In the first briefing from the White House's Covid-19 team since the variant was identified, coordinator Jeff Zients told reporters Tuesday that the administration believes "the current vaccines provided at least some protection against this variant and that boosters strengthen that protection significantly."

However, he added, "In the event that additional measures are needed, we will be prepared."

"We're working with Pfizer, Moderna, and (Johnson & Johnson) to develop contingency plans for modifications to vaccines or boosters if they're needed. And we will ensure that the (US Food and Drug Administration) and (US Centers for Disease Control and Prevention) review them as fast as possible while maintaining their rigorous scientific protocols," Zients added.