There's a 9% chance of two false negatives in a row, so that could be the case. But why would he develop a fever so late after being first tested positive? His

There's a 9% chance of two false negatives in a row, so that could be the case. But why would he develop a fever so late after being first tested positive? His fever would have been 20 days after first detection of his infection. Also, the article doesn't say whether he had fever initially and it went away and then came back, which is important information.