A new outbreak of COVID-19 in the Chinese port city of Tianjin has included at least two cases of the highly infectious Omicron strain. Authorities have responded by rapidly rolling out mass testing and contact tracing of the city’s population of 14 million and imposing restrictions on movement both within Tianjin and in neighbouring areas including Beijing.

According to the Xinhua news agency, 20 Covid infections were reported on Friday evening and Saturday in the city’s Jinnan district. The first two cases—a staff member at a day-care centre and a 10-year-old student at a primary school—were found to be infected with the Omicron strain. The 18 others, identified through contact tracing, were mainly students and their family members from the same places.

In the past month, imported cases of Omicron have been found in five cities—Tianjin, Guangzhou, Changsha, Shenzhen, and Zhejiang—but with the exception of a few confirmed cases in Guangzhou there has been no identified community transmission.

The current outbreak in Tianjin is particularly concerning as a genetic analysis revealed that the Omicron variant may have been spreading for some time. City health official Zhang Ying said that particular virus had spread for at least three generations—that is, at least two rounds of person-to-person infection—and warned that more cases might emerge. The source of the outbreak has not been confirmed.

While it has not been established that all cases involve the Omicron variant, three quarters of the 20 cases were children aged between eight and 13, according to the Global Times. Young people are known to be more vulnerable to the Omicron strain.

As reported on Monday, two Omicron cases have also been identified in Anyang city in Henan province, more than 300 miles from Tianjin. The cases have been traced to a potential source—a university student who returned to Anyang from Tianjin on December 28, raising the possibility that Omicron has been circulating in Tianjin for nearly two weeks.

If the virus has been in Tianjin for that time, it raises concerns that it might have spread to Beijing which is about 120 kilometres away. Beijing is due to host the Winter Olympics starting in early February.

As of Saturday night, Tianjin had quarantined more than 75,000 people, subway lines had been partially closed and many flights cancelled. Residents were encouraged not to travel to other areas of the country except where absolutely necessary.

The response of Chinese authorities to the Omicron cases based on their “zero Covid” strategy is in stark contrast to that of governments around the world, which have allowed and even encouraged Omicron to spread on the unverified and unscientific basis that it is a milder covid strain.

On Sunday, city authorities began testing the entire city with the process due to be completed within 24 hours in four districts by Monday morning and in another 12 districts by Tuesday morning. So far, swabs have been taken from more than 9.6 million people, and testing has been completed for over 3.4 million people.

To date, there have been a total of 31 local confirmed cases and 10 asymptomatic infections all of whom have been isolated and treated in specially designated hospitals.

On Sunday evening, Tianjin authorities issued a notice encouraging all residents to isolate themselves at home. At the same time, the Tianjin Epidemic Prevention and Control Headquarters has completely closed more than 20 of the most severely affected residential communities. Following widespread complaints during the lockdown in the city of Xi’an, those forced to isolate at home in Tianjin have been assured that they will receive necessary supplies.

All tutoring centres, daycare centres and vocational training centres have been closed down while universities and colleges have sealed off their campuses.

Tianjin is regarded as one of China’s top cities. It is one of only four provincial-level municipalities—together with Beijing itself, Shanghai and Chongqing—directly administered by the central government. It is the major port for northern China, including Beijing in particular, and ranks as one of the largest ports in the world measured by throughput.

Tianjin authorities have not yet imposed a city-wide lockdown like that implemented in Xi’an over recent weeks. The lockdown of that city since December 23 has largely suppressed the outbreak with just 15 new symptomatic cases reported yesterday down from 30 on Sunday, and well below the daily highs of between 150 and 200 cases. The total number of infections in the Xi’an outbreak is now over 2,000.

The COVID outbreaks in Tianjin and Xi’an are miniscule compared to the daily infections taking place around the world, particularly in Europe and the United States. The total number of infections in China for the pandemic is just over 100,000 in a country of 1.4 billion people. By comparison, the number of infections daily in Australia, with a population of just 25 million, has climbed rapidly in the last month to more than 100,000.

Since China successfully suppressed the initial COVID-19 outbreak in Wuhan, the outbreaks have all been traced to infections brought in from outside the country. While the outbreaks have been contained, their continuation underscores the fact that the elimination of COVID-19 requires a globally-planned, scientifically-based strategy.

Far from encouraging other governments to follow China’s example, the US and international media treats China as an aberration, paints its public health measures in the blackest light, and regards the criminal “herd immunity” policy elsewhere as “normal.” Yet even then, article after article is compelled to acknowledge that the Chinese government’s policy has broad popular support.

A study by Chinese mathematicians released in November conservatively estimated that if China had adopted the COVID-19 policies pursued in the United States it would be experiencing daily case numbers of well over 600,000 which would result in large numbers of hospitalisations and deaths. As it is, China has registered less than 5,000 Covid deaths—all but two of which occurred in the first months of 2020 during the initial Wuhan outbreak.