Omicron (B.1.1.529) classified as a SARS-CoV-2 Variant of Concern

26 November 2021
News release

BRIEFING NOTE

Event: WHO has designated the variant B.1.1.529 a variant of concern, named Omicron, based on advice from WHO’s Technical Advisory Group on Virus Evolution (TAG-VE).  

Read the full announcement.

 

Key messages

  1. This variant is of concern because it has some mutations that may have an impact on how it behaves.
  2. Countries should enhance surveillance and sequencing, share genome sequences with public databases, and report initial cases/clusters to WHO, while also continuing to implement effective public health measures.  
  3. The more COVID-19 circulates, the more opportunities the virus has to change, the more mutations we will see. The most important thing people can do is reduce their risk of exposure to the virus.

 

Reference material:


Key points

Q: Why did WHO designate this variant a variant of concern?

WHO has designated the variant B.1.1.529 a variant of concern, named Omicron, on the basis of advice from WHO’s Technical Advisory Group on Virus Evolution.  Read the full announcement. This decision was based on the emerging evidence from South Africa that the variant has caused a detrimental change in COVID-19 epidemiology.

 

Q: What do we know about the variant?

  • This variant was reported at a remarkable speed. Earliest cases so far were detected on 9 November and reported to WHO on 24 November 2021.
  • This variant has a large number of mutations, some of which are concerning. Preliminary evidence suggests there may be an increased risk of reinfection with this variant, as compared to other VOCs.

    Q: Do tests still work on this variant?

    Most diagnostic tests continue to work and can detect this variant.

    Several labs have indicated that for one widely used PCR test, one of the three target genes is not detected (this is called S gene dropout or S gene target failure). This is similar to what we saw with the Alpha variant. So, we can use this PCR test to rapidly identify the likely presence of the new variant, and help us prioritize which samples need to be sent for genome sequencing, in order to confirm the new variant.

     

    Q: Do current vaccines still work on this variant?

    It is important to get vaccinated for protection against the widely circulating variants. Researchers are  looking into potential impact on vaccines and other tools.

     

    Q: What is WHO doing to learn more about this variant?

  • WHO is closely monitoring the Omicron variant, which was designated a Variant of Concern on the advice of  WHO’s TAG-VE on 26 November. Read the announcement, more on TAG-VE.  WHO’s TAG-VE will meet again soon to coordinate and align global research on this topic, and will continue to meet regularly.
  • Researchers are working to understand more about the mutations and what they potentially mean for how transmissible or virulent this variant is, and how they may impact diagnostics, therapeutics and vaccines. It will take a few weeks for us to understand what impact this variant has.
  • Now that this variant is a variant of concern, there are actions WHO recommends, as we have for other VOCs: countries should share genome sequences and report initial cases or clusters to WHO, they should perform field investigations and laboratory assessments to better understand its impact.

     

    Q: What can people do to protect themselves?

  • The most important thing people can do is reduce their risk of exposure to the virus. We know how to do so: get vaccinated, wear a mask, keep a distance, avoid poorly ventilated or crowded spaces, keep your hands clean and cough or sneeze into your elbow.
  • The more COVID-19 circulates, the more opportunities the virus has to change, the more mutations we will see. It is essential that we all continue to work to reduce the circulation of COVID-19. 

    Q: What should countries do?

    From the announcement:

  • Enhance surveillance and sequencing efforts to better understand circulating SARS-CoV-2 variants.
  • Submit complete genome sequences and associated metadata to a publicly available database, such as GISAID.
  • Report initial cases/clusters associated with VOC infection to WHO.
  • Where capacity exists and in coordination with the international community, perform field investigations and laboratory assessments to improve understanding of the potential impacts of the variant epidemiology, severity, effectiveness of public health and social measures, diagnostic methods, immune responses, antibody neutralization, or other relevant characteristics.