People who have already received two shots of the Pfizer COVID-19 vaccine will likely need a third shot or booster shot.

Pfizer's CEO says the booster would be needed in six to 12 months after a person's second dose.

The third shot would be needed to fight off future variants of the virus and to restore antibodies within the vaccine that could start to wear off after time.

Residents who received their shots at the state vaccination megasite at the Meadowlands on Friday said they have no problem with a third shot, while others said they figured out that a third dose would be needed.

"I figure it's going to be like the flu shots where it's recurring probably year to year, so I'm not really surprised by that," said Charles Bivona, of Franklin Lakes.

Pfizer's CEO also said it is very possible the COVID-19 vaccine could become an annual shot.

Meanwhile, Moderna has also been studying the possibility of a booster.

Stanford Medicine began its Pfizer vaccine trial for children under 12 on Wednesday. It was the first day children 2 to 5 years old got their first doses.