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THREE COVID-19 LOCAL CASES TESTED POSITIVE FOR OMICRON BA.4 AND BA.5 VARIANTS

15 May 2022

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As part of our active surveillance of the COVID-19 situation, the Ministry of Health (MOH) has detected two local COVID-19 cases infected with the BA.4 variant, and one local case infected with the BA.5 variant. These are the first community cases confirmed to be infected with the BA.4 and BA.5 variants. The European Centre for Disease Prevention and Control has recently classified them as Variants of Concern.

2. The presence of BA.4 and BA.5 variants in these three cases was detected via further testing of polymerase chain reaction (PCR) positive samples and confirmed through whole genome sequencing (WGS). All cases were either asymptomatic or had mild symptoms such as fever, cough, runny nose and sore throat; and did not require hospitalisation. They are fully vaccinated, and had earlier received their booster dose.

3. All three cases had self-isolated upon testing positive for COVID-19 and did not have any reported exposure to vulnerable settings.

4. BA.4 and BA.5 were first reported by South Africa in early 2022 and have since become the dominant variants there. Both lineages contain mutations in the spike protein which appear to confer greater immune escape properties and higher transmissibility compared to the BA.1 and BA.2 causing the Omicron wave earlier this year. However, emerging real-world evidence from other countries supports that BA.4 and BA.5 infections will likely give rise to similar clinical outcomes, compared to previous Omicron lineages. According to the WHO, at least 1,000 cases of BA.4 and BA.5 have been reported in at least 16 countries as of 11 May 2022.

5. We will step up local surveillance efforts and continue monitoring the spread of BA.4 and BA.5 in Singapore. While our society is now more resilient against the virus, everyone should to continue to play their part and remain vigilant to mitigate the spread of COVID-19. In particular, persons vulnerable to complications of COVID-19, such as unvaccinated persons, persons above the age of 60, and persons with chronic diseases, should ensure they are up to date with their recommended boosters and exercise caution in settings with many potential contacts.