Schrodinger's cough 

The winter cough that afflicts British folk, so called as it is both simultaneously serious enough to be nearly dying and needing antibiotics but simultaneously not bad enough to be COVID and in need of a PCR.

So called after Schrodinger's cat, a thought experiment in which a hypothetical cat may be considered simultaneously both alive and dead as a result of its fate being linked to a random subatomic event that may or may not occur.

"Remember that fella who wanted antibiotics the other day? Schrodinger's cough, couldn't be COVID so couldn't possibly go for a PCR"

Schrodinger's cough by John Whitaker October 13, 2021