A Covid patient battled the same infection for nearly 18 months, in what is believed to be the world’s longest known continuous case. 

Scientists say the unidentified British patient — who eventually died — was severely immunocompromised.

Medics did not reveal what condition the patient had, how old they were, or whether they were vaccinated. 

But they studied nine different patients with weakened immune systems because of organ transplants, HIV and cancer.