sars-cov-2 delta variant sars-cov-2 delta variant the delta variant (b.1.617.2) was 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. for lineage b.1.617.1, see sars-cov-2 kappa variant. sars-cov-2 variantscientifically accurate atomic model of the external structure of sars-cov-2. each "ball" is an atom.general detailssymptoms none headache sore throat running nose fever major variants alpha (b.1.1.7) beta (b.1.351) gamma (p.1) delta (b.1.617.2) omicron (b.1.1.529) ba.1 (b.1.1.529.1)ba.2 (b.1.1.529.2)ba.3 (b.1.1.529.3)ba.4 (b.1.1.529.4)ba.5 (b.1.1.529.5) part of a series on thecovid-19 pandemicscientifically accurate atomic model of the external structure of sars-cov-2. each "ball" is an atom. covid-19 (disease) sars-cov-2 (virus) cases deaths timeline 2019 2020 january responses february responses march responses april responses may responses june responses july responses august responses september responses october responses november responses december responses 2021 january responses february responses march responses april responses may responses june responses july responses august responses september responses october responses november responses december responses 2022 january responses february responses march responses april responses may responses june responses july responses august responses september responses october responses november december 2023 january february march april may locations by country and territory africa antarctica asia europe north america oceania south america by conveyance cruise ships naval ships international response endemic phase evacuations face masks international aid investigations into origin lockdowns by country misinformation by governments fake treatments social distancing software travel united nations world health organization wto ip waiver undercounting of deaths covid-19 apps zero-covid national responses africa china european union germany ghana india ireland netherlands new zealand nigeria philippines russia sweden uk government us federal government vietnam medical response disease testing breathalyzer development drug development drug repurposing public health mitigation vaccines history research vitt deployment authorizations operation warp speed misinformation and hesitancy us vaccine card vaccine passports current vaccines coronavac covaxin convidecia janssen medigen moderna novavax oxford–astrazeneca pfizer–biontech sinopharm bibp sputnik v variants variants of concern alpha beta gamma delta omicron other variants epsilon zeta eta theta iota kappa lambda mu cluster 5 lineage b.1.617 economic impact and recession arts and culture aviation cannabis cinema films disney fashion financial markets food industry food security journalism music performing arts retail shipping television us sportscasting programs tourism video games by country canada india ireland malaysia new zealand russia uk us by sport association football baseball basketball combat sports cricket disc golf gaelic games gridiron football ice hockey motorsport rugby league impacts animals black people crime death rates by country disability domestic violence emergency evacuations education female environment hospitals language lgbt community long-term care media coverage mental health symptoms migration military notable deaths other health issues politics diplomacy popular culture protests pregnancy prisons religion catholic church hajj science and technology social media strikes suicides telehealth xenophobia and racism society ireland malaysia new zealand russia uk us covid-19 portal 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. 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; 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. immunity from previous recovery or covid-19 vaccines are effective in preventing severe disease or hospitalisation from infection with the variant. 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); the uk's sage using may data estimated a "realistic" possibility of being 50% more transmissible. 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. the variant is thought to be partly responsible for india's deadly second wave of the pandemic beginning in february 2021. it later contributed to a third wave in fiji, the united kingdom and south africa, and the who warned in july 2021 that it could have a similar effect elsewhere in europe and africa. by late july, it had also driven an increase in daily infections in parts of asia, the united states, australia, and new zealand. classification the delta variant has mutations in the gene encoding the sars-cov-2 spike protein causing the substitutions d614g, t478k, p681r and l452r. it is identified as the 21a, 21i, and 21j clades under the nextstrain phylogenetic classification system. names the virus has also been referred to by the term "indian variant" as it was originally detected in india. however, the delta variant is only one of three variants of the lineage b.1.617, all of which were first detected in india. at the end of may 2021, the who assigned the label delta to lineage b.1.617.2 after introducing a new policy of using greek letters for variants of concern and variants of interest. other sublineages of b.1.617 there are three sublineages of lineage b.1.617 categorised so far. b.1.617.1 (kappa variant) was designated a variant under investigation in april 2021 by public health england. later in april 2021, two other variants b.1.617.2 and b.1.617.3 were designated as variants under investigation. while b.1.617.3 shares the l452r and e484q mutations found in b.1.617.1, b.1.617.2 lacks the e484q mutation. b.1.617.2 has the t478k mutation, not found in b.1.617.1 and b.1.617.3. simultaneously, the ecdc released a brief maintaining all three sublineages of b.1.617 as voi, estimating that a "greater understanding of the risks related to these b.1.617 lineages is needed before any modification of current measures can be considered". mutations amino acid mutations of sars-cov-2 delta variant plotted on a genome map of sars-cov-2 with a focus on spike. defining mutations in thesars-cov-2 delta variant gene nucleotide amino acid orf1b p314l p1000l spike g142d t19r r158g l452r t478k d614g p681r d950n e156del f157del m i82t n d63g r203m d377y orf3a s26l orf7a v82a t120i sources: cdc covariants.org the delta/ b.1.617.2 genome has 13 mutations (15 or 17 according to some sources, depending on whether more common mutations are included) which produce alterations in the amino-acid sequences of the proteins it encodes. the list of spike protein mutations is: 19r, (g142d), δ156-157, r158g, l452r, t478k, d614g, p681r, d950n according to gvn, or t19r, g142d, del 156–157, r158g, l452r, t478k, d614g, p681r according to genscript four of them, all of which are in the virus's spike protein code, are of particular concern: d614g. the substitution at position 614, an aspartic acid-to-glycine substitution, is shared with other highly transmissible variants like alpha, beta and gamma. t478k. the exchange at position 478 is a threonine-to-lysine substitution. l452r. the substitution at position 452, a leucine-to-arginine substitution, confers stronger affinity of the spike protein for the ace2 receptor and decreased recognition capability of the immune system. p681r. the substitution at position 681, a proline-to-arginine substitution, which, according to william a. haseltine, may boost cell-level infectivity of the variant "by facilitating cleavage of the s precursor protein to the active s1/s2 configuration". the e484q mutation is not present in the b.1.617.2 genome. lineages as of august 2021, delta variants have been subdivided in the pango lineage designation system into variants from ay.1 to ay.28. however, there is no information on whether such classification correlates with biological characteristic changes of the virus. it is said that, as of august 2021, ay.4 to ay.11 are predominant in the uk, ay.12 in israel, ay.2, ay.3, ay.13, ay.14, ay.25 in the us, ay.20 in the us and mexico, ay.15 in canada, ay.16 in kenya, ay.17 in ireland and northern ireland, ay.19 in south africa, ay.21 in italy and switzerland, ay.22 in portugal, ay.24 in indonesia, and ay.23 in indonesia, singapore, japan, and south korea. "delta plus" variant