European Union plans to buy 4 mRNA shots for every human in the EU in 2022. Why?

According to the Business Standard:

Later on Wednesday the President of the European Commission said the EU was in talks with Pfizer and BionTech for a new contract for 1.8 billion doses, confirming a Reuters report from last week. “We need to focus on technologies that have proven their worth. mRNA vaccines are a clear case in point,” she added.

There are 448 million humans in the EU.  Why in heaven's name would each one of them, regardless of age, need 4 shots in 2022 after they are fully vaccinated this year?  

Here in the US, as we approach herd immunity, it looks like approximately half the population does not want these experimental shots, at least not at this time.  If the same holds true in Europe, are they planning for 8 shots per person?  Or forced vaccinations?