When South Korea first raised concerns of COVID-19 re-infection in April after patients tested positive weeks after recovery, the uncertainty over immunity to the new coronavirus mounted. Fears were later allayed when researchers discovered these results to be 'false positives', and not a case of getting re-infected. 

For months, the world held its breath on the matter, as experts debated over what it takes to achieve 'herd immunity' and how long the immunity would last. 

Concerns rose again last week as the first confirmed case of re-infection was reported from Hong Kong. Shortly after, two European patients - one in Belgium and one in the Netherlands - were also reported to be re-infected with coronavirus. All three were found to have contracted a different strain from their first infection.

Despite cases emerging, infectious disease experts were not surprised and viewed these cases as rare occurrences. The good news is that both the Belgium and Hong Kong patients had mild to no symptoms, suggesting that residual immunity from their first infection had protected them. So unless many more cases surface, there is no real reason for the world to panic.