No known case here of Covid-19 reinfection, but ministry on lookout

Nobody in Singapore is known to have been infected with Covid-19 a second time, but this is something the authorities are monitoring very closely.

The Health Ministry's director of medical services Kenneth Mak noted, however, that there is still not enough evidence to say with certainty that a person who has recovered from the virus has long-lasting immunity.

Associate Professor Mak, who was speaking at a virtual press conference yesterday, said the ministry continues to keep an eye out for such cases.

A growing number of anecdotal reports around the world of recovered Covid-19 patients who go on to get a second infection have cast doubt on whether a vaccine can give people long-lasting immunity and whether herd immunity against the virus is achievable.

Experts are still unsure if such reports show evidence of vulnerability to reinfection as they could be the result of false positives in the initial test results.

Some studies have also shown that the levels of antibodies against the virus fall sharply in recovered patients a few months after infection.

But other researchers have said antibodies are only part of the equation because patients still have killer T-cells to combat the virus even if their antibody levels have declined.