The SARS-CoV-2 Omicron variant of concern (VOC) is rapidly replacing SARS-CoV-2 Delta in most European Union/European Economic Area (EU/EEA) countries, and is broadly following a west-to-east progression.
The risk to public health posed by the spread of the Omicron VOC in the context of ongoing Delta VOC transmission in the EU/EEA is assessed in this update.
ECDC encourages the use of this protocol as a basis for studies aiming at assessing vaccine effectiveness in semi-closed settings following the identification of a COVID-19 outbreak, as its use in the EU/EEA can facilitate results comparability from different outbreak investigations.
The number of countries reporting SARS-CoV-2 Omicron variant of concern (VOC) cases continues to increase globally, with a total of 352 confirmed cases reported by 27 countries as of 16.00 on 1 December 2021, including 70 confirmed cases reported by 13 European Union and European Economic Area (EU/EEA) countries.
This technical report provides a set of interim public health considerations to support EU/EEA public health authorities taking decisions on the administration of COVID-19 vaccines to children aged 5 11 years.
A SARS-CoV-2 variant belonging to Pango lineage B.1.1.529, with a high number of S-gene mutations compared to the original virus was detected at the beginning of November 2021. On 26 November 2021 the variant was designated a variant of concern (VOC) and assigned the label Omicron by the World Health Organization (WHO).