WASHINGTON- Dr. Anthony Fauci, the top U.S. infectious disease official, said on Sunday he would take the newly approved Johnson & Johnson COVID-19 vaccine, as he encouraged Americans to accept any of the three approved shots.

"All three of them are really quite good, and people should take the one that's most available to them. If you go to a place and you have J&J, and that's the one that's available now, I would take it," Fauci said on NBC's "Meet the Press."

The U.S. government authorized Johnson & Johnson's single-dose COVID-19 vaccine on Saturday, making it the third to be available in the country following ones from Pfizer/BioNTech and Moderna. Both of those vaccines require two doses. 

Shipments to vaccination sites of J&J vaccine are expected to begin Sunday or Monday.

Both the Pfizer and Moderna vaccines showed higher efficacy rates in trials that used two doses versus J&J's single-shot vaccine. However, direct comparison is difficult because the trials had different goals and J&J's was conducted while more contagious new variants of the virus were circulating.

"You now have three highly efficacious vaccines, for sure. There's no doubt about that," Fauci said.

(Reporting by Andy Sullivan; Editing by Lisa Shumaker) ((andy.sullivan@thomsonreuters.com; +1 202 421 5603;))