Written By: Longjam Dineshwori | Updated : June 24, 2022 12:26 PM IST
The current COVID surge in the UK, the US, India and some European countries, are believed to be majorly driven Omicron sub-variants BA.2, BA.4, and BA.5. Studies have also shown these new variants have the potential to escape vaccine-induced immunity as well as previous infections. Now, a new study has indicated that these Omicron sub-variants may have evolved to target the lungs, suggesting that they are as dangerous the earlier variants, such as Alpha or Delta.
Although the Omicron variant of COVID-19 is highly contagious, it was known to affect the upper airways more than the lungs, unlike Delta. This was thought to be the reason why most Omicron infections tend to be milder, causing common cold-like symptoms.
But researchers from the University of Tokyo warned that the risk of Omicron sub-variants, particularly BA.4 and BA.5, to global health is potentially greater than previously thought, a news agency reported.
The University of Tokyo study suggested that Omicron sub-variants BA.4, BA.5, and BA.2.12.1 may have evolved to cause infection of lung cells, just like the Alpha or Delta variants.
Separate experiments conducted by the varsity's research team suggested that BA.4, BA.5 and BA.2.12.1 replicate more efficiently in human lung cells than BA.2, while BA.4 and BA.5 may cause more severe disease in hamsters.
Dr Stephen Griffin, a virologist at the University of Leeds, also opined that Omicron variant may be mutating to a more dangerous form and going lower down in the lung, as reported by UK media.
Speaking to IANS news agency, Dr. Neha Gupta, Consultant, Infectious Disease, Fortis Memorial Research Institute, Gurugram, also pointed out that COVID-19 patients today are presenting more severe symptoms than during the earlier Omicron wave.
A study from Beth Israel Deaconess Medical Center of Harvard Medical School found 3-fold reductions in antibody responses against the BA.4 and BA.5 sub-variants among fully vaccinated people as well as those who had previous Covid-19 infection, compared with the original coronavirus.
A separate study by scientists at Columbia University revealed that the BA.4 and BA.5 variants were more likely to escape vaccine-elicited antibodies compared with other Omicron sub-variants.
With inputs from agencies
