What we know
The Omicron variant has 30 changes to it including a small insertion in the spike protein and three small deletions. Around 50% of these changes are in the receptor binding domain - this is the part of the spike protein use to bind to human ACE-2, which is the enzyme the coronavirus targets to enter cells and infect a person. If there are mutations here this makes the spike protein less recognisable to the antibodies made in response to either a vaccination or natural antibodies.
The bottom line is that the Omicron is different.
It is a worry
The concern is that these changes above mean that the virus transmits more quickly. Early PCR tests showed that 90% of 1,100 new cases reported November 24 in a SA province were caused by the new variant. SA President Cyril Ramaphosa said that the average daily cases rose from 500 case in the previous week to 1,600.
It is also uncertain how bad it is
Being more transmissible is not necessarily a bad thing if the virus has milder effects. It could actually be a good thing as Eamonn pointed out that catching a less severe variant results in lesser illness and then confers 'immunity'.Anecdotal comments suggest that the variant is not an obvious concern.
Novavax, Moderna, & Johnson & Johnson are all onto to testing the new variant against its vaccines. Even the variant is able to evade the currentvaccine Moderna's Chief Medical Office said a new vaccine variant could be ready early next year.
The one thing that strikes me is that this variant news broke over the US thanksgiving holiday, a natural down time for economic data and news activity. There are so many unknowns here there is a strong case for both caution and dip buying. At any rate, note that vaccine companies like Moderna are confident in being able to put in a fresh response even if the variant does evade existing vaccines. However, note that the Moderna CEO now thinks that the current vaccine will be much less effective against the variant, so that is a near term downside in risk.