Pfizer and its partner BioNTech will apply today for emergency authorisation in the US for their COVID-19 vaccine.
It will be the job of the US Food and Drug Administration (FDA) to decide if the vaccine is safe to implement.
It is not clear how long the FDA will take to study the data.
However, the US government expects to approve the vaccine in the first half of December.
Data from an advanced trial showed the vaccine protects 94 per cent of adults over 65.
The trial involved 41,000 people worldwide.
Half were given the vaccine, and half a placebo.
The UK has pre-ordered 40 million doses and should get 10 million by the end of the year.