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Mr Javid, who took on the role in June, has had two vaccinations. He took a lateral flow test after feeling “a bit groggy” on Friday night and is self-isolating.
England is set to remove almost all Covid-19 restrictions on July-19 despite a surge in cases.
Mr Javid has defended the move, despite acknowledging that daily infections could rise above 100,000 at some point in the summer.
"I was feeling a bit groggy last night, so I took a lateral flow test this morning and it's come out positive, so I'm now self-isolating at home with my family until i get the results of a PCR test,” the 51-year-old said in a video posted on Twitter.
"I'm grateful that I've had two jabs of the vaccine and so far my symptoms are very mild."
Mr Javid, who used to be head of the UK’s finance ministry, called on people to “come forward for your vaccine if you haven't already”.