The head of the National Institutes of Health said Sunday that the new Omicron variant has a “record” number of mutations but claimed the current COVID-19 vaccines will “most likely” be effective against them.

NIH Director Francis Collins acknowledged that there are concerns that the variant is a “sufficiently different virus due to its unprecedented mutations, particularly in the spike protein, the component of the virus that binds to cells.

“We do know that this is a variant that has a lot of mutations – like 50 of them, and more than 30 of those in the spike protein, which is the part of the virus that attaches to your human cells if you get infected,” Collins said on “Fox News Sunday.”

“That is a new record in terms of the number of mutations. It does make you worry, therefore, that it’s a sufficiently different virus, that it might not respond as well to protection from the vaccines, but we don’t know that.”

Still, the top health official said, he was reassured by the vaccines remaining effective against other new strains of the deadly virus.

“It’s clear that in all the previous examples of variants, the vaccines have worked to provide protection, and the boosters have provided especially strong protection against things like [the] Delta [strain],” Collins said. “Given that history, we expect that most likely, the current vaccines will be sufficient to provide protection, and especially the boosters will give that additional layer of protection.”

Collins said it’s too soon to determine whether the Omicron variant causes less severe disease, though a South African doctor treating patients infected with it has described the cases as “unusual but mild.”

“I think the initial cases were mostly young people who tend to have mild infections anyway,” the NIH chief said. “We need more data there before we could say confidently that this is not a severe version of the virus, but we should find that out in the next couple of weeks.”

Experts have said the Omicron variant may be more transmissible based on the surge in cases in South Africa, where the variant was detected by scientists.

The variant has now been also recorded in Britain, Germany, Italy, Denmark, Belgium, Botswana, Israel, Australia and Hong Kong.