Mike Pence chose not to wear a face mask during a tour of a US hospital despite the medical centre’s own rules stating that visitors should wear personal protective equipment.
The US Vice President appeared to be the only person present not seen to be wearing a facial covering during the visit to the Mayo Clinic in Minnesota.
Mr Pence was also the only participant not to wear a mask during a roundtable discussion on Mayo's coronavirus testing and research programmes.
All the other participants did, including Food and Drug Administration chief Stephen Hahn.
Mayo tweeted that it had informed the Vice President of its mask policy prior to his arrival but the post was later removed.
Mr Pence explained his decision by stressing that he has been frequently tested for the virus.
"As vice president of the United States I'm tested for the coronavirus on a regular basis, and everyone who is around me is tested for the coronavirus," Mr Pence said
He added that he is following CDC guidelines, which indicate that the mask is good for preventing the spread of the virus by those who have it.
"And since I don't have the coronavirus, I thought it'd be a good opportunity for me to be here, to be able to speak to these researchers, these incredible healthcare personnel, and look them in the eye and say 'thank you.'"
Mr Pence is not the only White House official who has shown a reluctance for face masks.
When President Donald Trump announced new federal guidelines recommending that Americans wear face coverings when in public, he immediately said he had no intention of following that advice himself, saying, "I'm choosing not to do it."
