Comparative replication and immune activation profiles of SARS-CoV-2 and SARS-CoV in human lungs: an ex vivo study with implications for the pathogenesis of COVID-19 

Little is known about how SARS-CoV-2 causes disease; thus, studying this will increase knowledge that will help us to stop the spread of infection and to find a cure. A team of experts from HKUMed studied how the virus infects and multiplies in human lung tissues. The results, published in a leading medical journal, Clinical Infectious Diseases, compared SARS-CoV-2 with SARS-CoV, the coronavirus responsible for the 2003 SARS outbreak, in terms of how they attacked human lung tissue.  

Key takeaways: 

• SARS-CoV-2 and SARS-CoV infected the same types of cells in the lungs. 
  
• SARS-CoV-2 was more capable of infecting lung tissue than SARS-CoV. 
  
• Once infected, SARS-CoV-2 multiplied 3.2 times faster than SARS-CoV in 48 hours, explaining the rapid spread of the virus during the early stages of infection. 
  
• The immune system had a poor response to SARS-CoV-2, which allowed this virus to infect and multiply better. 
  

A poor immune response to SARS-CoV-2 allows this virus to multiply faster in the lungs, the moment it enters the body. This means that an infected person has more opportunity to further spread the virus through respiratory droplets or secretions even before symptoms appear. Good control measures, such as hand washing, social distancing and wearing a mask.