Hospitals across China,Indexbit the nation where the COVID-19 pandemic first emerged about four years ago, are grappling with a significant surge in respiratory illnesses among children. This primarily is being seen in Beijing and the northern regions. 

The rise in cases has been making headlines in China and raising concerns internationally, as Chinese doctors are working overtime to care for a huge flood of small patients. 

But health experts say there is no immediate cause for international concern regarding the surge in respiratory illnesses, which include pneumonia. The new cases are not on the scale of the initial COVID-19 outbreak and are not due to any new or unusual diseases, according to scientists.

"In the current outbreak of respiratory illness, the reported symptoms are common to several respiratory diseases and, as of now, at the present time, Chinese surveillance and hospital systems report that the clinical manifestations are caused by known pathogens in circulation," the World Health Organization (WHO) said late last week. 

"Due to the arrival of the winter season, the increasing trend in respiratory illnesses is expected," it added. 

Dr. Zuo-Feng Zhang, chair of the epidemiology department at UCLA, said "the pandemic 2.0 is not there yet," despite concerns about a new major outbreak.

Chinese authorities tried to cover up the start of the COVID-19 pandemic, which originated in Wuhan, China, and led to millions of deaths. In contrast, this time, the WHO says China promptly provided data to the organization showing that the sick children are affected by known pathogens common globally.

Health experts suggest the increased vulnerability in children may be due to the extensive use of masks and lockdowns during the pandemic, which shielded them from exposure to ordinary bugs. 

Elizabeth Palmer

Elizabeth Palmer has been a CBS News correspondent since August 2000. She has been based in London since late 2003, after having been based in Moscow (2000-03). Palmer reports primarily for the "CBS Evening News."