The announcement that the coronavirus strain sweeping Britain could be more deadly as well as more transmissible has raised fresh concerns about the variant that has spread to dozens of countries.
Initially British experts said that their evidence suggested the new strain circulating in the UK — one of several to have emerged internationally in recent months — was between 50 percent and 70 percent more transmissible.
On Friday, however, the government said the new variant could also be 30-40 percent more deadly, although it stressed the assessment relied on sparse data.
What has changed?
In mid-January, two separate studies by London School of Hygiene and Tropical Medicine and Imperial College London were presented to Britain’s New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG).
They linked data from people who tested positive for the virus in the community — rather than in hospital — with death data and found a roughly 30 percent increase in the risk of death associated with the new strain.
The groups used slightly different methods, but both matched people with the new variant to those with the older variants, taking into account other variables like age and location and controlling for hospitals being under pressure.