Ronna McDaniel, the GOP chairwoman, took to Twitter late Monday to criticize what she sees as President Biden’s attempt to take credit for his predecessor’s vaccine accomplishments—even after casting doubt about safety during the campaign.

"During the campaign, he [Biden] encouraged Americans not to trust Operation Warp Speed," McDaniel posted.

In September, Biden expressed concern about receiving a vaccine that was approved during the Trump administration. He stressed that he trusted scientists and vaccines but said he did not trust Donald Trump.

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"And at this point, the American people can’t either," he said.

The Washington Post reported at the time that Biden hinted that Trump could be pressuring his agency officials to approve vaccines for an electoral boost.

Vice President-elect Kamala Harris also made headlines and stirred controversy during September and October when she said on multiple occasions that she wouldn’t trust the president’s word on taking the vaccine.

"If the public health professionals, if Dr. (Anthony) Fauci, if the doctors tell us we should take it, I'll be the first in line to take it, absolutely," Harris said during her single debate with Vice President Mike Pence. "But if Donald Trump tells us we should take it, I'm not taking it."

Vivek Murthy, the former U.S. surgeon general and top COVID-19 adviser for the Biden campaign, told STAT News at the time that in most cases both political leadership and scientific leadership speak with one voice, but with Trump, "we’ve seen time and time again that there has been a divergence between the scientists and the political leadership, and the efforts to even influence, in an inaccurate direction, what the scientific guidance is."

Biden and Harris have both been vaccine proponents since their approval and were recently credited when approximately 3 million were administered in one day.

Trump has touted his administration's efforts, arguing that without him, Americans wouldn't receive a vaccine for years.

"I hope everyone remembers when they’re getting the COVID-19 (often referred to as the China Virus) Vaccine, that if I wasn’t President, you wouldn’t be getting that beautiful 'shot' for 5 years, at best, and probably wouldn’t be getting it at all," read a statement from the former president. "I hope everyone remembers!"

McDaniel also said that only 1% of the 1.9 trillion relief bill is earmarked for vaccines.

Sen. John Barrasso, R-Wyo., said Sunday on ABC's "This Week," that "only 9% of the money actually goes to defeating the virus."

"Only 1% of the money goes for vaccines," he said. "This is a Nancy Pelosi pay off to the liberal left."

Fox News' Paul Steinhauser and Peter Aiken contributed to this report