Respiratory infections trend within expected range

The number of respiratory infections in China, including cases with the lesser-known but common human metapneumovirus, is within the expected range for winter, with no unusual outbreak patterns reported and the overall level lower than the previous winter, according to global and Chinese health authorities.

In response to heightened international interest over increasing respiratory infections in China, particularly cases of human metapneumovirus, or HMPV, the World Health Organization said in a recent statement that the upward trend falls into the predicated range for winter across the Northern Hemisphere.

It added that Chinese authorities had confirmed to the WHO that its healthcare system is not overwhelmed, and that hospital utilization is lower than at this time last winter.

"There have been no emergency declarations or responses triggered," said the WHO, adding that Chinese officials have been offering knowledge on prevention to the public.

HMPV is a common respiratory virus that spreads all year round but more seriously in late winter and early spring.

"In China, the proportion of HMPV among all acute respiratory pathogens is relatively low, and the infection usually only causes mild symptoms, though the elderly, children and people with weakened immunity or chronic respiratory illnesses are at risk of developing into severe cases," according to an HMPV diagnosis and treatment guideline released by China's National Health Commission in 2023.

The proportion of HMPV infections among all cases testing positive for acute respiratory pathogens has been rising, up from 4.8 percent at the beginning of December to 6.2 percent earlier this month, according to data released on Thursday by the Chinese Center for Disease Control and Prevention.

"From Dec 30 to Jan 5, the positivity rate of HMPV infections has plateaued, and is increasing at a slower pace (compared with past weeks) in northern provinces. The positivity rate among those age 14 and younger has started to decline," said the China CDC.

It added that the majority of infections remained cases involving influenza, which accounted for 35.5 percent for the week ending on Sunday. Cases of rhinovirus, infections by Mycoplasma pneumoniae bacteria, respiratory syncytial virus and COVID-19 have also been reported.

Flu cases are expected to start declining later this month, according to the China CDC.

Kan Biao, head of the China CDC's National Institute for Communicable Disease Control and Prevention, said during a recent news conference that the scale and intensity of respiratory illnesses are lower than last season.

Li Tongzeng, a physician at Capital Medical University's Beijing You'an Hospital's infectious disease department, told media that improved testing technologies for HMPV have contributed to a rise in reported infections in the past two years.

The nation has established a comprehensive surveillance network for acute respiratory illnesses, bolstered by information submitted by a number of sentinel hospitals that test and monitor different pathogens.

The WHO also said that China has a surveillance system covering a variety of respiratory pathogens in place and publishes detailed reports weekly on the China CDC website.