Some had faith in the new mRNA technology, while others preferred to rely on more time-tested methods. Sometimes articles hide a great deal in one seemingly innocuous sentence. From what I've learned from Europeans, there's only one vaccine candidate of that nature the EU considered, a Sanofi Pasteur/GlaxoSmithKline combo, the former providing the infamous spike protein, the latter an adjuvant. Everyone expected this…
Chinese and the Russian vaccines were not even considered. Now those are used in mass vaccinations, soon EU would be behind all countries but those who barely have any government at all. People don't even want to talk about that, as if those alternatives don't exists. Non-EU countries in Europe are getting them. Serbia(6.1) and Turkey(2.3) are already close to EU average(2.6) or better on the vaccination process.
This is based on the theory that the immune system response to Oxford's virus vector is mostly negating the benefit of the second dose taken 21 days after the first. Gam-COVID-Vac gets around this by using different viruses for each dose, and has 90% efficacy results from their Phase III trial. Unfortunately, no one can yet manufacture it in anything like bulk quantities, but they have set up manufacturing partnerships with a whole bunch of countries from India to South Korea.