Your questions, answered
“The new covid-19 variant is said to be ‘more contagious’ than the old one. What does that mean? Are masks not effective?” — Doug in California
First things first: Masks are still effective. In fact, they are probably even more important now because we know that there's a variant in the mix that is spreading faster.
There seems to be a scientific consensus that the new variant is somewhere between 50 and 70 percent more transmissive, according to Stat News. British Prime Minister Boris Johnson also referenced that range Monday night in his announcement that England is going into its third national lockdown.
There doesn't appear to be anything else that's markedly different about this variant, particularly in how it affects an infection; it does not trigger a more severe case of covid-19 and it is not more deadly. So what makes it more contagious?
Researchers have narrowed it down to a couple of possible factors.
It appears that infections caused by this variant produce more viral load in the upper respiratory tract, which means there's more virus available to spread when an infected person coughs, sneezes, talks or even just breathes. It's difficult to say for sure if this is a reason, because it depends highly on when the patient is tested (if patients aren't tested in peak illness, their peak viral load might not be captured).
The variant also has a mutation that scientists say could help the virus attach to cells. This mutation affects the spike part of the virus, which is where it comes in contact with a cell and latches on. If that spike is more efficient at or capable of attaching to a cell, then it's more likely to result in an infection. Another variant in South Africa also had this mutation and was similarly more transmissible.
Perhaps this variant has evolved to counteract the body's immune response, to a certain extent, which would make infection more likely when it's encountered. It could also just replicate faster than its predecessors, which would also explain why researchers are seeing a higher viral load.
More likely than not it's some combination of the above. Researchers are still trying to determine exactly what makes this variant spread faster, and what conditions allowed it to occur.