How worried should we be about new more infectious Covid-19 variants? Well, since they first started to emerge at the end of last year, it's been an open question.
But now the first data is starting to come in. I hate to say it, but the news is not great - but nor is it terrible. And it's still too early to tell how significant the impact on our vaccination efforts might be.
Professor Ravi Gupta at Cambridge University has now published some of the first findings on how effective vaccines might be against the "English variant" of Covid-19 called B1.1.7.
His study - which hasn't yet been peer-reviewed by other scientists - shows that antibodies from people vaccinated against Covid with the Pfizer/Biontech vaccines are between 3 and 6 times less effective at neutralising the new variant virus compared to previous strains.
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It's a significant finding because it shows that even in people who mount a good antibody response to the vaccine, its effectiveness against the new strain is reduced.
The reduction in response is "modest" according to Prof Gupta: "The response should still be adequate to protect someone from infection."
But it could indicate potential issues in individuals who mount a less robust antibody response to the vaccine. Evidence from his work, and others, suggests older people - who are of course more vulnerable to severe Covid - may be in this group.But it's impossible to tell from lab experiments like this just how much weaker vaccine effectiveness might be.
It's likely other parts of our immune system, like the T-cell response could mitigate against some deficiency in the antibody response.
Only real-world evidence from people currently being vaccinated against Covid and whether or not they get infected with the new variant will answer that question.
In a sperate, as-yet-unpublished study, Professor Penny Moore from South Africa's National Institute of Communicable Diseases, has done a similar study looking at how well antibodies from people previously infected with Covid respond to the new variant circulating there.
The B.1.351 variant that was first identified in South Africa, and the unrelated, but similar, P.1. variant circulating in Brazil are of more concern to virologists because they have an additional mutation to the UK variant that might make "escape" from the immune system primed against previous covid infection or by vaccines even more likely.
She found that in samples from 44 individuals who had recovered from Covid, antibodies from 21 of them didn't recognise the new variant - suggesting an almost 50% reduction in antibody response.
Significantly the samples which didn't respond were from individuals with a weaker response overall, many of whom were older.
So far, there is no data from South Africa or anywhere else on how well vaccines may work against the new variant.
But as we reported last week, that crucial evidence should be available soon.
The general feeling among the experts is that vaccines should still be effective against all variants of the virus, even if their potency is reduced somewhat.
However, the longer we take to roll out vaccines, and the more individuals there are out there infected at any one time, the more opportunity there is for this master shapeshifter of a virus to find new ways of escaping.