UNION CITY, N.J. (CBSNewYork) — New Jersey now has a third weapon in the fight against COVID-19: Johnson & Johnson’s single-dose vaccine.

Hundreds of seniors in Union City were among the first in the state to receive the shot Friday, CBS2’s Natalie Duddridge reported.

READ MORE: COVID Vaccine On Long Island: Doses Of Johnson & Johnson Vaccine Arrive, Babylon Woman Among First To Receive Shot

Anna Maria Flores said a huge weight was lifted off her shoulders after the vaccine was administered.

“Relief,” Flores said.

She’s one of 400 seniors at the Union Plaza Apartments getting the vaccine. The complex was selected because a large number of seniors with disabilities live there. The one-and-done shot is much more accessible.

Many of the residents Duddridge met had been worrying about how to use a computer to book an appointment, or even how to physically get there. So health officials brought the vaccine to them — right in their own apartment building.

Since the Johnson & Johnson shot only requires one dose, they would be fully vaccinated.

“It’s terrific because you never know what could happen in six weeks or four weeks, or whatever,” said Lourdes Rodriguez, who was also vaccinated.

READ MORE: COVID Vaccine: CBS2’s Dr. Max Gomez Has What You Need To Know About The Johnson & Johnson Shot

There have been questions surrounding the Johnson & Johnson shot’s overall efficacy not being as high as Moderna’s and Pfizer’s.

But the CEO of Johnson & Johnson – which is based in New Jersey – said it has advantages. It’s easier to transport since it doesn’t require a special deep freezer, making it easier to bring to vulnerable communities.

“We designed this in a way with diversity and equity in mind. Over 20% of the patients in our trial were of Hispanic and Latino descent in the United States, over 13% Black, African American” said Alex Gorsky. “These communities have been hit too hard by this disease.”

Gov. Phil Murphy also stressed the sooner people get shots, the likelier it is they stay out of the hospital and stop the spread of COVID variants.

“This vaccine was tested in the teeth of the raging virus, including a significant amount of the trial in South America, Brazil specifically, South Africa,” Murphy said. “One-hundred percent effective against hospitalization and death, thank God, 85% effective against severe illness.”

Murphy said the state will be receiving 70,000 Johnson & Johnson vaccines this week, which works toward his goal of vaccinating 70% of adults by July.

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The governor also said the state is taking baby steps toward reopening, but health officials are still wary of virus mutations.

Natalie Duddridge