Influenza on the rise in multiple regions across China, dominated by H1N1 virus
Published: Feb 28, 2023 11:25 PM
Influenza Photo: VCG

Photo: VCG

The spread of influenza has continued to show an upward trend in multiple provinces across China with outbreaks of influenza A (H1N1) virus being reported at many schools in several areas.

Statistics from the Chinese National Influenza Center (CNIC) show that the positive rate of influenza virus continued to rise in both southern and northern provinces during the seventh week of 2023, which is consistent with the usual peak of influenza in the winter and spring.

According to the CNIC's weekly report on influenza released on February 23, the influenza A (H1N1) virus accounted for 71 percent of the total samples of the influenza virus, making it the most prevalent strain.

The Zhejiang Provincial Center for Disease Control and Prevention (Zhejiang CDC) announced on its official WeChat account on Tuesday that influenza outbreaks have occurred at schools in multiple cities across the province with H1N1 being the predominant virus.

The Zhejiang CDC noted that as H1N1 has not been prevalent in the province for nearly three years, the local population is generally susceptible to the virus due to low vaccination rates. Since China downgraded its COVID-19 management on January 8, the increased flow of people and gatherings have also made it easier for the virus to spread, according to the Zhejiang CDC.

Moreover, the Zhejiang CDC stated that during the transition from winter to spring, when influenza is prevalent, the risk of cluster outbreaks in crowded areas persists.

The most recent monitoring data from Beijing indicate a clear increase in the intensity of seasonal influenza epidemic activity, with the number of influenza-like cases growing by 78 percent last week compared to the same period in 2019.

The Beijing Center for Disease Prevention and Control (Beijing CDC) released statistics on Monday indicating that among the prevailing influenza viruses, influenza A has overwhelmingly become the dominant virus, with influenza A (H1N1) accounting for 64 percent and influenza A (H3N2) accounting for 35 percent. Influenza B, on the other hand, only accounts for 1 percent.

Zhang Daitao, Director of the Institute for Infectious and Endemic Disease Control at Beijing CDC, explained that the prevalence of influenza typically peaks in December and then declines, with small fluctuations before the epidemic ends in the following spring.

However, this year is unique as the intensity of the influenza epidemic and infection rates have remained low for the past three years, resulting in a decreased immune level among the population, said Zhang.

Zhang added that with the beginning of the new semester for college, middle, and primary school students in the city, the flow of personnel has increased, gatherings have become more frequent, and influenza activity has shown an obvious rise in intensity.

The Shandong Center for Disease Control and Prevention reports that the influenza epidemic trend in Shandong is similar to that of previous years, with H1N1 remaining the dominant influenza A type, accompanied by a smaller proportion of H3N2 virus type.

Wang Xin, a doctor in the Respiratory and Critical Care Medicine Department at Jinan Central Hospital in Jinan, Shandong, cautioned that while healthy individuals who contract the flu can develop antibodies and recover within a week or two, people with weakened immune systems may develop severe illnesses.

Zhang also emphasized that high-risk groups, including children under the age of 5, elderly individuals, and those suffering from chronic diseases or weakened immune systems, should closely monitor their physical condition if they contract the flu and seek medical attention if the disease worsens progressively.

Global Times