Omicron first detected in Botswana and South Africa at the end of November 2021, classified as a variant of concern by the WHO and CDC by December 1st, 2021 after rapid spread to multiple areas of the world, and evidence of community transmission
Preliminary data indicates increased transmissibility of Omicron compared to the currently dominant Delta
In-vitro data indicates a significant reduction in neutralization titers of vaccinee sera – however, sera from individuals recently boosted with an mRNA vaccine had a minimal reduction in neutralization capacity compared to Delta
Increasing rates of breakthrough infections in South Africa and the UK confirming suspicions of decreased vaccine effectiveness of primary vaccine series, early data shows that mRNA boosters increase levels of protection, though still lower than protection against other variants
Vaccination protection against severe disease appears to still be quite good, however severe disease/death are lagging indicators and a definitive conclusion cannot be made at this time
Most therapeutic monoclonal antibodies currently approved by FDA and in use do not neutralize Omicron, however therapies targeting the host immune response are anticipated to retain effectiveness
Badea, A; Reeder, B; Groot, G; Miller, L. What is the epidemiology of the Omicron variant and its impact on health care? 2021 Dec 22, Document no.: EOC211220 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 10 p. (CEST rapid review report).