South Korea has today reported no domestic coronavirus cases for the first time since February.
Only four new cases were identified across the country, all of them imported from the Americas or elsewhere in Asia.
South Korea has been widely praised for its mass testing and contact-tracing strategy, which other countries have sought to emulate.
Meanwhile in Vietnam, which also took early action to restrict travel and quarantined tens of thousands of people, the government says it has contained the outbreak after just 270 cases and no reported deaths.
Hong Kong, a city of seven million where there have been just four virus deaths, reported no new cases for the fifth straight day on Thursday.
This graph shows the daily number of coronavirus cases in South Korea, which has slowed to a trickle after the country rolled out mass testing and contact-tracing strategies
The handful of new patients in South Korea take the tally from 10,761 to 10,765, an increase of only 0.04 per cent.
The last time that no domestic cases were reported was on February 18, the Korean Centers for Disease Control and Prevention said.
South Korea was one of the early virus hotspots after a cluster of cases linked to a controversial religious sect, but the epidemic has since lost pace.
Even now, more than 48 per cent of South Korea’s total cases are linked to the Shincheonji Church of Jesus.
Korea reported only one new death in the last 24 hours, bringing the total to 247 – fewer than some European countries have been reporting each day.
Of the four imported cases, one came from China, one from elsewhere in Asia and two from the Americas. Three out of four were Korean nationals.
Authorities have also found no signs of contagion during the April 15 general election, after voters were required to wear masks and gloves.
‘Twenty-nine million voters participated in the April 15 parliamentary election… Not one case related to the election has been reported during the 14 days of incubation period,’ said public health chief Yoon Tae-ho.
President Moon Jae-in’s party won the election in a landslide after widespread praise for the government’s handling of the outbreak.
Nurses wearing white protective suits along with masks and face shields line up to enter a treatment ward at the Dongsan Hospital in Daegu
A voter receives plastic gloves from a staff member at a polling station in Seoul on April 15, during an election which does not appear to have caused a spread of virus cases
Seoul started its testing programme when the numbers were still small, telling companies to develop testing kits as early as January 27.
The first diagnostic kit was approved on February 4, and nearly 100 laboratories are now equipped to carry out tests.
When cases started mounting around the Shincheonji church, officials said they would test every member of the sect.
The city of Daegu announced that nearly all the 10,000 worshippers had been tested by March 10.
Similarly, Vietnam increased its number of testing laboratories from three to 112 – allowing it to carry out 213,743 tests. The country has confirmed only 270 cases and no deaths.
Todd Pollack, a Hanoi-based infectious diseases specialist at Harvard Medical School, said less than 10 per cent of Vietnam’s confirmed patients were over 60 – an advantage against a disease which is most menacing to older people.
Vietnam suspended flights from Wuhan as early as January 23 and closed its 870-mile border with China to all but essential travel a week later.
Tens of thousands of people were quarantined, many of them expats returning home to escape the outbreaks in Europe and the United States.
Medical officials tested suspected cases several times, gradually discharging people from quarantine after they negative several times.
Vietnam has also limited the coronavirus outbreak after introducing mass testing (pictured here, people wait to be tested near the Bach Mai hospital in Hanoi last month)
By mid-March, Vietnam made the wearing of masks in public places mandatory nationwide, well ahead of most other countries.
Kidong Park, the World Health Organization’s representative in Vietnam, said there was no indication of any outbreaks beyond what the government has reported.
Guy Thwaites, director of the Oxford University Clinical Research Unit in Ho Chi Minh City, also said the government’s figures were in line with what his laboratory had seen.
‘If there was ongoing and unreported or unappreciated community transmission, we would have seen the patients in our hospital. We have not,’ he said.
One funeral home manager said requests for funerals had actually gone down during the country’s lockdown because of the reduction in traffic accidents.
South Korea was also a pioneer of contact tracing, using phone location data and smartphone apps to identify clusters of cases.
Mandatory testing and quarantines now apply to nearly all arrivals from overseas, including citizens.
South Korea installed testing facilities this month at Seoul’s Incheon International Airport to screen anyone who arrives with symptoms.
People keep their distance as they prepare for an examination set by the General Insurance Association of Korea in Seoul last weekend
All arrivals must download a government app that tracks their location and requires users to report any symptoms.
Everyone must self-isolate for two weeks if they do report symptoms, regardless of nationality or whether they tested negative.
After the two-week period, the app shows a message saying users are free to delete it from their phones.
In its latest research, a clinical expert panel has found that recovered patients who were feared to have tested positive a second time were in fact false positives.
The country has reported 292 such cases, but the panel said the patients had not been reinfected with the virus.
The false positives were caused by the technical limits of PCR testing, the head of the committee said.
The World Health Organisation has warned that it is not yet clear whether everyone becomes immune to the virus after catching it once, or for how long.
Many countries hope that immunity tests will allow life to return to normal for those who are no longer susceptible, but the tests are not yet fully reliable.