Of over 3,000 people entering Hanoi's Noi Bai Airport and scanned by city authorities, over 2,000 have had their swab samples taken to test for Covid-19. Of about 1,000 confirmed results, four have tested positive, Hanoi People's Committee Chairman Chung said Wednesday at a meeting with the National Steering Committee on the Prevention and Control of Covid-19.

Based on the aforementioned ratios, it can be assumed that there are at least dozens of other Covid-19 positive cases that have yet to be detected and are "roaming the streets," he said. This, in turn, means that it is possible more Covid-19 positive cases would show up in the city from multiple sources in the coming days, he added.

Covid-19 infection cases in Hanoi are thought to originate from four major sources: from cross-infection at the Bach Mai Hospital, a Covid-19 outbreak area that has seen two nurses and a former patient being infected; people entering Vietnam from outside the country; infected people yet to be detected; and medical workers.

The chances of community spread in Hanoi are high, and the window of opportunities to eliminate these chances are getting slimmer, Chung said, adding that a major driving factor was the fact that many still neglect wearing masks in public places.

"I still see a lot of people not wearing masks out on the streets and people still gathering in large crowds," he said, stressing that the best method to prevent infection was to stay at home.

In the next two weeks until April 5, he said, people should refrain themselves from leaving their houses. If one does, one must wear a mask and stay two-three meters away from another, he said.

Hanoi has directed local leaders to ensure that "unimportant businesses" like karaoke parlors, bars, night clubs and cinemas are shut down until April 5 to limit large gatherings as part of the effort to prevent the spread of Covid-19.

Shops selling necessities like food, medicine and fuel can stay open, however.

People have also been advised against using public transportation.

The capital has recorded 52 Covid-19 cases out of Vietnam’s total of 148. Of this total, many of the 131 active cases, currently in hospitals, are Vietnamese and foreigners arriving from Europe and the U.S. The previous 17 people have been discharged.

The Covid-19 pandemic has killed over 21,200 people globally, having spread to 198 countries and territories so far.