Geneva: The WHO on Tuesday said that the Delta variant of coronavirus which now represents a tiny fraction of the samples being sequenced, is overwhelming the three other Covid-19 variants of concern.
"Less than one per cent each of Alpha, Beta and Gamma are currently circulating. It's predominantly Delta around the world," said Maria Van Kerkhove, the World Health Organization's technical lead on Covid-19.
Delta "has become more fit, it is more transmissible and it is out-competing, it is replacing the other viruses that are circulating," she told a WHO social media to live interaction, adding that Delta had been detected in more than 185 countries to date.
In late 2020, the emergence of variants that posed an increased risk to global public health prompted the WHO to start characterising them as variants of interest, and the more-worrying variants of concern, to inform the response to the pandemic.
The UN health agency decided to name the variants after the letters of the Greek alphabet, to avoid the countries that first detected them being stigmatised.
Besides the four variants of concern, there are also five variants of interest, but Van Kerkhove said three of them -- Eta, Iota and Kappa -- were now being downgraded to variants under monitoring.
"This is due to changes in circulation and that the variants of interest are just out-competed by the variants of concern. They're just not taking hold," she said.