Identical genome sequencing of Covid-19 variant found in domestic helper and engineerLocal | 1 May 2021 8:25 pm
The genome sequencing of the viral samples from the domestic helper living in Tung Chung was identical to that of the Indian engineer living in Jordan, according to a study by the University of Hong Kong.
Both their genome sequencing belonged to that of the B.1.351 variant from South Africa, the university found.
Government pandemic adviser and microbiologist Yuen Kwok-yung said the HKU study showed that the mutations found on the domestic helper’s infection must have spread from the engineer.
Yuen said the mutations, which might become more infectious, had already circulated in the community -- in addition to the Covid-19 strain from Nepal identified during the fourth wave of infections.
He said the spread of the mutations also showed leakage in border control or quarantine measures, or that problems with collecting specimens or testing procedures that led to false negative results.
Meanwhile, Yuen called for field auditing for private laboratories and random retesting of ‘negative’ samples.
He also called on the government to run antibody tests on those who recently left quarantine hotels.
In particular, Yuen singled those who recently stayed in the Ramada hotel in North Point --
where the engineer underwent quarantine upon his return from Dubai, and in the Sai Ying Pun hotel where another domestic helper was found to be with the mutations alongside the family in the next room.
He also warned that the mass Covid-19 testing of some 370,000 domestic helpers could not replace contact-tracing work that locates the origin of the transmission chain.
Another government pandemic adviser and respiratory specialist David Hui Shu-cheong said researchers from the Polytechnic University also drew the same conclusion on the genome sequencing of the domestic helper and the engineer.
Hui said it was likely that the engineer who completed his 21-day hotel quarantine on April 9 had silently spread the mutations to the community.
“He mostly infected his friends in Jordan, before indirectly affecting the foreign domestic helper,” he said.
But he said it was necessary to adjust infection control measures or panic at this stage, adding that upgrading Covid-19 testing was key.
“We should in fact step up the testing of high-risk groups and we will see about that,” he said.
"You need to inspect the epidemiology and the development before you can make adjustments to the infection control measures.”