(NewsNation Now) — Dr. Anthony Fauci said those who received the one-dose Johnson & Johnson vaccine should’ve been given two shots from the beginning.   

"What the advisers to the FDA felt is that, given the data that they saw, very likely this should have been a two-dose vaccine to begin with," Fauci told ABC’s “This Week” on Sunday.

The Food and Drug Administration vaccine advisory panel on Friday unanimously recommended a second booster shot for all Johnson & Johnson recipients 18 years and older. 

The FDA will use the advisers’ recommendations to decide whether to authorize boosters for both J&J and Moderna. Then, the Centers for Disease Control and Prevention would rule on who should roll up their sleeves.

The J&J booster is recommended at least two months after the initial vaccination, versus six months later for the Pfizer and Moderna vaccines. 

Dr. Anthony Fauci also appeared on Fox News Sunday, saying it is “really unfortunate” that Gov. Greg Abbott has moved to ban vaccine mandates in the state of Texas.

The nation’s leading infectious disease doctor said the Republican governor’s decision to block businesses from requiring inoculations would damage public health since vaccines are the “most effective means” to stop the spread of COVID-19.

Fauci was largely encouraged by the downward trend of coronavirus hospitalizations and deaths across the nation and suggested that vaccinated individuals could have a normal holiday season with others who have received the shot. But he said that those who have not been vaccinated should continue to avoid gatherings and should wear a mask.

He also suggested that those who received a shot of the Johnson & Johnson vaccine would likely have the flexibility to get a booster from either Moderna or Pfizer.