Boris Johnson interview on coronavirus vaccination figures

The transcript discusses the largest vaccine rollout in the country's history, highlighting achievements in vaccine distribution compared to Europe. It outlines efforts to ramp up operations with the help of the army and volunteers, and addresses challenges in testing and distributing vaccines. The speaker projects that tens of millions of vaccines will be distributed by the end of March.

What challenges are mentioned regarding getting vaccines properly tested and distributed?

What is the expected number of vaccines to be administered by the end of March?