(CNN) Coronavirus restrictions are disappearing by the week in much of the world, as more Western countries scale back their remaining restrictions and inch toward a policy of living with Covid-19.
The more transmissible but less severe Omicron variant -- and its subvariant, BA.2 -- have played a large role in that calculation, convincing many leaders that endemic Covid is in sight.
But what does that mean? Some top scientists are concerned that our understanding of "endemic" is wide of the mark.
"I think we've done a huge disservice using the word 'endemic,' frankly," Michael Fraser, executive director of the US Association of State and Territorial Health Officials, told an audience of mostly public health officers during a panel discussion at the 2022 Preparedness Summit in Atlanta on Thursday.
"It's not well-understood. It's not precise," he said. "There are endemic diseases that kill 400,000 people a year, like malaria ... and there are endemic diseases like herpes or HSV-1 that are in half the population and maybe you get a cold sore."
Endemic refers to the constant presence or "usual prevalence of a disease or infectious agent" among a population within a geographic area, according to the US Centers for Disease Control and Prevention.
But it might be too simplistic a term to apply to Covid right now.
"It doesn't seem to fit," Lori Tremmel Freeman, chief executive officer of the National Association of County and City Health Officials, told CNN at the event. "No term really can just be plugged and played."
"We don't have all the pieces to this puzzle of Covid," she said. "It seems like a false narrative to talk about the end. We can plan for it, but we have to be ready to go back to measures if we see another variant or another wave."
It's a pressing discussion, given that the Western world is moving -- albeit at different speeds -- toward a pre-pandemic set of measures and rules.
European countries "brutally" ended their restrictions in the early part of this year, the World Health Organization said, and April has seen Germany scale back mask rules and the UK scrap all of its prevention measures.
The US, meanwhile, could let its mask mandate in airports and on flights lapse on Monday.
So what's the answer, according to the experts? Instead of using "endemic," Fraser said, public health leaders should focus on what "sustained management" of Covid-19 might look like.
That means exploring options like annual booster shots, keeping some prevention measures in reserve for future outbreaks -- and constant monitoring of where, when and how the virus is spreading.
"We tend to think of endemic as really just an expected disease that's out there circulating," Janet Hamilton, executive director of the Council of State and Territorial Epidemiologists, said during the panel.
"That's definitely what Covid is going to be -- but the 'expected' part is still, I think, such a big question on the table," she said.
CNN Health's Jacqueline Howard contributed reporting.
Q: Will boosters be needed more than once a year?
A: It's possible that some people will be offered frequent Covid-19 vaccine boosters, according to Dr. Leana Wen, CNN medical analyst and an emergency room physician. But there is "a lot we don't know," she said.
"Certain groups of people may need more frequent vaccines," Wen said, referring to immunocompromised people. "It's possible that, going forward, certain more vulnerable populations will be recommended to get vaccines at a higher frequency than the general population."
Wen added that there would need to be contingencies in place so that if a new variant that evaded prior immunity arose, the option to develop, manufacture and distribute variant-specific vaccines would be available, which could bring vaccine frequency up for that particular time period.
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Much of Europe remains at the CDC's highest travel risk level as other regions improve
For three weeks in a row, the US Centers for Disease Control and Prevention has not added a single new destination to its highest-risk Level 4 category for travel, Forrest Brown and Marnie Hunter report.
But as more territories come off the list, much of Europe -- including its popular travel hotspots -- remain stubbornly lodged at Level 4.
The United Kingdom, for example, has been at Level 4 since July 19, 2021.
That puts England, Scotland, Wales and Northern Ireland all in the "Very High" risk category for Covid-19. Other European countries at Level 4 include France, Germany, Greece, Italy, Ireland, Malta, the Netherlands, Portugal and Spain.
Covid lockdowns are causing chaos in the world's biggest car market
Factories shut down, new model launches delayed and sales plunging. China's huge car market has been thrown into disarray by the country's latest Covid surge, with stringent lockdowns across several cities hitting vehicle production.
China's worst outbreak in two years has prompted authorities to ramp up the country's "zero-Covid" policy, locking down several major cities and tens of millions of people.
The strict lockdown measures in places such as Shanghai and Jilin province have forced automakers to shut down manufacturing and risk delayed shipments at a time when global demand for vehicles is strong, writes Laura He.
BA.2, where are you? Dominant strain hasn't shown signs of starting a surge in the US
Maybe BA.2 really is the "stealth variant."
The Omicron subvariant caused as many as 3 in 4 cases of Covid-19 in the United States last week, according to the latest genomic surveillance from the CDC, but so far, there are no signs of a looming surge in the US.
Even as BA.2 has become dominant, overall numbers of cases are still decreasing, Brenda Goodman writes. If things stay quiet, as some models predict, it will mark the first time a viral strain has taken over in the US without causing an increase in Covid-19 cases.
Ventilated spaces help reduce the risk of transmission
We spend most of our days indoors -- so the "air we breathe indoors has a massive impact on our health," Joseph Allen, director of the Healthy Buildings Program at the Harvard T.H. Chan School of Public Health, told CNN.
A good rule of thumb, he advised, is to look at how well-ventilated a space might be. The better the ventilation, the more the air is diluted -- similar to how it is outdoors.
But tasking people with assessing their own risk can be a challenge, so having the basics of vaccinations and knowing Covid-19 infection rates is important.
Learning a new language can be really difficult, so how did we do it as children? CNN's Chief Medical Correspondent Dr. Sanjay Gupta talks to Professor John Schwieter about what's happening in the brain when we learn a new language and the potential health benefits of being bilingual. Listen here.