(NEXSTAR) – The latest COVID-19 variant of concern, omicron, has captured the attention of the globe. As one of the most mutated viruses ever seen by scientists, it’s also proving to cause more breakthrough cases, meaning those who are fully vaccinated, and even some with booster shots, are testing positive for the virus. 

According to the Centers for Disease Control and Prevention, vaccines are not 100% effective at preventing infection, meaning some who are fully vaccinated will still get COVID-19. Those that are fully vaccinated and experience a breakthrough case are less likely to develop serious illness than those who are unvaccinated and get COVID-19.

The below data from the CDC shows that breakthrough cases — among those who are fully vaccinated without a booster dose — began rising in early November and through the rest of the month. In late November, scientists in South Africa first detected the omicron variant, which was confirmed in the U.S. in December. 

The rates of COVID-19 cases by vaccination and booster status as of December 30, 2021. (Centers for Disease Control and Prevention)

“We’re seeing more breakthrough cases in people that had just had their primary vaccines,” Dr. Jim Conway, medical director with the immunization program at UW Health in Wisconsin, says. “The good news is that even if they haven’t gotten the boosters, you know, they’re still very well protected against severe disease.”

While those with the vaccine appear to be well protected, Dr. Conway says immunity is starting to wane for those who only received the first series of vaccinations. 

“You’re really not considered fully protected anymore if you only have that primary series,” he adds.

After recent studies found that experiencing a breakthrough infection can create “super immunity” to the virus that causes COVID-19, should you let yourself get sick?

Dr. Conway describes it as “not a reasonable gamble to try to make a recommendation that that’s a good idea for anybody.” He explains that natural immunity from the initial strains of COVID-19 didn’t last long — only roughly 60 to 90 days — and didn’t stand up against the delta variant. Getting COVID-19 can lead to severe disease requiring hospitalization or long-hauler symptoms. Instead, for those hoping to boost their immunity, Dr. Conway says the booster dose is the safest option.

Before you can roll up your sleeve and get a booster dose, you will need to have received either two doses of the Pfizer or Moderna vaccine, or the single dose of the Johnson & Johnson vaccine. If you haven’t gotten your primary series yet, you still have time. 

“It’s never too late to get vaccinated. There were some people who wanted to wait and see and make sure that they understood how well [the vaccines] worked. And you know that these are safe,” Dr. Conway notes. “This continues to be a pandemic, at least for hospitalized people, over the unvaccinated and certainly the unboosted.”

Additional advice for staying safe hasn’t changed. Doctors recommend wearing masks indoors and avoid crowds. Even though the shots won’t always keep you from catching the virus, they’ll make it much more likely you stay alive and out of the hospital.

The Associated Press contributed to this report.