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New variants may shape the pandemic 

All viruses change over time, including SARS-CoV-2.

Rapid identification of new variants has been made possible with state of the art sequencing technology all over the world.

Tracking the course of the pandemic1

VOC: variant of concern; *Includes BA.1, BA.2, BA.3, BA.4, BA.5 and descendent lineages. It also includes BA.1/BA.2 circulating recombinant forms such as XE. WHO emphasizes that these descendant lineages should be monitored as distinct lineages by public health authorities and comparative assessments of their virus characteristics should be undertaken.1

SARS-CoV-2 variants of concern have caused spikes in infection rates around the world3

Alpha B.1.1.7

Beta B.1.351

Delta B.1.617.2

Omicron B.1.1.529

NTD: N-terminal domain; RBD: receptor-binding domain.
The Omicron variant has more mutations and spreads faster than Delta3-5
 BA.1 vs BA.2:
  • 21 identical mutations
  • 7 mutations and 1 deletion unique to BA.2
  • 9 mutations, 3 deletions, and 1 insertion unique to BA.1

BA.1.1 – differs from BA.1 by an additional R346K mutation

FP, fusion peptide; HR1, heptad repeat 1; NTD, N-terminal domain; RBD, receptor-binding domain; SD1, subdomain 1; 
SD2, subdomain 2.
Omicron variant spread from December 2021–January 2022 and 
December 2021–March 20225
 December 2021–January 2022

Line colour indicates transmission continent of origin and circle size is proportional to number of sequences collected.

 December 2021–March 2022

Line colour indicates transmission continent of origin and circle size is proportional to number of sequences collected.
REINFECTION
  • 5.41-fold increased risk of reinfection with Omicron vs Delta6
  • Estimated hazard ratio for reinfection was higher for Omicron (November 2021) versus Wave 1 (July–September 2020): 1.75 (95% CI: 1.48–2.10)7 
TRANSMISSION
  • Omicron multiplies 70 times faster than the Delta variant in the human bronchus, which may explain why Omicron may transmit faster between humans than previous variants8
 CI: confidence interval.Explore more Pfizer vaccines

Learn more about mRNA COVID-19 vaccine options from BioNTech and Pfizer

 Explore LoadingReferencesReferences:World Health Organization. Tracking variants of concern. https://www.who.int/en/activities/tracking-SARS-CoV-2-variants/ (accessed February 2023). European Centre for Disease Prevention and Control. Epidemiological update: SARS-CoV-2 Omicron sub-lineages BA.4 and BA.5. https://www.ecdc.europa.eu/en/news-events/epidemiological-update-sars-cov-2-omicron-sub-lineages-ba4-and-ba5 (accessed February 2023). Yahalom-Ronen Y, et al. Vaccines (Basel) 2022;10:291. Iketani S, et al. Nature 2022;604:553–556. GISAID. SARS-CoV-2 variants. https://www.gisaid.org/hcov19-variants/ (accessed February 2023). Ferguson N, et al. https://www.imperial.ac.uk/mrc-global-infectious-disease-analysis/covid-19/report-49-omicron/ (accessed February 2023). Pulliam JRC, et al. Science 2022;376:eabn4947. doi: 10.1126/science.abn4947. [Epub ahead of print]. HKUMed News release. https://www.med.hku.hk/en/news/press/20211215-omicron-sars-cov-2-infection?utm_medium=social&utm_source=twitter&utm_campaign=press_release (accessed February 2023).About Treatment options for COVID-19

Find out about the therapeutic targets in the viral lifecycle

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Learn about different types of vaccines and how they may prevent disease

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Adverse events should be reported. Reporting forms and information can be found at https://www.pfizersafetyreporting.com/#/en

 

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