https://www.independent.co.uk/news/uk/astrazeneca-oxford-europe-fears-b1982611.html
It is "speculated" that the UK's death rate is low compared to Europe due to many of the first people here being jabbed by AstraZeneca.
Older vaccine technology may have unknown advantages over mRNA. Novavax has just been approved, and it is an even older technology than the Viral vector from AZ.
It will take about a month to see the impact of Omicron on the death rate in the UK, and if it matches South Africa's lower death rate. (Older population in the UK, but a more vaccinated one).
I originally had 2 doses of AstraZeneca, and more recently a booster of Pfizer. Maybe another booster from Novavax would make it all 3 vaccine technologies to create a lekker poikie kos.