Senator and former Vice Presidential nominee Tim Kaine says he and his wife Anne Holton have tested positive for coronavirus antibodies, meaning they may have been infected with the virus.

Kaine says he experienced flu-like symptoms at the end of March but thought it was a “remnant” from a flu diagnosis earlier this year. He and his wife self-isolated at home until mid-April when symptoms disappeared.

Neither Kaine or Holton were tested for coronavirus at the time because of a shortage of tests.

The CDC says more research is needed to determine if antibodies make you immune to future infections or keep you from spreading the virus to others.