On the face of it the announcement by President Putin that Russia has registered the first vaccine against COVID-19 should be widely celebrated.
Let me pop your balloon. We know very little about the vaccine.
It's listed by the World Health Organization with the codename "Gam-COVID-vac", made by the Gamaleya Research Institute in Moscow.
It's based on a modified form of the adenovirus, which causes the common cold.
Image: Russian President Vladimir Putin says his daughter was vaccinated with 'Sputnik V'
And it's just completed a phase 1 study in 38 people - that's a trial to assess whether it has any major side effects and whether it produces a good immune response.
No data has been published - in contrast with other experimental vaccines in the UK, US and China.
But President Putin assured government ministers in a televised video conference that one of his daughters had been given two doses of the vaccine.
Although she initially had a slight fever she is now well and has a high antibody count, he said.
So far, so good.
But that's a long way from proving the vaccine protects people against infection.
That needs a phase 3 study involving several thousand people over many months, with some given the COVID-19 vaccine and others a jab against another disease.
The coronavirus infection rate can then be compared in the two groups to confirm whether the experimental vaccine is protective.
But the Russian vaccine won't start a phase 3 trial until later this week, so we just don't know whether it works.
It may be a quirk of the Russian regulatory system that allows a vaccine to be registered at a much earlier stage.
In Europe and the US authorities would want all the data before signing it off for wider use.
Image: Russia has registered more than 897,000 coronavirus cases
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Significantly, the vaccine is going to be distributed abroad under the name "Sputnik V", a reference, of course, to the first satellite to orbit the planet during the space race all those decades ago.
It's a dig at the West, more about geopolitics and national pride - another Russian "first" - than good science.
Does it matter?
Well, yes it does.
We know that a significant number of people are concerned about the safety of COVID-19 vaccines because they're being developed at such high speed.
If there are problems further down the line with the Russian prototype there is a risk it will undermine trust in vaccines that have been properly tested.
People may refuse genuine protection against the coronavirus.
And that could cost lives.