SARS-CoV-2 Delta variant

Main article: Variants of SARS-CoV-2
For lineage B.1.617.1, see SARS-CoV-2 Kappa variant.

This article is about a variant of the virus that causes COVID-19. Not to be confused with the Deltacoronavirus grouping of coronavirus species that affects birds and non-human mammals.

SARS-CoV-2 Variant
Scientifically accurate atomic model of the external structure of SARS-CoV-2. Each "ball" is an atom.
Scientifically accurate atomic model of the external structure of SARS-CoV-2. Each "ball" is an atom.
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The Delta variant (B.1.617.2) was[3][4] a variant of SARS-CoV-2, the virus that causes COVID-19. It was first detected in India on 5 October 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 (WHO) indicated in June 2021 that the Delta variant was becoming the dominant strain globally.[5]

It has mutations in the gene encoding the SARS-CoV-2 spike protein[6] causing the substitutions T478K, P681R and L452R,[7][8] 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.[9] In August 2021, Public Health England (PHE) reported secondary attack rate in household contacts of non-travel or unknown cases for Delta to be 10.8% vis-à-vis 10.2% for the Alpha variant;[10] the case fatality rate for those 386,835 people with Delta is 0.3%, where 46% of the cases and 6% of the deaths are unvaccinated and below 50 years old.[11] Immunity from previous recovery[12][13] or COVID-19 vaccines are effective in preventing severe disease or hospitalisation from infection with the variant.[14]

On 7 May 2021, PHE changed their classification of lineage B.1.617.2 from a variant under investigation (VUI) to a variant of concern (VOC) based on an assessment of transmissibility being at least equivalent to B.1.1.7 (Alpha variant);[15] the UK's SAGE using May data estimated a "realistic" possibility of being 50% more transmissible.[16] On 11 May 2021, the WHO also classified this lineage VOC, and said that it showed evidence of higher transmissibility and reduced neutralisation. On 15 June 2021, the Centers for Disease Control and Prevention (CDC) declared Delta a variant of concern.[17]

The variant is thought to be partly responsible for India's deadly second wave of the pandemic beginning in February 2021.[18][19][20] It later contributed to a third wave in Fiji, the United Kingdom[21][22][23] and South Africa,[24] and the WHO warned in July 2021 that it could have a similar effect elsewhere in Europe and Africa.[25][24] By late July, it had also driven an increase in daily infections in parts of Asia,[26] the United States,[27] Australia, and New Zealand.[28]

  1. ^ a b c d Grover, Natalie (14 June 2021). "Delta variant Covid symptoms 'include headaches, sore throat and runny nose'". The Guardian. London. Archived from the original on 14 June 2021. Retrieved 30 June 2021.
  2. ^ a b Roberts, Michelle (14 June 2021). "Headache and runny nose linked to Delta variant". BBC News. London. Archived from the original on 14 June 2021. Retrieved 2 July 2021.
  3. ^ "Tracking SARS-CoV-2 variants". www.who.int. Archived from the original on 9 June 2021. Retrieved 17 August 2022.
  4. ^ "Variants of concern". CDGN. Archived from the original on 13 July 2021. Retrieved 17 August 2022.
  5. ^ Lovelace, Berkeley Jr. (18 June 2021). "WHO says delta is becoming the dominant Covid variant globally". CNBC. Archived from the original on 4 November 2021. Retrieved 1 November 2021.
  6. ^ Cite error: The named reference :3 was invoked but never defined (see the help page).
  7. ^ "expert reaction to VUI-21APR-02/B.1.617.2 being classified by PHE as a variant of concern". sciencemediacentre.org. 7 May 2021. Archived from the original on 13 July 2021. Retrieved 18 June 2021.
  8. ^ Cite error: The named reference SGDB was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference ECDC1 was invoked but never defined (see the help page).
  10. ^ "Technical Briefing 20 SARS-CoV-2 variants of concern and variants under investigation in England" (PDF). 6 August 2021. Archived (PDF) from the original on 15 December 2021. Retrieved 10 August 2021. This article contains OGL licensed text This article incorporates text published under the British Open Government Licence v3.0:
  11. ^ "Technical Briefing 21 SARS-CoV-2 variants of concern and variants under investigation in England" (PDF). Public Health England. 20 August 2021. Archived (PDF) from the original on 23 July 2021. Retrieved 28 August 2021. This article contains OGL licensed text This article incorporates text published under the British Open Government Licence v3.0:
  12. ^ Sivan Gazit (25 August 2021). "Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections". medRxiv 10.1101/2021.08.24.21262415v1. The study in Israel tracked 46035 unvaccinated recovered and 46035 vaccinated people of the same age distribution, to compare their infection occurrence in the follow-up period. 640 infections and 21 hospitalization in the vaccinated group and 108 infections and 4 hospitalizations in the recovered group were recorded.
  13. ^ "Past Covid-19 reduces risk of reinfection from Delta variant more than Pfizer vaccine". Bloomberg. 27 August 2021. Archived from the original on 21 October 2021. Retrieved 31 August 2021.
  14. ^ Burn-Murdoch, John; Mancini, Donato Paolo (9 July 2021). "How effective are coronavirus vaccines against the Delta variant?". www.ft.com. Archived from the original on 20 December 2021. Retrieved 23 July 2021.
  15. ^ "Confirmed cases of COVID-19 variants identified in UK". www.gov.uk. 7 May 2021. Archived from the original on 7 May 2021. Retrieved 7 May 2021. This article contains OGL licensed text This article incorporates text published under the British Open Government Licence v3.0:
  16. ^ "Is The Variant From India The Most Contagious Coronavirus Mutant On The Planet?". NPR. 14 May 2021. Archived from the original on 2 August 2021. Retrieved 19 July 2021. cited "Eighty-ninth SAGE meeting on COVID-19, 13 May 2021 (Held via Video Teleconference)" (PDF). UK Government. 13 May 2021. Archived (PDF) from the original on 16 May 2021. Retrieved 19 July 2021.
  17. ^ "06/15/2021: Lab Advisory: CDC Classifies SARS-CoV-2 Variant B.1.617.2 (Delta) a Variant of Concern". CDC. 15 June 2021. Archived from the original on 9 July 2021. Retrieved 7 July 2021.
  18. ^ WHO labels a Covid strain in India as a 'variant of concern' — here's what we know Archived 1 June 2021 at the Wayback Machine, CNBC, 11 May 2021.
  19. ^ "WHO says India Covid variant of 'global concern'" Archived 29 May 2021 at the Wayback Machine, BBC News, 11 May 2021.
  20. ^ Narang, Deepanshu (22 April 2021). "COVID-19: The Second Wave May Not Be the Last – but Which One Will Be? – The Wire Science". Archived from the original on 15 May 2021. Retrieved 20 May 2022.
  21. ^ Mishra, Swapnil; Mindermann, Sören; Sharma, Mrinank; Whittaker, Charles; Mellan, Thomas A.; Wilton, Thomas; Klapsa, Dimitra; Mate, Ryan; Fritzsche, Martin; Zambon, Maria; Ahuja, Janvi (1 September 2021). "Changing composition of SARS-CoV-2 lineages and rise of Delta variant in England". eClinicalMedicine. 39: 101064. doi:10.1016/j.eclinm.2021.101064. ISSN 2589-5370. PMC 8349999. PMID 34401689.
  22. ^ Callaway, Ewen (22 June 2021). "Delta coronavirus variant: scientists brace for impact". Nature. 595 (7865): 17–18. Bibcode:2021Natur.595...17C. doi:10.1038/d41586-021-01696-3. PMID 34158664. S2CID 235609029.
  23. ^ Rob Picheta (30 June 2021). "Britain thinks it can out-vaccinate the Delta variant. The world isn't so sure". CNN. Archived from the original on 1 July 2021. Retrieved 2 July 2021.
  24. ^ a b "Health service buckling as third coronavirus wave fuelled by Delta variant sweeps across South Africa". the Guardian. 4 July 2021. Archived from the original on 7 July 2021. Retrieved 7 July 2021.
  25. ^ Ellyatt, Holly (1 July 2021). "New Covid wave could be imminent as delta variant sweeps Europe, WHO says". CNBC. Archived from the original on 2 July 2021. Retrieved 2 July 2021.
  26. ^ "Delta variant: Which Asian countries are seeing rising cases?". BBC News. 19 July 2021. Archived from the original on 2 November 2021. Retrieved 23 July 2021.
  27. ^ "US in 'another pivotal moment' as Delta variant drives surge in Covid cases". the Guardian. 23 July 2021. Archived from the original on 22 October 2021. Retrieved 23 July 2021.
  28. ^ "New Zealand suspends quarantine-free travel bubble with Australia". ITV News. 23 July 2021. Archived from the original on 25 November 2021. Retrieved 23 July 2021.