Media playback is unsupported on your gadget
Mr Pence appeared to be the only individual present not in a facial covering at the Mayo Clinic in Minnesota.
In an erased tweet, the clinic said the vice-president had been informed in advance of its policy needing masks.
Mr Pence leads the White Home coronavirus taskforce.
Media playback is unsupported on your device
The US government’s own coronavirus-prevention guidance is that people should use face coverings “in public settings where other social distancing measures are hard to preserve”.
The Mayo Center itself needs all clients and visitors to its medical centres to use a mask or face covering.
Mr Pence was accompanie