A medical worker takes a throat swab sample from a fourth-grade student for nucleic acid testing in Licheng Street of Xianyou County in Putian City, East China's Fujian Province, September 12, 2021. (Photo: China News Service)

Experts from the National Health Commission said COVID-19 was already spreading at a Putian primary school for 10 days before the first case was identified. The flare-up now has extended to two other cities - Quanzhou and Xiamen -- involving at least 75 positive infections. 

Epidemic experts believed more cases will be detected in the following days before reaching its peak around September 19 and warned of the risk of an epidemic spill-over to more places. But the experts are optimistic that the flare-up will likely be controlled before the Mid-Autumn Festival (September 21) and the National Day holidays.

The epidemic resurgence in Fujian is severe and complicated as early cases were clustered infections, and more cases from communities, schools and factories are likely to be detected and the risk of epidemic spills over to other places still exists, the visiting experts' team of the National Health Commission said on Monday. 

Since September 10, the infections linking to Putian's epidemic resurgence has soared to 75 in three days, affecting at least two other cities, Quanzhou and Xiamen. There are 67 positive cases from Putian, seven from Quanzhou and one from Xiamen. 

Putian's locally-transmitted epidemic mainly has two chains of transmission - the one relating to Putou Primary School and one relating to Xiesheng shoe-making factory. The total infections from the school increased to at least 15 and at least 10 other infections from the Xiesheng shoe-making factory as of press time.  

Preliminary studies suggest the outbreak may be traced to father of a student at the school who recently returned to Putian from Singapore. The person surnamed Lin tested positive on September 10, 38 days after returning from Singapore on August 4, during which he took nine nucleic acid and serologic tests, which were all negative. 

Lin returned home after finishing his quarantine on August 26 and then his child started new semester at Putou Primary School on September 1. Later the virus may have spread at the school to other students until the first case was detected on September 10. More positive cases among students are likely to be detected. 

Based on an epidemic prediction model, Huang Senzhong, an expert from Nankai University, said the final total infections relating to this wave of resurgence will stay between 100 and 300 in an ideal situation and the outbreak will likely be under control by early October. 

In light of China's previous anti-epidemic experience and epidemiology, the epidemic peak is likely to reach around September 19 and the infection scale combining locally-transmitted and spill-over cases could be within 500, Huang said. 

A Baidu "migration map" showing the most popular travel routes out of Putian between August 26 and September 11 reveals that most people traveled from Putian to nearby cities within the province, including Fuzhou, Quanzhou and Xiamen. Major cities in South China's Guangdong Province, such as Guangzhou and Shenzhen, also saw steady population inflows from Putian.

The Global Times found several other provinces such as Southwest China's Sichuan Province's Chengdu, East China's Shandong and North China's Hebei provinces are now seeking potential close contacts of Fujian's COVID-19 infections.

Global Times