should consider Sunday school to be the same as regular school, which is that transmission can be quite low if the proper mitigation measures are followed."
Getting tested for coronavirus at least three days after a high-exposure event is good to do so that if you're infected, you don't infect others, Wen said.