Study Suggests Ba.5 Omicron Subvariant Is More Pathogenic
Researchers in Japan say the BA.5 subvariant of the coronavirus Omicron variant may be more pathogenic, or more likely to cause disease.
A team called G2P-Japan led by Professor Sato Kei of the Institute of Medical Science at the University of Tokyo reported their findings in a preprint of an article released online.
The researchers artificially created a virus that has the characteristics of the BA.5 subvariant and another virus that has the characteristics of the BA.2 subvariant.
They then infected cultured cells with each subvariant to examine how much the virus would grow. They found that 24 hours later, virus levels in the BA.5-infected cells were 34-fold higher than in the BA.2-infected cells.
The researchers also say their experiment using hamsters showed that those inoculated with the BA.2 subvariant lost weight only slightly, but others inoculated with the BA.5 subvariant lost about 10 percent of their weight.
They also say the level of lung inflammation observed in the BA.5 infection was significantly higher than that in the BA.2 infection.
The group says that while it is necessary to do more study on symptoms in humans, their experiments indicate the BA.5 is more pathogenic than the BA.2.
Professor Sato says the viral toxicity will not always weaken. He says the virus continues mutating and it is necessary to stay cautious.