Lab experiments conducted by the company complement others emerging from South Africa and other labs around the world in showing that antibodies produced by people vaccinated with their jab are less potent against the new variants.
This is to be expected given they have a number of mutations that appear to help these viruses escape our immune response.
While we'd all hoped the first generation of vaccines would be perfectly effective against Covid-19, we can't stop the virus evolving and it was always assumed we might need to change our game.
The good news for us in the UK right now is that Moderna's experiments suggest their vaccine will work perfectly well against the more infectious B.1.1.7 variant that's causing the UKs' current coronavirus surge.
But it's also encouraging that big vaccine companies - and I understand Moderna isn't alone in designing new versions of its Covid-19 vaccine, it's just the first to announce it - are working now to try and get ahead of the virus.
New vaccines, especially those, like Moderna's and Pfizer's, that are based on just a stretch of the virus's RNA molecule, are simple to produce new versions of.
And because the vaccines have already been tested in big clinical trials it's possible to test the new versions in fairly simple, and short, "bridging studies."
I understand these studies can take just weeks to complete.
So, if we do end up discovering - and it definitely remains an "if" at this stage - that we will need updated vaccines, we should have them on the shelf, ready to deploy as early as this Autumn.