The U.S has clarified the message making rounds that it made a call for foreign medical Professionals.
In a statement released on the social media page of the US embassy in Nigeria, the embassy stated that:

The U.S. Mission is aware of a misunderstanding caused by a message that led many to believe the U.S. is recruiting foreign medical professionals to assist the COVID-19 response. This is incorrect. Only medical professionals with a previously approved H or J petition will receive an emergency visa appointment. We are sorry for the misunderstanding.