New Brunswick-based Johnson & Johnson is getting closer to getting FDA approval for distribution of its COVID-19 vaccine.

The FDA says that the single-dose vaccine is safe and effective against the virus and could be seen as a game-changer for some members of the vulnerable population. New Jersey COVID-19 medical advisory Dr. Eddy Bresnitz says that this vaccine could be useful for homeless individuals and those in emergency room situations.

“One dose, less effects, almost comparable efficacy,” Bresnitz says.

Bresnitz says that these are the key factors that set the J&J vaccine apart from the others, along with its 66% efficacy rate.

"It is true that the overall efficacy is a little bit lesser than the Pfizer and Moderna vaccine. But it's the most severe disease and its complications that we’re most concerned about and this meets the standard for that,” he says.

The vaccine is proven to be 85% effective in preventing severe disease and nearly 100% effective in preventing hospitalizations and deaths. The fact that it is a single dose is also getting a closer look with more clinical trials.

"J&J has a second clinical trial and they haven't reported any results from it, and we probably won't see any results from it in one to three months where they are giving a second dose for the vaccine,” says Rutgers Epidemiologist Dr. Stanley H. Weiss.

Bresnitz says that data has shown that the vaccine is less effective in protecting against severe disease in people 65 years old and older.

“I think we need to see more data on that…a longer follow-up for determining whether or not those individuals are protected potentially at a higher level,” he says.

But the question remains: How long will immunity from each vaccine last?

"We don't know. We're so early in all of this, that we're making our best-educated guesses and those have been pretty good,” says Weiss.

It is estimated that about 54,000-180,000 doses of the J&J vaccine could come to New Jersey once it is approved. This is about 2% of the 2-4 million doses that the federal government is expected to go.

New Jersey will not be getting any special priorities to the vaccine, even though the company is based in the Garden State.