BRUSSELS (Reuters) - European Commission Chief Ursula von der Leyen said she was leaving the European Union summit in Brussels, less than an hour after it started, because she had been in contact with someone who tested positive for COVID-19 and would go into quarantine. She said on Twitter that she had tested negative for the virus herself. “I have just been informed that a member of my front office has tested positive to COVID-19 this morning,” she said. “I myself have tested negative. However as a precaution I am immediately leaving the European Council to go into self-isolation.”