Delta Variant
The Delta variant is a variant of SARS-CoV-2, the virus that causes COVID-19. It was first detected in India in late 2020. The Delta variant was named on 31 May 2021 and had spread to over 179 countries by 22 November 2021. The World Health Organization indicated in June 2021 that the Delta variant was becoming the dominant strain globally. It has mutations in the gene encoding the SARS-CoV-2 spike protein causing the substitutions T478K, P681R and L452R, which are known to affect transmissibility of the virus as well as whether it can be neutralised by antibodies for previously circulating variants of the COVID-19 virus. It is thought to be one of the most transmissible respiratory viruses known.