There’s no conclusive data yet about whether Omicron is a vaccine resistant, but experts say it’s only a matter of time before such a strain appears.  

“The probability of us seeing a vaccine-resistant strain is very high,” Mark ​​Dybul, CEO of Enochian BioSciences and a professor at Georgetown University’s medical school recently told Fortune. “There’s simply no way you can have such low rates of vaccination around the world with the virus ping-ponging between vaccinated and unvaccinated people.” 

So what happens if Omicron or another variant proves to be vaccine resistant? The good news is that it won’t send the U.S. back to square one and the extreme lockdowns of March 2020, experts said.

In fact, all of the medical experts Fortune spoke with say it’s still important to get vaccinated and receive boosters if applicable—even in the face of vaccine-resistant variants. 

“It is believed that the current vaccines, Moderna, Pfizer, and Johnson & Johnson, will provide protection. It’s unknown how much. We don’t have clarity, but perhaps over the next week, we will have a bit more clarity on that,” says Dr. Neal Mills, chief medical officer at global business consulting firm Aon.

Getting vaccines and boosters is still worthwhile

Vaccines don’t operate with a simple on and off switch, experts say. Instead, their effectiveness is on a spectrum. With each variant, including Delta, vaccines can be a little less effective at preventing infection. At the same time, people’s immune response becomes weaker over time as well. 

COVID vaccines are narrow in scope and typically target one part of the virus’ spike protein, so a single mutation can reduce a vaccine’s effectiveness, says Rick Kennedy, co-director of the vaccine research group at the Mayo Clinic. Over time, as the COVID virus mutates, it erodes the vaccine’s effectiveness one part at a time—the Beta, Delta and Gamma variants have already done so. But it’s unlikely that it will happen overnight. 

“In order to make the vaccine completely ineffective, the [COVID-19 virus] would have to mutate all of those locations simultaneously. And that’s just not going to happen,” Kennedy says. 

For now, getting as many people vaccinated, and even boosted, as possible is important, says Dr. Michael Osterholm, a leading epidemiologist and director of the center for infectious disease research and policy at the University of Minnesota.

“Getting fully vaccinated and having your booster on board is a major wall against this virus in terms of what it does to you,” Osterholm says. For instance, while the available COVID vaccines may have lower protection rates against Delta infections, it does generally prevent severe hospitalization and death. Omicron may follow a similar path.

“We know what we need to do to protect people: Get vaccinated if you’re not already vaccinated, get boosted if you’ve been vaccinated for more than six months with an mRNA or two months with J&J,” chief medical advisor to the president, Dr. Anthony Fauci, said Wednesday at a press briefing focused on the Omicron variant. 

And given the waning immunity of the initial vaccine doses, boosters become even more important. “I’ve been saying since mid-summer, that this should never be seen as a booster. All along, there should have been a three-dose approach. These are not luxury doses, these are critical doses,” Osterholm says. 

It’s more than likely that, over time and through multiple mutations, the effectiveness of vaccines will erode to the point that companies like Pfizer, Moderna, and Johnson & Johnson will need to develop second-generation vaccines. But what that threshold is and how long until the U.S. crosses it is unknown, Kennedy says. 

Masking and social distancing need to be enforced too 

Once vaccines’ effectiveness dramatically slides, the U.S. will likely be in for a rough few weeks or even months. Getting a second-generation vaccine to the public would take, at the very least, months to produce and distribute.

Meanwhile antiviral pills developed by Pfizer and Merck that aim to reduce COVID hospitalizations and death may be more effective against Omicron and future strains, but the first version of those drugs are not yet in production. An FDA panel of experts only narrowly approved Merck’s drug this week, while Pfizer’s application is still under review.

“The longer term will be okay, but the next year and a half could be pretty rough,” Dybul says.

With variant-specific vaccines, oral medications, and other treatments still forthcoming, health experts say both individual Americans and businesses must get serious again about adhering to mask mandates and social distancing in order to fight COVID outbreaks. 

“The lower the effectiveness of a vaccine is, the more important masking is, the more important social distancing is,” Kennedy says. Even now, the vaccines are not 100% effective against any of the current variants and people’s immune systems vary in how they process the vaccine.

And Osterholm says Americans should use higher-quality masks. “You really do need an n95 respirator mask. Many of the cloth masks have a very low efficiency in terms of protecting you,” he says. 

One of the biggest challenges will be getting Americans to take the necessary precautions, especially as the holiday season approaches and more big employers start to return to the office in early 2022. “This pandemic, as we know it in this country, is one where most people are done with it even though the virus isn’t done with us,” Osterholm says. 

Most employers are “tight-lipped” about changing their return-to-the-office plans amid the news of the Omicron variant because they’re trying to avoid giving employees whiplash by repeatedly pushing back returns. “They’re trying to be conscientious about this, but they are very apprehensive,” Mills says. 

If companies do invite employees back to the office, Mills says workers should expect those businesses to employ safeguards like masking mandates, social distancing, COVID testing, and even vaccine mandates. 

“Delta is still gonna nail us, it’s going to be a huge challenge. But the only thing that will change that is going to be if Omicron takes it over and that will be even a greater challenge,” Osterholm says.