You know it's not.

You can't say that we now have Margaret, clearly three highly efficacious vaccines.

Top US infectious diseases expert Dr Anthony Fauci on Sunday urged Americans to take any of the three approved covid 19 vaccines available to them, including the newly authorized single shot vaccine from Johnson and Johnson.

Both the Pfizer and Moderna vaccines showed higher efficacy rates in trials that used two doses.

However, Fauci and other experts say direct comparison is difficult because the trials had different goals and J and J's was conducted while more contagious new variants of the virus were circulating.

It is expected to get final approval for widespread use on Sunday after the FDA authorized its emergency use, with shipments expected to begin Sunday or Monday.

And while both the Pfizer and Moderna vaccines need to be shipped frozen, J and J's can be shipped and stored at normal refrigerator temperatures.

Daily Infections have declined since their January peak, and some states have begun to loosen restrictions on public gatherings.

However, Fauci, on CBS's Face the Nation, warned that caseloads could rise again if officials move too quickly right now as we're going down and plateau going is not the time to declare victory because we're not victorious yet, particularly with the vary instead of circulating in various parts of the country.

Fauci said he expected 20 million doses of J and J's vaccine to be available by the end of March.