Your high school learnings would have taught you that when you get exposed to a virus that you've previously come in contact with, your body produces antibodies to fight it off before it develops.
However, there's a catch. Speaking to Cosmopolitan UK, Richard Pebody, Public health England's Head of Influenza, explains that viruses can mutate and there may potentially be two different strains of COVID-19 moving around in the community – that theory goes some way to explaining why the Japanese woman may have contracted it twice.
"The viruses that cause flu can change every year, so even if you’ve had flu recently it’s recommended that you get a vaccination that matches the new viruses that might circulate each year," he said.
"Because flu is caused by several viruses, the immunity you naturally develop after infection will only protect you against that one strain – so you could also go on to catch another strain."
However, health authorities are yet to confirm whether the coronavirus has developed into more than one strain.
"There is no evidence that the virus has been changing,” the WHO says.
Considering WHO is a trusted organisation, we'd say it's fairly unlikely you can catch it twice.