US officials had predicted that Omicron would be the variant to end the pandemic. However, varying degrees of pandemic lockdown measures are still being carried out in recent weeks, while the new variant in the Omicron family–BA.2 has continued to spread to more than 110 countries based on data from outbreak.info.
To differentiate them better, BA.1 is used as a name to describe the original Omicron.
What is the pathogenicity and transmissibility of BA.2, and how do Covid vaccines and natural immunity hold up against this subvariant? To get clear answers, we turned to Dr. Yuhong Dong, expert in infectious diseases and antiviral drug development.
Where Is BA.2?
Covid cases began to decline early February, and rise again slightly in the week of March 14. These infection waves took place largely in Asia, Europe, and the Pacific. In Europe, there were no large spikes, but increases mainly in France, United Kingdom, and Italy. The largest outbreaks were in China, Hong Kong, South Korea, and New Zealand—these places saw increases in infections and deaths, and the cases were largely of Omicron subvariant BA.2.
In the United States, the CDC stated this week that the majority of Covid cases are now due to the Omicron BA.2 subvariant, which has in recent weeks displaced other variants of the virus.
BA.2 is significantly different from Omicron subvariant BA.1, so much so that Japanese virologists recommended it be treated as a new variant of concern (VOC) entirely.
There are three major differences between these two subvariants BA.1 and BA.2, Dr. Dong explained, regarding the traceability of the subvariant, the transmissibility, and the protections offered by natural immunity and vaccines.
“The New England Journal of Medicine published a study from Harvard University (chart here) which showed that BA.2 has eight new mutations in the spike protein compared to BA.1,” Dr. Dong said. “The mutations in BA.2 are what make it difficult to detect, and that is why it’s referred to as the ‘stealth variant.’”
BY HEALTH 1+1 AND DR. YUHONG DONG
