How effective are vaccines against omicron?

Melissa Hawkins in The Conversation:

The preliminary data about omicron and vaccines is coming in quickly and is revealing lower vaccine effectiveness. Best estimates suggest vaccines are around 30%-40% effective at preventing infections and 70% effective at preventing severe disease.

preprint study – one not formally reviewed by other scientists yet – that was conducted in Germany found that antibodies in blood collected from people fully vaccinated with Moderna and Pfizer showed reduced efficacy in neutralizing the omicron variant. Other small preprint studies in South Africa and England showed a significant decrease in how well antibodies target the omicron variant. More breakthough infections are expected, with decreased immune system ability to recognize omicron compared with other variants.

More here.