Singapore sequencing reveals Delta variant crowds out others

[SINGAPORE] Covid-19 sequencing in Singapore has revealed the emergence of the Delta variant as the country's major local virus strain, underscoring the highly infectious nature of the mutation that has proliferated globally since its first detection in India.

Of these cases as of May 31, 449 have been found to be caused by variants of concern, among which 428 were infections of the Delta strain, said the country's health ministry. The next largest group was nine cases linked to the Beta mutation that first emerged in South Africa.

The "current understanding" is that some variants, including the delta mutation, "are more transmissible," a spokesperson for Singapore's health ministry said on Tuesday in a response to questions from Bloomberg News.

"Studies are ongoing to get a more complete understanding of these variants and we will adjust our strategies as more information is made available."

Singapore is one of the only places in the world to sequence all its Covid-19 cases and its data provides the most thorough glimpse yet of how the Delta variant, also known as B.1.617.2, spreads more rapidly. The strain has been identified in more than 60 countries over the past six months since its discovery in India, and concerns are growing that it may extend the pandemic in some places.

A spike in infections in the UK, fuelled by the variant, has prompted Britain to reconsider plans for a total reopening later this month, despite a large vaccine uptake among its population.

Delta has also been linked to unusual symptoms like hearing loss and blood clots leading to gangrene, suggesting its impact may be more severe than other strains. In England and Scotland, early evidence suggests it carries a higher risk of hospitalisation.

Singapore reacted aggressively to the flareup linked to the variant by barring visitors from India in April and extending quarantines at government-designated facilities. It has also limited gatherings to two people, moved school lessons online and barred dining-in last month to slow spread.

The country's authorities only found four locally transmitted coronavirus infections on Tuesday, extending a streak of low daily counts since the start of the week. Yet only one of the four cases was linked to earlier infections while three were untraceable, showing the difficulty faced in completely eradicating the recent outbreak.

The decline in cases comes ahead of a possible easing of restrictions after June 13. Meanwhile, the pace of Singapore's immunisation drive has been hampered by limited vaccine supplies, with the government stretching out the interval between doses to six to eight weeks in order to cover more people with a first shot.

BLOOMBERG