SINGAPORE — Singapore said on Friday that it would ban dining in restaurants and gatherings of more than two people to try to stem a rise in coronavirus cases, becoming the latest Asian nation to reintroduce restrictions after keeping the illness mostly in check for months.
The new measures came after the city-state recorded 34 new cases on Thursday, a small number by global standards, but part of a rise in infections traced to vaccinated workers at Singapore Changi Airport.
The airport outbreak began with an 88-year-old member of the airport cleaning crew who was fully vaccinated but who tested positive for the virus on May 5. Co-workers who then became infected later visited an airport food court, where they transmitted the virus to other customers, officials said.
None of the cases linked to the airport outbreak are believed to have resulted in critical illness or death, according to officials.
In all, 46 cases have been traced to the airport, the largest of about 10 clusters of new infections in the country.
“Because we do not know how far the transmission has occurred into the community, we do have to take further, more stringent restrictions,” said Lawrence Wong, co-chair of Singapore’s coronavirus task force. The measures will be in effect for about one month beginning on Sunday.
According to preliminary testing, many of those infected were working in a zone of the airport that received flights from high-risk countries, including from South Asia. Several have tested positive for the B.1.617 variant first detected in India, which the World Health Organization has said might be more contagious than most versions of the coronavirus.
Singapore health officials said that of 28 airport workers who became infected, 19 were fully vaccinated with either the Pfizer or Moderna vaccines, the only two approved for use in Singapore.
“Unfortunately, this mutant virus, very virulent, broke through the layers of defense,” Transport Minister Ong Ye Kung told a virtual news conference on Friday.
Mr. Ong also said that the rise in cases “very likely” means that a long-delayed air travel bubble with Hong Kong would not begin as scheduled on May 26.
Singapore, a prosperous island hub of 5.7 million people, saw an explosion of infections among migrant workers living in dormitories, but a two-month lockdown and extensive testing and contact tracing contained the outbreak. Although Singapore has kept much of its economy open, its vaccination effort has not moved as quickly as many expected: less than one-quarter of the population has been fully inoculated.
Changi Airport, which served more than 68 million passengers in 2019, is operating at 3 percent of capacity as Singapore has paused nearly all incoming commercial traffic. Employees there work under strict controls, wearing protective gear and submitting to regular coronavirus tests.
Singapore joins Japan, Thailand and other Asian countries that have struggled to contain new outbreaks fueled in part by variants. But Paul Ananth Tambyah, president of the Asia Pacific Society of Clinical Microbiology and Infection, said that the rise in cases was not overly worrying.
“The reason for my optimism is that we now have effective vaccines, better diagnostics, proven treatments and even potential prophylactic agents,” he said. “If these are employed in a targeted approach, it is unlikely that we will end up with the same problems we had last year.”