The Chinese Health Ministry said the rise in cases was linked to an overlap of known pathogens and not any novel viruses as the country braced for its first winter after lifting the Covid-19 restrictions.
There has been a rise in cases linked to viruses such as influenza, rhinoviruses, the respiratory syncytial virus, or RSV, the adenovirus, as well as bacteria such as mycoplasma pneumoniae, the ministry said in a statement.
According to Chinese health authorities, the outbreak could be linked to mycoplasma pneumoniae, also known as “walking pneumonia”, a common bacterial infection typically affecting children that has been circulating since May.
Symptoms of walking pneumonia include:
Lingering cough that can last for weeks or months
This map shows where cases have been reported across the world:
This week, the World Health Organisation (WHO) issued a formal request for disease data on respiratory illnesses and reported clusters of pneumonia in children following the increasing number of cases in China.
Meanwhile in the Netherlands, the number of children aged 5 to 14 years with pneumonia increased to 130 per 100,000 children in the week leading up to 26 November, the Netherlands Institute for Health Services Research (NIVEL) reported. At its peak last year, there were 58 per 100,000 children.
GPs have also seen more pneumonia cases in the group of young people between 15 and 24 years old than in previous years. In week 47 this number increased further to 38 per 100,000.
It is not known whether the uptick in China is connected to the rise of cases in the Netherlands.
Denmark’s Statens Serum Institut (SSI) also reported an increasing number of Danes have tested positive for pneumonia as cases have risen more than three-fold in five weeks from 168 cases to 541.
Senior researcher at SSI, Hanne-Dorthe Emborg, said: “In the past five weeks, the number of new cases has increased significantly, and we are now seeing significantly more cases than usual, and that there is widespread infection throughout the country”.
Speaking about the cases in China, Maria Van Kerkhove, acting director of the WHO’s department of epidemic and pandemic preparedness and prevention, said: “We asked about comparisons prior to the pandemic. And the waves that they’re seeing now, the peak is not as high as what they saw in 2018-2019.
“This is not an indication of a novel pathogen. This is expected. This is what most countries dealt with a year or two ago.”