New Jersey has reported a record-high number of positive COVID-19 cases in one day.

State health officials reported 15,482 new positive PCR tests on Thursday. It is the highest number of cases ever reported in a single day in the state. It is a nearly 60% increase over the number of cases reported on Wednesday.

But the state Health Department says that it is important to put these numbers in context.

“Testing was less widely available in prior waves, so it is difficult to compare the number of infections between now and prior phases of the pandemic. It's important to remember that at the height of the pandemic in March of 2020 there was very little testing available,” a spokesperson for the department wrote in a statement to News 12.

Other key metrics regarding the virus are also rising. State data shows that another 141 people were admitted to the hospital for COVID-related issues in the last 24 hours. More than 2,200 COVID-19 patients are currently in the hospital. That figure was around 1,800 less than a week ago.

Around this time last year, there were around 3,000 COVID-19 patients in New Jersey hospitals.

LIVE UPDATES: COVID-19 developments in New Jersey

But health care experts say that they are concerned about the Omicron variant of the virus and fear that it will spread as families gather for Christmas.

“Omicron is a lot more infectious, so it spread more quickly. It can be caught by people who’ve had a two-course vaccination dose… The important thing to note is it’s decreased in people who are vaccinated and it’s really decreased in people who’ve had the booster shot,” says Dr. Gian Varbaro, of Bergen New Bridge Medical Center.

Currently over 70% of New Jersey residents are fully vaccinated. More people are also getting tested for the virus ahead of Christmas. Varbaro says that this is a good thing.

“When you get tested more, you pick up more cases and that’s been a function we’ve known since the beginning of the pandemic,” Varbaro says. “Robust testing is actually one of the things that helps us control…the spread, so it’s not a bad thing.”

As cases of the virus surge around the state, several municipalities have reinstated some COVID-19 policies, such as indoor mask mandates. But health experts say that vaccination is the best defense.

“Vaccines No. 1 – really high up. Testing and ventilation, probably in the middle. Masks – a little less than the other ones, but still pretty effective,” Varbaro says.

On Thursday, the Centers for Disease Control put out new guidance for health care workers who test positive and have to quarantine. Isolation protocol now calls for asymptomatic health care workers to return after seven days of testing positive if they have a negative test result. Those who are fully vaccinated with a booster don't need to quarantine after being exposed.