New Omicron Subvariant Is More Infectious, More Puzzling COVID Strain
By Staff, Agencies
The number of infections caused by the BA.2 subvariant of the BA.1 omicron coronavirus has surged in the past two weeks, and now accounts for 11 percent of cases among travelers entering the “Israeli” entity. The figure jumped from 7 percent following the entry of a group of Nepalese workers infected with the new subvariant into the entity.
According to the “Israeli” entity’s so-called Health Ministry, 350 infections with the BA.2 subvariant have been verified. “At present we know that the subvariant is more infectious, but does not cause more severe illness than the BA.1 variant,” a ministry spokesman said.
COVID-19 chief Prof. Salman Zarka said Monday that the entity’s
Health Ministry is keeping a close eye on the new BA.2 subvariant, “which according to data from Europe has the potential to be more infectious than omicron, and in some European countries has slowed down the decline in the omicron wave, while in others, such as Denmark, it has sparked a new wave.
“There is almost no delta morbidity and most of the current morbidity is from the omicron BA.1 variant and the BA.2 subvariant. We are still in the midst of a wave with very high [infectiousness]," Zarka said, "a wave which we have not seen the likes of previously and which unfortunately is yet to end.”
The entity’s Health Ministry is still unable to ascertain the new subvariant’s potential impact on the current wave of infections sweeping the country, or whether it is likely to replace the omicron variant and to set new record case numbers.
The UK Health Security Agency reported last Friday that there was an increased growth rate of BA.2 compared with BA.1 in all regions of Britain where there were enough cases to compare, and that “the apparent growth [difference] is currently substantial.”
Experts say the BA.2 subvariant is a relative of omicron, and while similar to BA.1 in many respects, it also appears to diverge from its parent variant across a number of traits.
“They developed from the same evolutionary branch and it operates in the same way as omicron,” said a senior laboratory virologist. “It behaves differently in different countries. In some countries we have seen it spread rapidly along with a decline in omicron, and in others it has spread slowly where omicron was at a peak. But it appears that this depends on other parameters such as the level of vaccination of the population, so it is difficult to analyze and make predictions."
According to Dr. Yotam Shenhar, head of laboratoris at Leumit Health Services, “At this stage we do not have well-founded data. What we know at the moment is that on the one hand it is similar to omicron and may replace it, and on the other that there is no evidence of broad infection with both strains, so it is unlikely to lead to a new wave after the omicron wave.”
The subvariant's similarity to omicron is a relief insofar as the relatively mild symptoms it causes, but another trait is nevertheless causing concern among experts: BA.2 is even more infectious than omicron. “A number of studies show that it is more infectious than omicron,” said Prof. Cyrille Cohen, head of the immunotherapy lab at Bar-Ilan University.
According to a report by the UK health services, it is 1.3 times more infectious than omicron, while a study in Denmark found it to be 1.5 times more infectious. There are signs that vaccinations offer greater protection against BA.2 compared to BA.1, at a level of 70 percent protection against symptomatic illness two weeks after administration of the vaccine for BA.1, compared to 63 percent for omicron. “This counters the claim that vaccines could encourage the emergence of new variants. In general, we see that what contributes to new variants is the pace of infection, not whether the population is vaccinated or not,” said Cohen.
On the possibility of re-infection with the BA.2 subvariant among people who have already been infected with omicron, Cohen said there are initial signs of re-infection, but it is not yet possible to draw hard conclusions. “It’s probably rare and at this stage we cannot talk of a significant process of re-infection. However, more data is required, and we cannot say unequivocally. The encouraging part of this is that it appears the severity of the subvariant is no different to that of omicron.”
Amid the omicron wave, scientists and health officials have been hard-pressed with evaluating the risk of the new subvariant. “It’s hard to know why the BA.2 subvariant has become dominant is some places like Denmark and the Philippines, while in others it hasn’t,” said Cohen.
