New COVID-19 cluster in Singapore linked to imported case who was ‘probably reinfected’ in India

SINGAPORE: A new local COVID-19 cluster involving three cases has been linked to an imported case who was probably reinfected in India before arriving in Singapore, the Ministry of Health (MOH) said on Tuesday (Apr 20).

The cluster was identified through epidemiological investigations into Case 62045, a 41-year-old accountant who was confirmed to have COVID-19 on Apr 16.

The woman's husband, identified as Case 62143, was confirmed to have COVID-19 on Apr 18. He is a restaurant manager at two eateries.

The couple are permanent residents, and were reported as community cases. They are the other two cases in the new cluster.

The woman's brother-in-law is an imported COVID-19 case, identified as Case 61536. He has been identified as a household contact of the woman and her husband.

The 43-year-old Indian national is a work pass holder. He arrived from India on Apr 2 and was asymptomatic then, said MOH.

He tested positive for COVID-19 in an on-arrival swab test, and was taken to a hospital.

"He was subsequently assessed to be a recovered case based on his high Ct value which indicated a low viral load, positive serology test result on Apr 4, as well as negative pre-departure test taken on Mar 31," said the ministry.

"He was discharged from the hospital on Apr 6, without the need for further isolation as he was deemed to have been shedding minute fragments of the virus RNA, which were no longer transmissible and infective to others."

Eleven days later, on Apr 17, the man was tested for COVID-19 after being identified as a close contact of Case 62045, his sister-in-law.

His polymerase chain reaction (PCR) test and serology test both came back positive.

"The Ct value of his PCR test taken on Apr 17 was lower than his test done on Apr 2, indicating a higher viral load this time," said MOH.

"His antibody titres are also currently very high, suggesting that he was exposed to a new infection which boosted his antibody levels."

In consultation with an expert panel comprising infectious diseases and microbiology experts, MOH has assessed that he was likely to have been reinfected with COVID-19 recently, said the ministry.

"Our epidemiological investigations indicate that Case 61536 was probably reinfected when he was in India, and had been infectious when he returned to Singapore. He then passed the infection to Cases 62045 and 62143," it added.

MOH said that with the emergence of "new variants of concern" around the world, it will closely monitor for reinfection of recovered COVID-19 cases.

The ministry is reviewing Singapore's border measures for recovered travellers, it said.

"Similar imported cases suspected of reinfection will be isolated and undergo repeat COVID-19 PCR tests to monitor the trend of their viral loads, to ensure that such cases are detected promptly," said the ministry.

Singapore reported 14 new COVID-19 infections on Tuesday, including one dormitory case.

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