The European Medicines Agency (EMA - which was located in London before Brexit, but is now in Amsterdam) has a page on the authorization process:
https://www.ema.europa.eu/en/about-us/what-we-do/authorisation-medicines
In short, companies that want to sell new medicine that is not generic and requires a prescription in the EU need to get it assessed by the EMA. The Agency then provides a recommendation to the European Commission which decides on approvals. Once that's been granted, the product can be sold in all EU countries, plus Iceland, Liechtenstein, and Norway. So nothing to do with Brussels summits or political games (a ridiculous idea for medicine anyway). They have a nice little infograph explaining why a centralized process is beneficial:
I haven't read any arguments on the vaccine process, but I would think that approving the vaccining centrally makes sense. The EMA exists already, why not use it? Also, this creates fairness among member states; no advantage to countries with greater approval process capacity. Plus, no need to add burden to the current work of individual countries by having a few dozen individual approval processes. Finally, given all the conspiracy theories out there and existing vaccine hesitancy, it seems more secure to me to use the known procedure, rather than fuelling suspicion or increasing safety concerns by expiditing the approval process.
Interestingly, as it turns out, the British Medicines and Healthcare products Regulatory Agency (MHRA) seems to have followed the exact same process as the EMA. Which provides another reason against countries using individual processes: why go there is they're using the same method anyway?) This CNN article discusses exactly that:
https://www.cnn.com/2020/12/02/uk/uk-pfizer-vaccine-approval-gbr-intl/index.html
While they keep mentioning this rolling review of the MHRA and how it is only used to expedite approvals in emergency situations, they say that the EMA also used it and even started at the same time. So there is actually no difference there. The only unique explanation I see is someone's suggestion that Pfizer/BioNTech would have worked particularly closely with the MHRA, thus allowing it to move more quickly than others.
So, why did the UK go it alone? Maybe they knew they could make these Pfizer/BioNTech contacts work for them. Or maybe it's just in the spirit of Brexit. But in the end, it seems they really just did the same thing as the EU - except on their own.
