Singapore will ban entry to all non-residents travelling from India from Friday night, as it faces a new infection cluster among its largely South Asian migrant worker community that has raised fears of reinfection among recovered coronavirus patients. From 11.59pm on Friday, all long-term pass holders and short-term visitors with recent travel history to India within the last 14 days cannot enter or transit through Singapore , including those who have obtained prior approval, authorities said on Thursday. Hong Kong-Singapore travel bubble announcement delayed A multi-ministry taskforce that manages the coronavirus pandemic also revealed that scientific evidence from recovered patients who had caught Covid-19 almost a year ago showed it was possible for antibody levels to decrease. “Immunity in recovered persons can wane and caution is required around the infection risks in recovered persons,” it said in a press release. These findings were released after an announcement on Singapore’s long-awaited travel bubble with Hong Kong did not take place as expected on Thursday. Sources said Singapore had sought to push back the announcement to next week and that the quarantine-free arrangement would start in late May. About one in three of Singapore’s 1 million low-wage migrant workers live in mega-dormitories and factory-converted complexes, and they bore the brunt of the city state’s infections last year. These workers primarily hail from South Asian countries and mainland China, working in the construction, marine shipyard and process sectors. Since November, the number of infections from dormitories has dwindled significantly. But this week, 19 migrant workers at the Westlite Woodlands Dormitory tested positive for Covid-19. One of the cases was a 35-year-old Bangladeshi worker, who showed a positive result during a routine test on April 19, six days after he was fully vaccinated. His roommate also tested positive, as did 17 others in the same dorm who had previously recovered from the virus. Officials have assembled an expert panel of infectious diseases and microbiology experts to assess if these are new infections or if the workers are shedding viral fragments from their earlier infections. Singapore’s migrant workers still segregated, even as Covid-19 abates Meanwhile, authorities are also monitoring how long vaccinations can remain effective and if it is necessary to give the population booster shots. Dr Kenneth Mak, the director of medical services at the Ministry of Health, said Singapore believed the vaccinations could last for 15 to 18 months, and beyond that, it was “a relatively uncertain situation” but authorities were monitoring the immunity levels in those who had been vaccinated. Booster shots may be given if those started declining. Mak said the government was also preparing for the possibility that current vaccines may not be as effective against future Covid-19 variants. Manufacturers were studying this and hoped to produce improved versions of the vaccines, he said. “When such a product is available, we may plan to make that available as booster doses [among those] that have previously been vaccinated,” he said. The taskforce said there was no evidence the recent Westlite dorm cases were linked to a new coronavirus variant, first identified in India, that is potentially more infectious and has sparked a massive outbreak there, leaving hospitals reeling from a lack of staff and oxygen supplies. But many of the incoming arrivals from India were workers in the construction, marine and process sectors, the taskforce said. Even though they would have completed their quarantine obligations before starting work, “there is still a risk that a leak may happen, and cause another wave of infection in the dormitories”. “It is also a concern that recovered workers are susceptible to being re-infected,” the taskforce said. As part of the tightened border measures, incoming travellers to Singapore from India who were still serving their 14-day quarantine in designated facilities as of Thursday night would need to extend their quarantine in these facilities for seven days. Previously, they had the option of doing the additional week at their place of residence. ON HEIGHTENED ALERT Health minister Gan Kim Yong, who co-chairs the multi-ministry Covid-19 taskforce, said there had been a worrying increase in local cases in recent days, and the city state was on “heightened alert” given the resurgence in infections globally and the emergence of variant virus strains. Compared to the nine locally-transmitted cases clocked for the whole of March, Singapore has so far recorded 16 of such infections in April. But the country had in the past months recorded 342 imported infections with potentially more infectious or more deadly mutant strains, including the B117 variant from Britain, South African variants, as well as the B1617 “double mutant” variant from India and Brazil’s P1 strain. Mak, the director of medical services, said that as of Tuesday, authorities had detected seven local cases of the B117 variant, and one local case of the South African B1351 mutant strain. He noted that most of the mutant strains were found in travellers entering Singapore, and that they were picked up during the isolation period. Because of this, they did not mix freely with the community, and there was no further local spread. Grim milestone: India reports global record of 314,835 new virus cases Education minister Lawrence Wong, the co-head of the virus task force, also spoke about the travel bubble with Hong Kong. He said the situation was “fluid” and the travel bubble could only launch “when conditions are suitable and appropriate, when they are safe”. Even if the bubble had already started, a rise in cases in either city would result in the bubble being suspended until the infections were brought under control, Wong said. “So that’s our overall approach, and that’s certainly the approach that Hong Kong takes as well,” he said. “And therefore, at an appropriate juncture, both sides will announce the resumption of the travel bubble.” ADDITIONAL PRECAUTIONS Meanwhile, Singapore will also ramp up testing and quarantine measures for its migrant workers, who live in close proximity to each other in their accommodation and whose interactions with the wider community have been restricted since last year’s outbreak. They are mostly only allowed to travel from their dormitories to their work sites, with some permitted to visit recreational centres. From next Thursday, migrant workers who first tested positive for Covid-19 more than 270 days ago will be required to go for routine testing. They had previously been exempted. If they are found to be close contacts of the infected cases, they will be quarantined. For new arrivals to the migrant worker community, those from higher-risk regions and with a positive serology result would be quarantined at a government facility before being tested again.