We refer to the report by journalist Natalie Tan, "Covid-19 scare, quarantine for family of 12 after maid's early SHN discharge" (June 1).
To allay employers' concerns, we would like to set out the protocols and processes involved.
People who have recovered from Covid-19 can continue to shed non-infectious viral fragments for several months after the initial infection.
Their polymerase chain reaction (PCR) tests may give a positive result, but they are not infectious.
Hence, inbound travellers found to have Covid-19 antibodies after recovering from a past infection, based on tests performed after arrival in Singapore, were previously exempted from serving stay-home notice (SHN).
However, given the emergence of variants globally and the risks of reinfection, we have since ceased such exemptions.
In addition, as a precautionary move, between April 29 and May 7, we called back 700 migrant domestic workers (MDWs) who had recently entered Singapore for retesting, in order to rule out the possibility of reinfection.
None was found to have been reinfected or infectious.
This includes 127 MDWs who had a positive PCR test result, but through further tests, were later ascertained to be shedding dead viral fragments from an earlier infection.
In the case of the family in Ms Tan's report, as there was strong suspicion of reinfection, the assessment took more time.
As a precaution and in line with our usual processes, we triggered public health action; for example, close contacts were issued quarantine orders.
Although we release close contacts from quarantine once such cases are assessed not to be a reinfection, in the case of the family, the final assessment took longer and was made only after completion of their quarantine period.
We seek the understanding of employers, while we do our best to improve our processes to keep Singapore safe.
Derrick Heng (Dr)
Deputy Director of Medical Services, Public Health Group
Ministry of Health