As Covid-19 wanes, seasonal influenza cases are surging in China
- Outbreaks have prompted some schools to suspend classes, while authorities have issued health alerts
- Rising cases attributed to low immunity and more movement of people after pandemic controls scrapped
The number of flu outbreaks almost tripled in the last two weeks of February, with 112 recorded nationwide in the week ending February 19, according to data from the China National Influenza Centre. In China, outbreaks involving at least 10 people must be reported to health authorities.
Nearly all of the samples that tested positive that week – 99 per cent of 786 samples – were infected with influenza A, a common flu virus that causes symptoms such as fever, aches, headaches and diarrhoea.
Health authorities attributed the rise in influenza A cases to factors including low immunity and more movement of people after Covid-19 restrictions were scrapped in December.
In the east, Zhejiang authorities said influenza A had not been prevalent during the coronavirus pandemic.
“The [flu] vaccination rate has been low in the past three years and the population is generally susceptible,” the Zhejiang Provincial Centre for Disease Control and Prevention said in a statement on Tuesday.
“With the adjustment of Covid-19 control measures, crowd mobility and gatherings increased and it is easier for the virus to spread.”
It noted that winter and spring were usually the influenza seasons.
A number of schools across China have suspended classes or temporarily switched to online learning in response to flu outbreaks.
Meanwhile, supplies of Tamiflu – an antiviral used to treat seasonal flu – are said to be running low at pharmacies, according to media reports.
The outbreaks have prompted health departments to issue alerts and advice to the public to help stop the spread of the virus.
“Seasonal influenza is on the rise, while Covid-19 infections are sporadic and no new clusters have been detected,” Beijing’s Centre for Disease Control and Prevention said in a statement on Monday.
It said the city had seen a 91 per cent increase in cases with flu-like symptoms in the week ending February 19 from the previous week. Some 23 per cent had tested positive for influenza – most of them with influenza A – but the Beijing CDC did not give the number of cases.
The same week, 32 Covid-19 infections were recorded – continuing a downward trend following the peak in December.
Beijing CDC director Zhang Daitao said seasonal influenza was on the rise in the city, with a 78 per cent increase in cases last week compared to the same period in 2019.
“However, the current level is lower than the peak level of influenza in December in the 2018-2019 flu season,” Zhang told official newspaper Beijing Daily on Monday.
“Influenza usually declines after a peak in December and will fluctuate until the end of spring.”
He told the paper that this year’s situation was unusual since the flu seasons had been less intense in the past three years, and a low infection rate meant lowered immunity among the population.
