severe acute respiratory syndrome coronavirus 2; SARS-CoV2; Wuhan coronavirus

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  • Covariants is a free & open source resource that provides an overview of SARS-CoV2 variants & mutations[21]





  • mutation VUI-202012/01 (B.1.1.7 dubbed 'alpha') discovered in the United Kingdom[9][33]
    • has been found in Australia, Denmark, Iceland, Italy. the Netherlands, Japan, Australia, & Lebanon
    • first case in U.S. found in Colorado[10]
    • does not appear to cause more severe disease than other variants[9][24]
    • English variant B.1.1.7 may be associated with higher risk of mortality than wild type SAS CoV2 (RR=1.6)[11][18][21]
    • both vaccines being used in the U.K. are effective against the variant.
    • appears to be a more transmissible (contagious) variant[9][10]
      • 43-90% higher transmissibility than earlier strains[17]
    • affects higher proportion of younger persons < 20 years of age[10]
    • predicted to become most prevalent strain of virus in U.S. by March[12]



  • variant 20J/501Y.V3 or P.1 variant dubbed gamma discovered in Brazil
    • P.1 variant is related to South African B.1.351[5][20]
    • found in U.S. & is more transmissible[14][28]
    • neutralizing antibodies from Moderna & Pfizer vaccines 5- to 6-fold less effective against the variants discovered in Brazil[20]
    • breakthrough infections in fully vaccinated in French Guiana (87% symptomatic, no severe infections) 56% had received Pfizer vaccine[47]
    • rapid spread of Gamma variant in Brazil, replaced other variants in < 3 months[59]




  • Eris named for a dwarf planet in the solar system between Neptune & Pluto[118]
  • EG.5 accounts for 17% of all U.S. COVID infections Aug 7, 2023
    • up 12% from previous week[118]
  • the most prevalent COVID-19 variants globally one August 23, 2023 were XBB.1.16 & EG.5 each comprising 25% of total[121]
  • EG.5 is a descendant of the XBB strains
  • no indication so far that EG.5 is more contagious or severe than other variants
  • current vaccines protect against the variant (CDC)[118]


  • B.1.526 (dubbed 'iota'): reduced efficacy of some antibody treatments
    • found in New York Feb 2021[16]
    • most common mutations L5F, T95I, D253G, E484K or S477N, D614G, & A701V[16]



  • P.2 (dubbed 'zeta'): decreased response to some antibody treatments.
  • B.1.617.1 (dubbed 'kappa'): decreased response to some antibody treatments
  • B.1.617.3 (no designation): decreased response to some antibody treatments


Omicron variant

  • variant, called B.1.1.529 1st identified in Botswana
  • data suggest Omicron may be less severe variant than Delta[71]
  • Omicron variant accountd for almost 100% of COVID-19 cases in the United States Feb 2022
  • the 7-day average of daily COVID-related deaths hit 2,600 in Feb 2022, the highest rate in about a year
    • Omicron appears to be less severe than Delta, but is not 'mild' (WHO)[76]
  • Omicron ~1/2 as likely as Delta to cause long Covid-19 (~5%)[96]
  • Omicron variant could make it more likely that people will need a 4th Covid-19 vaccine earlier than expected[67]
  • prior SARS-CoV-2 infection less effective at preventing reinfection with Omicron vs prior variants; 56% for Omicron, 90% for Alpha, 86% for Beta, 92% for Delta[82]
    • however, no reinfections resulted in death
    • prior Omicron infection 88% effective at preventing severe/critical reinfection[82]
  • Regen-Cov less effective against Omicron variant in preliminary tests[65]
  • Pfizer CEO thinks it unlikely Paxlovid will be less effective against Omicron[66]
  • Moderna 50 ug booster increases antibodies to Omicron by 37-fold within 1 month[70]
  • a 3rd dose of Pfizer or Moderna mRNA vaccine increases cross-reactive antibody responses sufficient to neutralize Omicron[77]
  • majority of T cell response, induced by vaccination or natural infection, cross-recognises the Omicron variant[72]
  • new, highly contagious subvariant of Omicron has emerged BA.2, or 'son of Omicron'[78]
    • Omicron BA.1 is the original Omicron[86]
    • Omicron subvariant BA.2 1.5-fold more contagious than BA.1[80]
    • Omicron subvariant BA.2 23% of SARS-CoV2 variants in U.S. March 16, 2022[87], 55% of COVID variants in the U.S. March 26, 2022 according to CDC estimates
    • BA.5 Omicron subvariant makes up ~80% of COVID-19 cases July 21, 2022[102]
      • BA.5 Omicron subvariant makes up ~68% of COVID-19 cases Oct 17, 2022[107]
    • BA.2 may cause more severe disease than BA.1[84]
    • BA.2 causes less severe disease than BA.1[89]
    • BA.2 known as stealth variant because it is more difficult to detect[86]
    • BA.2.12.1 accounts for 26% of sequenced genomes in North America May 2022[94]
    • no real-world evidence that BA.2 causes more severe disease than BA.1[85]
    • BA.2.75 first detected in India in May 2022, by July 2022 found in least 10 countries in Asia, Europe, North America, & Australia[100]
      • more worrisome BA.2.75.2[107]
    • BA.2.86 is a highly mutated variant
      • detected in the United States, Denmark & Israel[119]
      • may be more more capable than older variants in causing infection in previously infected or vaccinated persons[120]
      • too soon to know if BA.2.86 causes more severe illness than previous variants[120]
    • Omicron variants BA.3 & BA.4 identified[86]
    • Omicron variants BA.4 & BA.5 identified in U.S.[95]
      • prior Omicron infection provides some protection against BA.4 & BA.5 variants[103]
      • recovery from Omicron BA.2 or BA.2.12.1 probably does not confer protection against Omicron BA.4 or BA.5[95][101]
    • BA.5=83%, BA.4.6=12%, BF.7=2.3%, BA.4 & BA.2.76 each=1.4% of circulating strains in U.S. Sept 18-24 2022[106]
    • Omicron BA.2.12.1, BA.4,& BA.5 subvariants escape neutralizing antibodies induced by both vaccination & infection[97][104]
    • similar protection against severe, critical, or fatal Omicron infection conferred by previous infection, vaccination, or a combination of both[99]
    • a third vaccine dose results in recall & expansion of SARS-CoV-2 Spike protein- specific memory B cells, leading to neutralizing antibodies with enhanced potency & breadth against variants[104]
    • night sweats associated with Omicron infection, especially BA.5[98]
  • Omicron XE a combination of the original Omicron strain & subvariant Omicron BA.2 identified in the United Kingdom[92]
  • BQ.1.1, BA.2.3.20, & XBB variants of concern[107]
    • BQ.1 & BQ.1.1 make up ~20% of COVID-19 cases in the New York & New Jersey region, as of Oct 17, 2022 & 12% of strains in U.S.[108]
    • BQ.1 is a BA.5 sub-lineage, thus some cross protection anticipated for the current (October 2022) Pfizer & Moderna bivalent vaccines[107]
    • Omicron BQ & XBB subvariants may be resistant to Pfizer & Moderna bivalent vaccines[112]
    • XBB is 17% of strains in Singpore with 92% vaccination rate Oct 18 2022[108]
    • XBB was estimated to account for 18.3% of the COVID-19 cases in the United States & 50% of cases in the Northeast in the week ended Dec. 24, 2022[113]
    • XBB.1.5 40%, BQ.1.1 27%, BQ.1 18% of US cases in week ending Dec. 31, 2022[114][115]
    • XBB.1.5 (Kraken variant) may be most infectious SARS CoV2 variant yet[115]
    • XBB.1.5 is so transmissible that everyone is at risk of infection, even if prior infection & fully vaccinated[115]
    • XBB.1.16 Arcturus (formally, Omicron subvariant XBB.1.16)
  • Omicron BN.1 linked to ~4.3% of cases in U.S. Nov. 2022[109]
  • during Omicron predominance, COVID-19 hospitalization rates in Los Angeles County among unvaccinated persons were 23.0 times those of fully vaccinated persons with a booster, & 5.3 times those among fully vaccinated persons without a booster[81]
  • Omicron survives ~ as long as Alpha on plastic (193 hours average) & 21 hours on skin[79]
  • Omicron variant CH.1.1 'Orthrus' named after a monster canine in Greek mythology has a mutation, L452R, present in the Delta variant & Omicron variants BA.4 & BA.5
    • CH.1.1 emerged in Southeast Asia in November 2022, now accounts for ~ 1/4 of cases in Feb 2023 in the U.K. & New Zealand[116]
  • Omicron variant HV.1 major circulating strain in U.S. Fall of 2023
    • sublineage of omicron XBB.1.9.2 & a direct descendent of EG.5,
    • subvariants XBB.1.5, EG.5 & FL.1.5.1 on the rise in U.S. Fall of 2023[122]
    • JN.1 declared variant of interest by WHO in Dec 2023[123]
  • new variant FLiRT identified in U.S. 2024[124]


  • new variant, known as C.1.2[55]
    • first detected in South Africa in May 2021
    • now spread to most South African provinces & to 7 other countries in Africa, Europe, Asia & Oceania
    • contains many mutations associated in other variants with increased transmissibility & reduced sensitivity to neutralising antibodies, but in a different mix
    • most distant variant from the original Wuhan coronavirus, with 44-59 mutations[55]


R.1 variant 1st reported in Japan


  • viruses have only been sequenced from ~51,000 of 17 million U.S. cases in Dec 2020[15]
  • $1.7 billion national network to identify & track coronavirus mutations in the U.S. is in the works[25]
  • Covid-19 is likely here to stay as SARS-CoV2 continues to mutate in unvaccinated countries across the world & previous hopes of eradicating it diminish (WHO)[56]

early reports

human genetic factors

other issues

Can SARS CoV2 RNA genes insert into human DNA?[31]

Clinical manifestations


Diagnostic procedures




Comparative biology

More general terms

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Additional terms


  1. 1.0 1.1 Lu R, Zhao X, Li J et al Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding. Lancet. 2020. Jan 30. PMID:
  2. 2.0 2.1 Universita di Bologna The six strains of SARS-CoV-2 Science News. Aug 3, 2020
  3. 3.0 3.1 Walsh NK CNN Exclusive: WHO Wuhan mission finds possible signs of wider original outbreak in 2019. CNN Health. Feb 14, 2021
  4. 4.0 4.1 4.2 4.3 4.4 Zimmer C New California Variant May Be Driving Virus Surge There, Study Suggest New York Times. Jan 19, 2021
    By City News Service, Jan 18, 2021 New Coronavirus Strain Found in More Than One-Third of Cases in Cedars-Sinai Study.
    Zhang W, Davis BD, Chen SS et al Emergence of a Novel SARS-CoV-2 Variant in Southern California. JAMA. Published online February 11, 2021 PMID:
    Mascola ER, Graham BS, Fauci AS SARS-CoV-2 Viral Variants - Tackling a Moving Target. JAMA. Published online February 11, 2021 PMID:
  5. 5.0 5.1 5.2 More JP, Offit PA SARS-CoV-2 Vaccines and the Growing Threat of Viral Variants. JAMA. Published online January 28, 2021 PMID:
  6. 6.0 6.1 Kaplan S, Achenbach J This coronavirus mutation has taken over the world. Scientists are trying to understand why. Washington Post. June 29
    Carey B Did a Mutation Help the Coronavirus Spread? More Evidence, but Lingering Questions. New York Times. July 2, 2020
    Korber B et al Spike mutation pipeline reveals the emergence of a more transmissible form of SARS-CoV-2. bioRxiv. May 05, 2020
    Zhang L et al The D614G mutation in the SARS-CoV-2 spike protein reduces S1 shedding and increases infectivity. bioRxiv. June 12, 2020
    Olena A SARS-CoV-2 Genetic Variant May Be More Transmissible. The Scientist. Nove 25, 2020
  7. 7.0 7.1 Young BE, Fong SW, Chan YH et al Effects of a major deletion in the SARS-CoV-2 genome on the severity of infection and the inflammatory response: an observational cohort study. Lancet. August 18, 2020 PMID: PMCID: PMC7434477 Free PMC article
  8. 8.0 8.1 8.2 Smith C Another coronavirus mutation was discovered - and this one might be more dangerous. BGR. Dec 19, 2020
    Reuters Staff South Africa identifies new coronavirus strain causing surge in cases. Reuters Health & Pharma. Dec 18, 2020
    Liu M, Stobbe M Virus Variant From South Africa Detected in US for First Time. Medscape - Jan 28, 2021
    World Health Organization (WHO) New COVID-19 variants fuelling Africa's second wave. WHO News Release. Jan 28, 2021
    Money L First infections with South Africa coronavirus strain found in California. Los Angeles Times. Feb 10, 2021
    Mwenda M, Saasa N, Sinyange N, et al. Detection of B.1.351 SARS-CoV-2 Variant Strain - Zambia, December 2020. MMWR Morb Mortal Wkly Rep. ePub: 17 February 2021 PMID: Free article
  9. 9.0 9.1 9.2 9.3 Zitser J Alarm over a new COVID-19 variant in the UK. Boris Johnson calls an emergency meeting to combat the mutating coronavirus. Business Insider, Dec 19, 2020
    Berger M U.K. variant of coronavirus continues global spread, despite containment efforts. Washington Post. Dec 26, 2020
    Centers for Disease Control & Prevention (CDC) Implications of the Emerging SARS-CoV-2 Variant VOC 202012/01. COVID-19 (Coronavirua Disease) Dec. 22, 2020
  10. 10.0 10.1 10.2 10.3 Achenbach J, Guarino B, Sun LH, Stanley-Becker I First case of highly infectious coronavirus variant detected in Colorado. Washington Post. Dec 29, 2020
    Walker M Just How Much More Transmissible Is the New Coronavirus Variant? MedPage Today January 2, 2021
    Volz E, Mishra S, Chand M et al Report 42 - Transmission of SARS-CoV-2 Lineage B.1.1.7 in England: insights from linking epidemiological and genetic data. MRC Centre for Global Infectious Disease Analysis. Dec 31, 2020
  11. 11.0 11.1 Bruce A, Smout A British PM Says New Variant May Carry Higher Risk of Death. Medscape - Jan 22, 2021.
    Horby P, Huntley C, Davies N NERVTAG note on B.1.1.7 severity SAGE meeting paper. Jan 21, 2021
  12. 12.0 12.1 Galloway SE, Paul P, MacCannell DR, et al. Emergence of SARS-CoV-2 B.1.1.7 Lineage - United States, December 29, 2020 - January 12, 2021. MMWR Morb Mortal Wkly Rep. ePub: 15 January 2021 PMID: Free article
  13. 13.0 13.1 Hodcroft EB, Domman DB, Snyder DJ et al Emergence in late 2020 of multiple lineages of SARS-CoV-2 Spike protein variants affecting amino acid position 677. MedRxiv. Feb 14, 2021 Not indexed in PubMed
  14. 14.0 14.1 AMA Morning News. January 26, 2021 American Medical Association
  15. 15.0 15.1 AMA Morning News. Dec 23, 2020 American Medical Association
  16. 16.0 16.1 16.2 West AP Jr., Barnes CO, Yang Z et al SARS-CoV-2 lineage B.1.526 emerging in the New York region detected by software utility created to query the spike mutational landscape. bioRxiv. 2021. Feb 23 Not indexed in PubMed
    Annavajhala MK, Mohri H, Zucker JE A Novel SARS-CoV-2 Variant of Concern, B.1.526, Identified in New York. MedRxiv. 2021. Feb 25 Not indexed in PubMed
    Mandavilli A A New Coronavirus Variant Is Spreading in New York, Researchers Report. New York Times. Feb 25, 2021
  17. 17.0 17.1 Davies NG, Abbott S, Barnard RC et al Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England. Science 2021: March 3 PMID:
  18. 18.0 18.1 Challen R, Brooks-Pollock E, Read JM et al Risk of mortality in patients infected with SARS-CoV-2 variant of concern 202012/1: matched cohort study. BMJ 2021;372:n579 PMID: PMCID: PMC7941603 Free PMC article
  19. 19.0 19.1 Madhi SA, Baillie V, Cutland CL et al Efficacy of the ChAdOx1 nCoV-19 Covid-19 Vaccine against the B.1.351 Variant. N Engl J Med 2021. March 16 PMID:
  20. 20.0 20.1 20.2 20.3 Reuters Staff Multiple Variants Can 'Escape' Vaccines Medscape - Mar 17, 2021
    Garcia-Beltran WF, Lam EC, St. Denis K et al Multiple SARS-CoV-2 variants escape neutralization by vaccine-induced humoral immunity. Cell 2021. March 12 PMID: PMCID: PMC7837114 Free PMC article
  21. 21.0 21.1 21.2 Challen R et al. Risk of mortality in patients infected with SARS-CoV-2 variant of concern 202012/1: Matched cohort study. BMJ 2021 Mar 9; 372:n579 PMID: PMCID: PMC7941603 Free PMC article
    Davies NG et al. Increased mortality in community-tested cases of SARS-CoV-2 lineage B.1.1.7. Nature 2021. March 15 PMID:
  22. 22.0 22.1 Washington NL, Gangavarapu K, Zeller M et al Emergence and rapid transmission of SARS-CoV-2 B.1.1.7 in the United States. Cell (2021) April PMID:
  23. 23.0 23.1 Moyo-Gwete T, Madzivhandila M, Makhado Z et al Cross-Reactive Neutralizing Antibody Responses Elicited by SARS-CoV-2 501Y.V2 (B.1.351. N Engl J Med April 7, 2021 PMID:
  24. 24.0 24.1 Frampton D, Rampling T, Cross A et al Genomic characteristics and clinical effect of the emergent SARS-CoV-2 B.1.1.7 lineage in London, UK: a whole-genome sequencing and hospital- based cohort study. The Lancet Infectious Diseases. April 12, 2021 PMID: PMCID: PMC8041359 Free PMC article
    Graham MS, Sudre CH, May A et al Changes in symptomatology, reinfection, and transmissibility associated with the SARS-CoV-2 variant B.1.1.7: an ecological study. The Lancet Public Health. April 12,2021 PMID: Free PMC article.
  25. 25.0 25.1 American Medical Association (AMA) U.S. to set up $1.7B national network to identify, track coronavirus variants. AMA Morning News. April 19, 2021
  26. 26.0 26.1 26.2 Smith-Schoenwalder C CDC Details First Known Clusters of South African Variant in U.S. Without Travel Link. U.S. News & World Report. April 29, 2021
  27. 27.0 27.1 Hackethal V India's COVID-19 Variant: What We Know So Far. Not yet clear how much the current surge is driven by this new variant. MedPage Today April 29, 2021
  28. 28.0 28.1 Ellis R Study: Brazilian Variant May Be More Transmissible. Medscape - Apr 30, 2021.
    Faria NR, Mellan TA, Whittaker C et al Genomics and epidemiology of the P.1 SARS-CoV-2 lineage in Manaus, Brazil. Science 2021. April 14 PMID: Free PMC article
  29. 29.0 29.1 Associated Press Virus Variant First Identified in India Found in Nebraska Medscape. May 14, 2021
  30. 30.0 30.1 Reuters mRNA Vaccines Likely Effective Against India Variant. Medscape. May 14, 2021
    Edara VV, Lai L, Sahoo MK et al Infection and vaccine-induced neutralizing antibody responses to the SARS-CoV-2 B.1.617.1 variant. bioRxiv. May 10, 2021
  31. 31.0 31.1 31.2 Hackethal V Can COVID-19 Genes Integrate Into Human DNA? Debate rages over whether SARS-CoV-2 can insert bits of its RNA into the human genome. MedPage Today May 17, 2021
    Zhang L, Richards S, Kahil A et al SARS-CoV-2 RNA reverse-transcribed and integrated into the human genome. bioTxiv. Dec 11, 2020
    Zhang L, Richards A, Barrasa MI et al Reverse-transcribed SARS-CoV-2 RNA can integrate into the genome of cultured human cells and can be expressed in patient-derived tissues. PNAS May 25, 2021 118 (21) e2105968118 PMID:
    Yan B, Chakravorty S, Mirabelli S et al Host-virus chimeric eventsin SARS-CoV2 infected cells are infrequent and artifactual. J Virol. Online May 12, 2021 PMID:
  32. 32.0 32.1 Mueller B New Variant Posing Threat, as Global Vaccine Drive Falters . New York Times. May 24, 2021 (via MSN)
  33. 33.0 33.1 33.2 Callaway E Coronavirus variants get Greek names - but will scientists use them? Nature 2021. News June 1
  34. 34.0 34.1 Crist C Pfizer Vaccine Protects Less Against India Variant. Medscape - Jun 04, 2021.
    Wall EC, Wu M, Harvey R et al Neutralising antibody activity against SARS-CoV-2 VOCs B.1.617.2 and B.1.351 by BNT162b2 vaccination. Lancet 2021. June 3 PMID: PMCID: PMC8175044 Free PMC article
  35. 35.0 35.1 Christensen J CDC now calls coronavirus Delta variant a 'variant of concern' CNN Health. 2021. June 15
    Crist C CDC: Delta Variant From India a 'Variant of Concern' Medscape - Jun 16, 2021.
    Crist C Delta Variant Now Accounts for 83% of US Cases. Medscape - Jul 20, 2021.
  36. 36.0 36.1 36.2 O'Shea D Delta Variant Increases Hospitalisation but Vaccines Continue to Protect. Medscape - Jun 14, 2021.
    Sheikh A, McMenamin J, Taylor B, Robertson C for the Public Health Scotland and the EAVE II Collaborators. SARS-CoV-2 Delta VOC in Scotland: demographics, risk of hospital admission, and vaccine effectiveness. Lancet 2021. Jun 14;S0140-6736(21)01358-1 PMID:
    Twohig KA, Nyberg T, Zaidi A et al Hospital admission and emergency care attendance risk for SARS-CoV-2 delta (B.1.617.2) compared with alpha (B.1.1.7) variants of concern: a cohort study. The Lancet Infectious Diseases. 2021. August 27 PMID: PMCID: PMC8397301 Free PMC article
  37. 37.0 37.1 37.2 Thomas N. The Delta variant is on its way to becoming globally dominant, WHO chief scientist says. CNN Live Updates. June 18, 2018
  38. Acharya B, Jamkhandikar S. What Is the Delta Variant of Coronavirus With K417N Mutation? Medscape - Jun 23, 2021.
    Crist C India Signals Alarm About New 'Delta Plus' Variant. Medscape - Jun 28, 2021.
  39. 39.0 39.1 39.2 Fiore K What Doctors Should Know About Delta. Here's the latest on transmissibility, virulence, vaccine efficacy, and more. MedPage Today June 29, 2021
  40. 40.0 40.1 40.2 Lalter L US 'Strike Teams' to Fight Delta COVID in 1000 Counties. Medscape - Jul 01, 2021.
    Crist C Delta Becomes Dominant CoronavirusVariant in US Medscape - Jul 07, 2021.
  41. 41.0 41.1 Fiore K Should We Be Concerned About the Lambda Variant? With its novel mutations, the variant first identified in Peru is being watched closely. MedPage Today July 7, 2021
    Tada T, Zhou H, Dcosta BM et al SARS-CoV-2 Lambda Variant Remains Susceptible to Neutralization by mRNA Vaccine-elicited Antibodies and Convalescent Serum. bioRxiv 2021. Jul 3 Not indexed in PubMed
    Acevedo ML, Alonso-Palomares L, Bustamante A et al Infectivity and immune escape of the new SARS-CoV-2 variant of interest Lambda. MedRxiv. 2021. July 1. Not indexed in PubMed
    Reuters Staff Lambda Variant Shows Vaccine Resistance Medscape August 2, 2021
    Kimura I, Kosugi Y, Wu J et al SARS-CoV-2 Lambda variant exhibits higher infectivity and immune resistance. bioRxiv. July 28, 2021 Not indexed in PubMed
  42. 42.0 42.1 Hamza S Beta Variant May Be Deadlier, South African Hospital Data Suggests. Increases in hospitalizations, deaths in country's second COVID-19 wave MedPage Today July 12, 2021
    Reuters Staff Beta Variant May Increase Hospitalizations and Deaths Medscape. July 16, 2021
    Jassat W et al Difference in mortality among individuals admitted to hospital with COVID-19 during the first and second waves in South Africa: a cohort study. Lancet Glob Health 2021. July 9 PMID: Free article
    Bekker LG, Ntusi NAB Lessons from two SARS-CoV-2 waves in South Africa. Lancet Glob Health 2021. July 9 PMID: Free article
  43. 43.0 43.1 Ellis R Delta Variant Infects 6 Vaccinated Guests at Outdoor Wedding. Medscape - Jul 13, 2021.
  44. 44.0 44.1 44.2 Planas D, Veyer D, Baidaliuk A et al. Reduced sensitivity of SARS-CoV-2 variant Delta to antibody neutralization. Nature 2021. July 8 PMID:
  45. 45.0 45.1 45.2 Kalter L Delta Variant Among the Most Infectious Viruses, CDC Says. Medscape - Jul 22, 2021.
    Goodman B Vaccine Breakthrough Cases Rising With Delta: Here's What That Means. Medscape - Jul 23, 2021.
  46. 46.0 46.1 Lopez Bernal J, Andrews N, Gower C et al Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant. N Engl J Med 2021. July 21 PMID:
    Fowlkes A, Gaglani M, Groover K, et al. Effectiveness of COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Frontline Workers Before and During B.1.617.2 (Delta) Variant Predominance - Eight U.S. Locations, December 2020-August 2021. MMWR Morb Mortal Wkly Rep. 2021 Aug 27;70(34):1167-1169 PMID: Free article.
  47. 47.0 47.1 Vignier N, Berot V, Bonnave N et al Breakthrough Infections of SARS-CoV-2 Gamma Variant in Fully Vaccinated Gold Miners, French Guiana, 2021. Centers for Disease Control & Prevention (CDC) Emerging Infectious Diseases 2021. 27(10) Oct
  48. 48.0 48.1 American Medical Association (AMA) AMA Morning Rounds. July 30, 2021
  49. 49.0 49.1 49.2 Walker M Pfizer and Moderna Go Head to Head Against Delta Variant knocked down effectiveness of one vaccine more than another, preprint finds. MedPage Today August 10, 2021
    Puranik A, Lenehan PJ, Silver E et al Comparison of two highly-effective mRNA vaccines for COVID-19 during periods of Alpha and Delta variant prevalence. medRxiv August 9, 2021
  50. 50.0 50.1 Reuters Staff Seven Die After Outbreak of Colombian Variant of COVID-19 at Belgian Nursing Home. Medscape. August 9, 2021
  51. 51.0 51.1 Griffin S Covid-19: Fully vaccinated people can carry as much delta virus as unvaccinated people, data indicate. BMJ 2021;374:n2074 August 19 PMID:
  52. 52.0 52.1 52.2 52.3 Mallapaty S Delta's rise is fuelled by rampant spread from people who feel fine. Nature News. 2021. August 19.
    Subbaraman N How do vaccinated people spread Delta? What the science says. Nature News. 2021. August 12.
  53. 53.0 53.1 Crist C COVID-19 Vaccines Still Highly Effective Against Hospitalization, CDC Data Show. Medscape. August 31, 2021
  54. 54.0 54.1 54.2 54.3 Lovelace B Jr WHO says it is monitoring a new Covid variant called 'mu' CNBC. September 1, 2012
  55. 55.0 55.1 55.2 Winning A South Africa Detects New Coronavirus Variant, Still Studying Its Mutations. Medscape. August 31, 2021
  56. 56.0 56.1 Mendez R WHO says Covid will mutate like the flu and is likely here to stay. CNBC Health and Science. September 7, 2021.
  57. 57.0 57.1 57.2 McNamara D How Concerned Should We Be About the Mu Variant? Medscape. Sept 9, 2021
  58. 58.0 58.1 Stephens S The Latest on the Delta Variant. MedPage Today. September 2, 2021
  59. 59.0 59.1 Adamoski D, Carvalho de Oliveira J, Bonatto AC, Wassem R, Nogueira MB, Raboni SM, et al. Large-scale screening of asymptomatic persons for SARS-CoV-2 variants of concern and Gamma takeover, Brazil. Emerg Infect Dis. 2021 Dec [date cited].
  60. Fontanet A, Autran B, Lina B, Kieny MP, Karim SSA, Sridhar D. SARS-CoV-2 variants and ending the COVID-19 pandemic. Lancet. 2021 Mar 13;397(10278):952-954 PMID: PMCID: PMC7906631 Free PMC article
  61. 61.0 61.1 61.2 Ellis R New COVID Strain Has Reached the US. Medscape. September 23, 2021
  62. 62.0 62.1 62.2 Reuters Staff UK Study Finds Vaccinated People Easily Transmit Delta Variant in Households. Medscape. October 29, 2021
    Singanayagam A, Hakki S, Dunning J et al Community transmission and viral load kinetics of the SARS-CoV-2 delta (B.1.617.2) variant in vaccinated and unvaccinated individuals in the UK: a prospective, longitudinal, cohort study. Lancet Infectious Diseases, 2021 Oct 29;S1473-3099(21)00648-4 PMID: PMCID: PMC8554486 Free PMC article
  63. 63.0 63.1 63.2 63.3 Steenhuysen J Delta Dominates the World, but Scientists Watch for Worrisome Offspring. Medscape. November 16, 2021
  64. 64.0 64.1 64.2 Miao H WHO calls special meeting to discuss new Covid variant found in South Africa with 'a large number of mutations' CNBC News. November 25, 2021
    Covid Live Updates: South Africa Identifies New Variant New York Times. November 25, 2021
    Callaway E Heavily mutated coronavirus variant puts scientists on alert. Researchers are racing to determine whether a fast-spreading variant in South Africa poses a threat to COVID vaccines' effectiveness. Nature News. November 25, 2021
    Stein P, Booth W Announcement of new virus variant alarms world, crashing stocks and banning flights. Washington Post. November 26, 2021
    Walker M New COVID Variant Sparks U.S. Travel Ban for Southern Africa. Characterized as "red flag," but questions remain about immune escape, transmissibility. MedPage Today November 26, 2021
    CBS News. November 30, 2021 Omicron COVID variant was in Europe before South African scientists detected and flagged it to the world.
    Walker M First Omicron Case Detected in the U.S. But Fauci cautions this is an "n of 1" case. MedPage Today December 1, 2021
    Walker M Omicron in 17 States; EUA for Monoclonals in Babies; President Biden Has a Cold. A daily roundup of news on COVID-19 and the rest of medicine MedPage Today December 6, 2021
  65. 65.0 65.1 Walker J Covid-19 Antibody Drugs Are Challenged by Omicron, Preliminary Testing Indicates. Regeneron said its antibody drug cocktail was found to lose effectiveness against the new variant. Wall Street Journal. November 30, 2021
  66. 66.0 66.1 Kimball S Pfizer CEO confident Covid treatment pill will be effective against omicron variant. CNBC. November 29, 2021
  67. 67.0 67.1 67.2 Crist C Omicron May Require Fourth Vaccine Dose, Pfizer Says. Medscape. December 9, 2021
    Kalter L Fauci: Boosters Work Against Omicron Medscape. December 15, 2021
  68. 68.0 68.1 Walker M WHO: Omicron More Transmissible, Not Necessarily Milder. When it comes to disease severity, "hope is not a strategy" WHO officials say MedPage Today December 8, 2021
  69. 69.0 69.1 Kuehn BM Delta Variant Wasn't Linked With More Severe Disease. JAMA. 2021;326(22):2251. Dec 14 PMID:
  70. 70.0 70.1 70.2 Crist C Omicron Variant Escapes Moderna Vaccine, but Booster Shot Helps. Medscape. December 16, 2021
    Goodman B Moderna Booster Increases Protection Against Omicron, Company Says. Medscape. December 20, 2021
    Doria-Rose NA, Shen X, Schmidt SD et al Booster of mRNA-1273 Vaccine Reduces SARS-CoV-2 Omicron Escape from Neutralizing Antibodies. medRxiv. December 15, 2021 PMID: PMCID: PMC8687471 Free PMC article
  71. 71.0 71.1 Firth S More Evidence Omicron May Be Weaker Than Prior Variants. Data "encouraging" but still "preliminary," says Fauci. MedPage Today December 29, 2021
  72. 72.0 72.1 Keeton R, Tincho MB, Ngomti A SARS-CoV-2 spike T cell responses induced upon vaccination or infection remain robust against Omicron. medRxiv. 2021. December 28.
  73. 73.0 73.1 Crist C Omicron Variant Appears to Cause Less Damage to Lungs, Studies Say. Medscape. January 3, 2022
    Diamond M, Halfmann P, Maemura T et al The SARS-CoV-2 B.1.1.529 Omicron virus causes attenuated infection and disease in mice and hamsters. Research Square. In Review. Nature Portfolio. December 29, 2021
  74. 74.0 74.1 Russell P Hospitalisation Risk from Omicron Variant 'Around a Third of Delta'. Medscape UK. January 4, 2022
  75. 75.0 75.1 Reuters Staff Omicron Estimated to Be 95% of Coronavirus Variants in US: CDC. Medscape. Jan 5, 2022
  76. 76.0 76.1 Reuters Health Information Omicron May Be Less Severe, but Not 'Mild': WHO Chief. Medscape. January 07, 2022
  77. 77.0 77.1 Garcia-Beltran WF, St. Denis KJ, Hoelzemer A et al. mRNA-based COVID-19 vaccine boosters induce neutralizing immunity against SARS-CoV-2 Omicron variant. Cell 2021 Dec 23; [e-pub]. PMID: PMCID: PMC8733787 Free PMC article
  78. 78.0 78.1 McNamara D Watch, but Don't Worry Yet, About New Omicron Subvariant. Medscape. Jan 25, 2022
  79. 79.0 79.1 Ellis R Omicron Survives Longer on Plastic, Skin Than Other COVID Variants. Medscape. Jan 25, 2022
    Hirose R, Itoh Y, Ikegaya H et al Differences in environmental stability among SARS-CoV-2 variants of concern: Omicron has higher stability. bioRxiv. Jan 19, 2022
  80. 80.0 80.1 Crist C Omicron Subvariant 1.5 Times More Contagious Than Omicron. Medscape. Jan 31, 2022
  81. 81.0 81.1 Danza P, Koo TH, Haddix M et al SARS-CoV-2 Infection and Hospitalization Among Adults Aged >= 18 Years, by Vaccination Status, Before and During SARS-CoV-2 B.1.1.529 (Omicron) Variant Predominance - Los Angeles County, California, November 7, 2021-January 8, 2022. MMWR Morb Mortal Wkly Rep. ePub: 1 February 2022 PMID:
  82. 82.0 82.1 82.2 Walker M 'Natural Immunity' Holds Up Against Severe Omicron Cases in Qatar Study. "Robust" protection from previous infection against hospitalization, death by reinfection. MedPage Today February 9, 2022
    Altarawneh HN, Chemaitelly H, Hasan MR et al Protection against the Omicron Variant from Previous SARS-CoV-2 Infection. N Engl J Med 2022. Feb 9 PMID:
  83. Ellis R Omicron Death Rate Higher Than During Delta Surge. Medscape. February 10, 2022
  84. 84.0 84.1 Ellis R Subvariant May Be More Dangerous Than Omicron: Study. Medscape. February 18, 2022.
    Yamasoba D, Kimura I, Nasser H et al Virological characteristics of SARS-CoV-2 BA.2 variant. bioRxiv preprint, February 15, 2022
  85. 85.0 85.1 Fiore K No Real-World Evidence BA.2 Is More Severe. WHO eases BA.2 concerns; South African data show no increase in severity. MedPage Today February 23, 2022
  86. 86.0 86.1 86.2 86.3 Steele RW, Bronze S Coronavirus 2019 (COVID-19) Variants Medscape. Feb 16, 2022
  87. 87.0 87.1 Reuters Omicron BA.2 Makes Up 23.1% of COVID Variants in US: CDC Medscape. March 16, 2022
  88. 88.0 88.1 Reuters Omicron Infections Are Contagious for at Least 6 Days. Medscape. March 18, 2022
    Boucau J, Marino C, Regan J et al Duration of viable virus shedding in SARS-CoV-2 omicron variant infection. medRxiv. March 2, 2022
  89. 89.0 89.1 Steele RW, Bronze S COVID-19 Variants Medscape. March 23, 2022
  90. Variant_Proportions_Weekly by strain surveillance
  91. California Department of Public Health Tracking Variants
    COVID Watch Viral Respiratory Surveillance for LA County
    LA County Daily COVID-19 Data
  92. 92.0 92.1 Kalter L New COVID Combo-Variant XE Found in UK. Medscape. April 5, 2022
  93. Phan T, Boes S, McCullough M et al First detection of SARS-CoV-2 Omicron BA.4 variant in Western Pennsylvania, United States. Journal of Medical Virology. 2022, May 9. PMID:
  94. 94.0 94.1 Maxmen A Why call it BA.2.12.1? A guide to the tangled Omicron family. Nature. News Explainer. May 27, 2022
  95. 95.0 95.1 95.2 Fiore K I Just Recovered From BA.2. Can I Get BA.4/5? As new variants gain foothold, here's what to expect. MedPage Today June 16, 2022
  96. 96.0 96.1 Crist C Omicron Carries Half the Risk of Long COVID as Delta: Study. Medscape. June 17, 2022
    Antonelli M et al Risk of long COVID associated with delta versus omicron variants of SARS-CoV-2. Lancet. 2022. June 18. PMID:
  97. 97.0 97.1 Hachmann NP, Miller J, Collier AY et al Neutralization Escape by SARS-CoV-2 Omicron Subvariants BA.2.12.1, BA.4, and BA.5. N Engl J Med. 2022. Jun 22. PMID:
  98. 98.0 98.1 Calder R New COVID subvariant could make you sweat at night. New York Times. July 9, 2022
  99. 99.0 99.1 Altarawneh HN et al. Effects of previous infection and vaccination on symptomatic omicron infections. N Engl J Med 2022 Jun 15; [e-pub]. PMID: PMCID: PMC9258753 Free PMC article
  100. 100.0 100.1 Putka S What to Know About the New BA.2.75 Omicron Subvariant. Now spreading in at least 10 countries, but it's too soon to tell how virulent or deadly it is. MedPage Today July 8, 2022
  101. 101.0 101.1 Syed AM, Ciling A, Taha TY et al Omicron mutations enhance infectivity and reduce antibody neutralization of SARS-CoV-2 virus-like particles. Proc Natl Acad Sci U.S.A. 2022. July 19
  102. 102.0 102.1 AMA Morning Rounds American Medical Association. July 22, 2022
    Hassan A The risk from the coronavirus is rising in much of the United States. New York Times. July 21, 2022
  103. 103.0 103.1 Prillaman M Prior Omicron infection protects against BA.4 and BA.5 variants. Nature News. July 21, 2022
  104. 104.0 104.1 104.2 Bowen JE, Addetia A, Dang HV et al Omicron spike function and neutralizing activity elicited by a comprehensive panel of vaccines. Science 2022. July 19. PMID:
  105. Madhusoodanan J Animal Reservoirs - Where the Next SARS-CoV-2 Variant Could Arise. JAMA. Published online August 3, 2022 PMID:
  106. 106.0 106.1 COVID Data Tracker
  107. 107.0 107.1 107.2 107.3 107.4 AMA Morning Rounds. Oct 3, 2022 American Medical Association
    Prater E BQ.1.1 is among the most immune-evasive COVID variants yet. It's coming in hot in the U.S. MSN. Oct 15, 2022
    O'Mary L New COVID Variant Gaining Traction in US. Medscape. Oct 17, 2022
  108. 108.0 108.1 108.2 McNamara D New COVID Subvariants Rising: How Concerned Should We Be? Medscape. October 18, 2022
  109. 109.0 109.1 D'Ambrosio A BN.1 Variant Rising; CA Sees First RSV Child Death; Sperm Counts Down Worldwide. Health news and commentary from around the Web gathered by MedPage Today staff. MedPage Today November 15, 2022
  110. CoVariants Home
    CoVariants Shared mutations
  111. Centers for Disease Control & Prevention (CDC) SARS-CoV-2 Variants
    SARS-CoV-2 Variant Classifications and Definitions
    Variant Proportions in the U.S Variant Map: US COVID-19 Cases Caused by Variants
    US COVID-19 Cases Caused by Variants
  112. 112.0 112.1 Wang Q, Iketani S, Li Z et al Alarming antibody evasion properties of rising SARS-CoV-2 BQ and XBB subvariants. Cell 2022. Dec 14;S0092-8674(22)01531-8. PMID: PMCID: PMC9747694 Free PMC article
  113. 113.0 113.1 Reuters staff Omicron Subvariant XBB Jumps to 18% of US COVID Cases: CDC. Medscape. 2022. Dec 27
  114. 114.0 114.1 Fiore K Here's What to Know About XBB.1.5. Its immune evasiveness didn't come at a cost in transmissibility, virologist says. MedPage Today January 4, 2023
  115. 115.0 115.1 115.2 115.3 Putka S XBB.1.5 Is Extra Infectious; Oldest Person in U.S. Dies; Vaccines for Honeybees? Health news and commentary from around the Web gathered by MedPage Today staff. MedPage Today January 9, 2023
    Ellis R New Omicron Subvariant Is 'Crazy Infectious,' COVID Expert Warns. Medscape. Jan 10, 2022
  116. 116.0 116.1 Henderson J Is Orthrus the Next Top-Dog COVID Variant? CH.1.1 now accounts for about a quarter of cases in the U.K. MedPage Today February 7, 2023
    Qu P, Faraone Evans JP et al Extraordinary Evasion of Neutralizing Antibody Response by Omicron XBB.1.5, CH.1.1 and CA.3.1 Variants. BioRxiv. January 17, 2023.
  117. 117.0 117.1 O'Mary L New COVID Variant on WHO's Radar Causing Itchy Eyes in Kids. Medscsape. April 12, 2023
  118. 118.0 118.1 118.2 118.3 118.4 O'Mary L US Has New Dominant COVID Variant Called EG.5. Medscape. August 7, 2023
    Schnirring L WHO adds Omicron EG.5 to variant monitoring as global COVID markers decline further. University of Minnesta, CIDRAP, July 20, 2023
    Wikipedia: Eris (dwarf planet)
    Abbasi J What to Know About EG.5, the Latest SARS-CoV-2 "Variant of Interest". JAMA. Published online August 18, 2023. PMID:
  119. 119.0 119.1 AMA Morning Rouns. August 21, 2023 American Medical Association
  120. 120.0 120.1 120.2 AMA Morning Rounds. August 24, 2023 American Medical Association
  121. 121.0 121.1 121.2 Harris E CDC Assesses Risk From BA.2.86, Highly Mutated COVID-19 Variant. JAMA. Published online August 30, 2023
  122. 122.0 122.1 AMA Morning Rounds. Dec 17, 2023 American Medical Association
    Berg S What doctors wish patients knew about COVID-19 oral antivirals. American Medical Association. Nov 23, 2023
  123. 123.0 123.1 AMA Morning Rounds. Dec 20, 2023 American Medical Association
    Roy S WHO says JN.1 COVID strain a 'variant of interest', poses low risk. Reuters. Dec 19, 2023
  124. 124.0 124.1 Lin II RG Early signs of rising COVID in California as new FLiRT subvariants dominate. Los Angeles Times. May 25, 2024
  125. Centers for Disease Control & Prevention COVID Data Tracker.