Mr Trump has credited his vaccine program, Operation Warp Speed, with saving tens of millions of lives — something he described as "one of the greatest achievements ever" in late August.

But as the president continues to laud his own pandemic response, ABC News reports that a political flashpoint could be developing over the anti-vaccination stance of his hand-picked health secretary, Robert F Kennedy Jr.

USSC Honorary Associate Dr Harry Melkonian was quoted in the article.