"Two of the 20 team members exposed to the confirmed MERS patient are showing symptoms," said Geo Morales, spokesman for the Orlando hospital where one infected patient was treated.
"One of the two has been admitted to the hospital but is in stable condition. The other was treated and discharged and is following precautions at home. All 20 team members have been tested and we are expecting those results within the next day or two," the spokesman added.
The second infected US patient was confirmed as such May 10. The man, 44, is a health care worker who resides and works in Saudi Arabia, who traveled by plane May 1 from Jeddah to London, England, then to Boston, Atlanta, and Orlando, officials from the Centers for Disease Control and Prevention told reporters.
The United States announced its first case earlier this month, a health care worker who had traveled to Riyadh at the end of April.
MERS causes fever, cough and shortness of breath, and can be lethal particularly among older people and those with pre-existing health problems.
Some 30 percent of the several hundred people infected with it have died, according to the US Centers for Disease Control and Prevention.
The virus first emerged in Saudi Arabia in 2012 and recent research has suggested it may originate in camels.
The vast majority of cases have been in Saudi Arabia, but MERS has also been found in 16 other countries. Most cases involved people who had recently traveled to Saudi Arabia.