Photo: VCG

The COVID-19 virus epidemic has reached a moderate transmission level in China with the test positivity rate significantly higher in southern provinces than in northern regions, and people group of 15 to 59 recording highest positive rate, according to data from Chinese Center for Disease Control and Prevention for the week of July 13-19. 

Data released by the CDC on Thursday showed that COVID-19 has overtaken influenza as the leading pathogen among the top three respiratory pathogens detected in respiratory samples collected from fever clinics and outpatient and emergency departments nationwide. 

The COVID-19 test positivity rate stood at 16.3 percent, up 4.3 percentage points from the previous week, while the influenza positivity rate was 12.6 percent, down 0.9 percentage points week on week.

The CDC has advised elderly people and those with underlying health conditions to take preventive measures, such as wearing masks in crowded places or on public transportation. It also encouraged people with weakened immune systems to receive vaccines on respiratory diseases in accordance with recommended guidelines.

Unlike seasonal influenza, which typically peaks during the winter and spring, COVID-19 does not show a strong seasonal pattern and can spread throughout the year. In summer, people also tend to spend more time in air-conditioned indoor spaces with limited ventilation, creating conditions that may facilitate viral transmission. Increased travel during the summer holidays could further raise the risk of person-to-person transmission, Li Tongzeng, chief physician of the Department of Infectious Diseases at Beijing You'an Hospital, told the Global Times.

Li added that population immunity may gradually wane about six to eight months after a previous wave of COVID-19 infections. If new circulating variants emerge and antibodies generated from prior infections or vaccinations provide less protection, another surge in cases could follow.

However, Li downplayed the threat posed by the current wave of COVID-19 infections to the general population. Most infected people now experience symptoms similar to an upper respiratory infection, including fever and sore throat, and typically recover within five to seven days.

From a clinical perspective, the rates of severe illness and death from COVID-19 have not risen correspondingly, suggesting that while the virus continues to mutate, newer variants have not become more virulent but have instead become more transmissible, Li said.

During a press conference on July 16, Chang Zhaorui, an expert from China's CDC said that COVID-19 activity in China began to rebound slightly in late May and entered a low-level phase in mid-June. Recent surveillance data nationwide showed that the COVID-19 positivity rate has risen again, indicating an upward trend in infections, although overall activity remains at a low level.

A monthly report on COVID-19 for June by the CDC showed that 79,000 new cases were registered, including 130 critical and one death due to combined underlying conditions amid the overall rising trend. 

Chang said that the NB.1.8.1 lineage of variants remains the dominant circulating strain in China. Current surveillance has not detected any new variants that could pose additional public health risks.