Fauci: Israeli COVID-19 study misleading on vaccine effectiveness

He added that he would be careful in drawing conclusions about the vaccine’s efficacy against the variant.

"With all due respect to my so-many Israeli friends, I think that that reprint — or preprint, as it were, was about as confusing as you possibly could be," Fauci said. "The only thing that wasn’t confusing about that was that you probably need two doses, the way we’ve been saying, absolutely if you want to get protected and get greater protection, because you saw things shifted when you were one or two weeks beyond the second dose.  So that’s the first point.

"The second point is that I believe the misleading part about it is it made it seem like you were more likely to get the [B.1.]351 if, in fact, you were vaccinated against the mRNA," he continued. "That wasn’t the case.  If you were going to get infected with anything, you would get infected with the more difficult variant, which was 351.  That doesn’t mean you have a greater chance of getting it, because when you went out into the post-vaccination period, you were really quite well protected."

Coronavirus vaccine’s efficacy is often described based on the ability of the inoculation to prevent people from contracting the virus. However, a key factor in evaluating how effective a vaccine is is its ability to prevent serious disease, hospitalization and death.

A real-world study conducted by Clalit Health Services and Tel Aviv University in Israel and released on Saturday showed that the South African variant is more likely to break through the vaccine’s protective effect, even after two doses have been administered and more than a week has passed.

However, the study referred to the ability of the vaccine to prevent from infection, not from serious symptoms.

"What we do know, when these breakthrough infections do occur is they tend to occur with fewer symptoms, less virus — less transmissible virus," added Rochelle Walensky, the director of the Centers for Disease Control during that same White House briefing. "We’re still learning about the transmissibility of this virus in the context of these breakthrough infections.  But I would say: Use your prevention measures when you’re outside the home, and I think you’re okay when you’re in the home."