Covid delta variant has been detected in more than 185 countries to date, she told in a WHO social media interaction. According to Centers for Disease Control and Prevention (CDC), the Delta variant is highly contagious, more than 2x as contagious as previous variants.
Some data suggested that the Delta variant might cause more severe illness than previous variants in unvaccinated people. 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.