Omicron sub-variant BA.2 is now dominant worldwide (representative image). Photograph:( Zee News Network )
As it is slightly harder to track, BA.2 is also called the "stealth variant". BA.1 is tracked through a common PCR test by default due to a missing gene. While BA.2 and another sibling, BA.3, can be found only by genomic sequencing
Even after causing havoc for last two years, coronavirus seems to have been refusing to die down.
Currently, different parts of the world have been witnessing a surge in the number of cases due to the spread of a sub-variant of the highly transmissible Omicron variant of coronavirus.
The sub-variant is called BA.2. It is now dominant worldwide.
What is the BA.2 variant?
Amid the surge in Omicron cases, British health officials had earlier detected growing cases of BA.2 variant. In total, Omicron has three sub-strains - BA.1, BA.2 and BA.3.
As it is slightly harder to track, BA.2 is also called the "stealth variant". BA.1 is tracked through a common PCR test by default due to a missing gene. While BA.2 and another sibling, BA.3 can be found only by genomic sequencing.
Should you be concerned?
According to the World Health Organization, BA.2 now represents around 86% of all sequenced cases. It is more transmissible than other sub-variants, like BA.1 and BA.1.1. But the evidence so far suggests that it is less likely to cause severe infection.
Watch: Shanghai tightens COVID lockdown: Curbs imposed on highway traffic
Vaccines are also less effective against BA.2. As per UK Health Security Agency data, protection gets restored by a booster jab, particularly for preventing hospitalisation and death.
BA.2 has led to surges in China and European countries like Germany and the UK. It is also raising concern over the potential for a new wave in the United States.
Can it re-infect people?
As a number of countries are experiencing "double peaks" in infection rates simultaneously, a key concern about BA.2 is that whether it could re-infect people who had already had BA.1.
But data from both the UK and Denmark show that while Omicron can reinfect people, who had other variants, like Delta, only a handful of BA.2 reinfections in people, who earlier had BA.1 have been found so far.
According to the scientists, a explanation for the recent spike in BA.2 cases could be the global uptick happened at the same time in many countries after lifting of public health interventions.
"In some ways, it could just be that BA.2 was the variant that was circulating when all these people stopped wearing masks," said Dr Andrew Pekosz, virologist, Johns Hopkins Bloomberg School of Public Health in Baltimore.
Other US experts, such as Eric Topol, director, Scripps Research Translational Institute in La Jolla, California, said it was "a little too early" to call whether the US too would see a significant BA.2 wave.
"It is still a huge public health problem and it is going to continue to be," said Mark Woolhouse, epidemiologist, the University of Edinburgh.
(With inputs from agencies)