The "worrying" Delta variant, which has been identified in 185 countries to date, has almost displaced the three previous "worrying" variants, Alpha, Beta and Gamma, which now account for less than 1% of all cases. genome analysis, the World Health Organization said today.
All viruses, including Covid-2-causing SARS-CoV-19, mutate.
The emergence, at the end of 2020, of variants that posed an increased risk to public health worldwide led the WHO to label some of them as "worrying" and others as "variants of interest" in order to prioritize their research and monitoring worldwide.
"The prevailing variant that is being released now is the Delta. "In fact, less than 1% of the available genome analyzes are (of 'worrying variants') Alpha, Beta and Gamma," said Maria Van Kerkov, a senior WHO official, answering questions from users on social networking sites.
"This virus (the Delta variant) has become more powerful, it is more contagious and it competes and replaces the others that are circulating," he added.
At present, the WHO describes all four variants as "worrying". Until now, he considered four other "variants of interest", Ita, Giota, Kappa and Lambda, but the first three of them have been declassified, Van Kerkov said.