The “stealth Omicron” variant BA.2 is dominating the world

The virus strain BA.2 is raising concerns about the possibility of a new wave of COVID-19 epidemics.

According to the World Health Organization, BA.2 accounts for 86% of current COVID-19 cases. This sub-variant of the highly contagious version of Omicron called BA.2 is even more contagious than its highly contagious Omicron “siblings”, BA.1 and BA. 1.1. However, the evidence to date suggests that BA.2 is not likely to cause serious illness.

As with other variants in the Omicron lineage, the COVID-19 vaccine against BA.2 is less effective than earlier variants such as Alpha or the original virus strain, and protection diminishes over time. According to data from the UK Health Security Agency, the vaccine’s protection is restored with a booster shot, particularly effective in preventing hospitalization and death.

Globally, the rapid spread of BA.2 is attributed to the recent increase in the number of COVID-19 cases in China as well as the record infection in European countries. Europe like Germany and Great Britain. However, some European countries are now seeing the number of new infections slow down, or even decline.

BA.2 is called the “stealth variant” because it’s harder to track. A missing gene in the BA.1 variant makes BA.2 undetectable through a conventional PCR test. Besides BA.2, another “brother virus” strain, BA.3 is also increasing in prevalence but currently at low levels, which can only be found by genome sequencing.

BA.2 accounts for 86% of current COVID-19 cases (Image: AP)

A key concern about BA.2 is whether it can re-infect people who have had BA.1, especially as some countries appear to be experiencing “double peaks” in infection rates. surprisingly close together. However, data from the UK and Denmark have shown that, while the Omicron variant can reinfect people with other variants, such as Delta, only a small number of cases of BA reinfection. 2 in people who had BA.1 found so far in tens of thousands of cases.

According to the scientists, one possible explanation for the recent increase in BA.2 could be that this global increase occurred at the same time as many countries were lifting public health interventions. .

“In some ways, it’s possible that BA.2 circulates when people stop wearing masks,” said Dr. Andrew Pekosz, a virologist at the Johns Hopkins Bloomberg School of Public Health in Baltimore.

As a result, other US experts like Eric Topol, director of the Scripps Translational Research Institute in La Jolla, California, say it’s “a bit early” to predict whether the US will also see a wave of BAs. .2 significant or not.

However, whatever the reason for the rise in BA.2, the scientists say, it is a reminder that the SARS-CoV-2 virus continues to cause harm, especially to unvaccinated and vulnerable populations.

“This is still a huge public health problem and it will continue to be,” said Mark Woolhouse, an epidemiologist at the University of Edinburgh.