New viral variants from India believed to have sparked TTSH cluster

Lawrence Wong says new variant strains have higher attack rates, causing larger clusters than before

New viral variants that originated in India - and are fuelling the devastating second wave there - are believed to have sparked Singapore's largest active cluster at Tan Tock Seng Hospital (TTSH).

Seven cases in three local clusters were found with B16172, a sublineage of a variant from India, said the Ministry of Health's (MOH) director of medical services Kenneth Mak yesterday.

Of these, five are part of the TTSH cluster, which has grown to include 40 TTSH staff, patients and their relatives.

One of the five is the first case in the cluster - the 46-year-old nurse who tested positive for Covid-19 on April 27.


The sixth case with the variant originating in India is an Immigration and Checkpoints Authority officer deployed at Changi Airport Terminal 1.

The remaining case is a cleaner deployed at a community care facility at Tuas South.

"The new variant strains have higher attack rates. They are more infectious, and they are causing larger clusters than before," said Education Minister Lawrence Wong, who co-chairs the multi-ministry task force combating the virus.

"We have tried our best to ring-fence the cases through contact tracing, but we must assume that there are still hidden cases out there in the community."

Viruses mutate all the time, and the B1617 variant was first detected in India in October last year. It has been dubbed the double mutant because it has two major mutations on the spike protein of the coronavirus.

As the cases in India surged, many countries have placed restrictions on travellers from the country.

Yesterday, Prof Mak also said that more cases of worrisome variants circulating around the world have been identified among the 60 new community cases that have emerged in the past week.

MOH has detected eight local cases with the B1351 variant that originated in South Africa, seven local cases with the B117 variant that originated in the United Kingdom, three local cases with the P1 variant that originated in Brazil and one local case with B1525 variant that also originated in the UK.

On how the TTSH cluster spread, Prof Mak said one possibility being studied is issues with the airflow and ventilation in the ward. Other hypotheses are also being examined.

He also said that they have started to study travellers coming into Singapore who have recovered from Covid-19.

"We've not discounted the possibility that some of these recovered travellers might in fact have reinfections and therefore, bring that in and pose a threat to us," he said.

Earlier in the press conference, Health Minister Gan Kim Yong had called for Singaporeans to get vaccinated as well as to rally around front-line healthcare workers, especially those from TTSH and the National Centre for Infectious Diseases.

"A kind word of encouragement or a thoughtful deed goes a long way to boost their morale during these difficult times."

Mr Gan said the healthcare system is being prepared for more Covid-19 cases and the next few weeks will be critical for Singapore.

"The silver lining is that we have successfully brought our cases down before and we can do it again."

This article first appeared in The Straits Times.