The U.K. reported 1,325 new coronavirus deaths on Thursday, marking its highest daily death toll yet.

Why it matters: The massive spike in deaths is in part fueled by a highly transmissible COVID-19 variant that's spreading rapidly throughout the United Kingdom and threatening to overwhelm hospital systems.

Between the lines: The figure is even worse on a per capita basis than the record 4,000 COVID-19 deaths reported in 24 hours in the U.S. On Friday, London Mayor Sadiq Khan declared a "major incident" because of the virus, which has infected 1 in 30 Londoners.

The big picture: The U.K, which is in full lockdown for at least the next six weeks, was the first country in the world to approve and begin administering both the Pfizer vaccine and Oxford-Astrazeneca vaccine.

• Earlier Friday, British regulators cleared the Moderna vaccine for emergency use.
• The Centers for Disease Control (CDC) notes that while the new coronavirus variant is more transmissible, there is "no evidence to suggest that the variant has any impact on the severity of disease or vaccine efficacy."