With the Omicron variant just adding to uncertainty in the run-up to Christmas, Spain's health ministry is warning of increasing evidence that the Omicron variant "escapes the immune response caused by previous variants and by vaccines".
The latest report from the Centre for the Coordination of Health Alerts and Emergencies (CCAES) points to Omicron being "the most genetically divergent" of variants detected during the pandemic, which "raises a great concern that it may be associated with a significant reduction in the effectiveness of the vaccine and an increased risk of reinfection".
"Several" of the changes in the sequence that encodes the spicule protein (virus entry gate) of the Omicron variant "are associated with the immune escape of the neutralising antibodies or other properties".
The CCAES stresses that "more studies are needed on neutralisation 'in vitro', the effectiveness of the different vaccines, as well as additional data on the risk of reinfection in people with previous immunity and the severity of reinfection in exposed populations to different variants of SARS-CoV-2 during previous pandemic waves".
Regarding the seriousness of cases, the CCAES points out that, of all cases of Omicron reported in Europe so far, "half have been asymptomatic and the other half mild symptoms." No cases of serious illness, hospitalisations or death have been reported.
Nevertheless, the health ministry is calling for caution because few cases have so far been detected and these are very recent. "Results of severity often take several weeks to be seen and more time to become apparent at the population level, which would affect hospital occupancy rates". Most of the cases detected in the EU, for which there are data so far, have been young or middle-aged people who were fully vaccinated.