NEW YORK (CBSNewYork) — Health officials warn the contagious Delta variant now accounts for nearly half of new COVID cases in New York City.

With coronavirus restrictions all but gone, the pandemic has started to feel like a thing of the past, but the highly contagious Delta variant is quickly becoming more prominent in the city.

READ MORE: What Is COVID’s Delta Variant?

Thursday afternoon, City Council member Mark Levine, who chairs the health committee, tweeted, “Weekly update on variants in NYC shows Delta continuing to rise fast. Now 44.4% of cases, up from 22.7% in prior week. We need to take this seriously. If you are unvaccinated, the time to get your shot is NOW.”

It is believed to be the most transmissible variant yet.

“Delta is concerning because it appears to be more infectious, and some evidence from the U.K. suggests that it causes more severe disease,” CBS2’s Dr. Max Gomez said.

Experts say the vaccines appear to be effective against the Delta variant, which has spread to at least 85 countries.

CORONAVIRUS PANDEMIC

In New York City, about 60% of adult residents and about 51% of all residents have been fully vaccinated against the coronavirus.

“Please get vaccinated because we have a highly effective countermeasure against this Delta variant,” said Dr. Anthony Fauci, chief medical advisor to President Joe Biden.

Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, warns that there could be a spikes in any community where vaccination rates are low.

READ MORE: Moderna: ‘Encouraging’ Data Shows Its COVID Vaccine Remains Protective Against Delta Variant

“Approximately 1,000 counties in the United States have vaccination coverage of less than 30%. These communities, primarily in the southeast and midwest, are our most vulnerable,” she said.

COVID VACCINE

Nationwide, just about one in five 12- to 15-year-olds are fully vaccinated, and with a new school year approaching, now is the time to get eligible kids their shots.

“People say, ‘Well, the children don’t get that sick. They’re not as infectious as others.’ But in fact, this disease has caused more deaths in children than the flu does,” said Dr. Yvonne Maldonado, with Stanford Medicine.

Some New Yorkers are concerned about the variant’s rise in the city.

“Definitely concerned just because we don’t know enough. I am fully vaccinated, but yeah, it is scary to think that we might be going back into a lockdown,” Upper West Side resident Apik Zorian said.

“They’re monitoring it, so fingers crossed. I’m hopeful we don’t have to go backwards in terms of the virus and lockdowns and everything,” Upper West Side resident Jonathan Maas said.

Watch Dave Carlin’s report — 

Earlier this week, the city’s health commissioner, Dr. Dave Chokshi, said the variant is something to keep an eye on, but he put things in perspective.

“But the overall number of cases continues to remain low and has decreased very significantly in recent weeks. My primary concern with respect to the Delta variant is people who are unvaccinated,” he said.

About half of city residents remain unvaccinated, and they are the most vulnerable to this virus.

Health officials are making an urgent plea to get the shot if you haven’t already and to continue wearing a face mask in the meantime.

MORE NEWS: COVID-19 Delta Variant Causing Nations To Rethink Loosening Restrictions, But NYC Confident It Doesn’t Need To

CBS2’s Nick Caloway contributed to this report. Editor’s note: This story was first published on Thursday, July 1.

Dave Carlin