Celtic confirmed on Monday that manager Neil Lennon and 13 senior players are self-isolating, but the club are still defending the decision to hold a training camp in Dubai.
Defender Christopher Jullien tested positive for COVID-19 after the team returned to Scotland ahead of Monday's Premiership clash with Hibernian.
Although all other squad and staff members returned negative tests, Lennon, assistant John Kennedy and 13 first-team players are self-isolating after being deemed close contacts.
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The reigning champions remain insistent they followed "rigorous" COVID-secure protocols and that the threat of contracting the virus would have been similarly high had they stayed in Scotland.