Geneva: As winter settles in across the Northern Hemisphere, several countries have seen an increase in acute respiratory infections (ARIs).
This trend is typically driven by seasonal epidemics of respiratory pathogens such as seasonal influenza, respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and mycoplasma pneumoniae, says WHO in a report released earlier this week.
The rise in ARI cases aligns with typical seasonal patterns, with influenza-like illness (ILI) and ARI rates surpassing baseline levels in recent weeks.
About the situation
Countries across Europe, Central America, the Caribbean, Western Africa, and many parts of Asia are experiencing heightened influenza activity, with varying levels of RSV and hMPV circulation.
The seasonal influenza virus is the predominant pathogen in many regions, while SARS-CoV-2 activity remains low, though severe COVID-19 cases have been reported, particularly following the summer surge.
In China with data up to 29 December 2024, acute respiratory infections, including those caused by influenza, RSV, and hMPV, have surged especially in northern provinces. However, the increase in cases aligns with seasonal expectations, and the healthcare system has not been overwhelmed.
No emergency responses or declarations have been triggered, and authorities report that hospital utilization is lower than the previous year. There have been no unusual outbreak patterns observed in the country.
Interestingly, there has been growing international attention on the rise of hMPV cases in China, with suggestions of hospitals being overwhelmed. However, the Chinese government maintains that their surveillance systems, including sentinel surveillance for influenza-like illness (ILI) and severe acute respiratory infections (SARI), are well established and functioning effectively.
"Human metapneumovirus #hMPV is NOT a new virus.
First identified in 2001, it has been in the human population for a long time. It is a common virus that circulates in winter and spring. It usually causes respiratory symptoms similar to the common cold."
– @who pic.twitter.com/zojxwNLgH8
— United Nations Geneva (@UNGeneva) January 7, 2025
According to the China CDC, influenza remains the most commonly detected pathogen, particularly affecting individuals of all age groups except children aged 5-14 years, where mycoplasma pneumoniae is most prevalent.
Surveillance data indicates that RSV activity is decreasing in most regions, with the exception of North America, where RSV cases are on the rise. As for hMPV, the virus has been detected in multiple regions during the winter months, though its detection patterns vary, and not all countries conduct routine testing or report on trends for hMPV.
Typically, hMPV infections cause mild upper respiratory symptoms similar to the common cold, although some cases can result in hospitalization for bronchitis or pneumonia.
WHO continues to monitor the situation at both global and regional levels through collaborative surveillance systems. Based on the recent data, it is evident that the increase in respiratory infections is consistent with seasonal trends.
WHO Advices
WHO has issued guidance for public health responses, advising individuals to take preventive measures such as wearing masks in crowded or poorly ventilated spaces, covering coughs and sneezes, and practicing regular hand hygiene. People with mild symptoms should stay home, while those at high risk or experiencing severe symptoms should seek medical care.
Given the current trends, WHO does not recommend any travel or trade restrictions related to the increase in respiratory infections. Instead, countries are encouraged to maintain robust surveillance for respiratory pathogens and to adhere to guidelines for managing seasonal epidemics.
In China, the public has been urged to adopt health measures to prevent the spread of respiratory infections, and the Chinese government has been providing regular updates on the situation.
Despite the uptick in ARIs, the levels are within the expected range for winter, and healthcare systems are equipped to handle the increase in cases without significant strain.
WHO continues to advise the public to stay vigilant and to follow preventive measures to reduce the spread and impact of respiratory diseases during the winter months.